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I

THE CIPT OF

UF

}. Ordnance Dap«Ttin«nt Dt»cuRwnt No. 2034

RAILWAY ARTILLERY

A REPORT ON
THE CHARACTERISTICS,
SCOPE OF UTILITY, ETC.

OF

RAILWAY ARTILLERY

IN TWO VOLUMES

VOLUME I

War Department,

Office of the Chief of Ordnance,

March 16, 1920.

This work on Railway Artillery is a Report on the Characteristics,

Scope of Utility, etc., of Railway ArtiUeiy, presented by H. W.

Miller, lieutenant colonel of Ordnance. It has likewise been prepared

for publication by Lieut. Col. Miller. This report is approved for

publication.

C. C. Williams,

Major General, United States Army, Chief of Ordnance.

(1)

382212

CONTENTS.

Preface. Paragraphs.

Historical introduction l-]6

Sec. I. ClaaBification of types of railway artillery 16-38

2. Scope of utility of railway artillery 39-80

3. Characteristics of existing types of railway artillery 81-403

4. Practical qualifications of railway artillery for land warfare and

coaat defense 404-488

5. Procedure in preparing for action in land warfare 489-573

6. Preparation 61 firing data and scheme of fire control in land warfare. 574-593

7. AsBembly, disposition, and maintenance of railway artillery in land

warfare 594-652

8. Equipment for railway artillery 653-658

9. Summary of recommendations 659-663

10. Railway clearances and tables of classified information 664-689

Appendix I. The German long-range gim and the bombardment of Paris. . 690-739

II. Study of the relative efficiency of different calihers 740-755

III. The German defenses on the coast of Belgium 756-85 9

(3)

PREFACE.

The following treatise on railway artillery was originally sub-
mitted as a part of the final report of the Railway Artillery Unit,
Artillery Section, Engineering Divisioni Office of the Chief Ordnance
Officer, American Expeditionary Forces in Prance. This report was
made up at the close of the World War of 1914-1918, and was a
revision of a sijnilar report prepared by the undersigned in April,

1918. The second report was finished and submitted in August,

1919, and covered, as fully as available information would permit,
all railway artillery completely or partially designed by ourselves,
our aUies, and our enemies in that war.

In preparing this revised report, two factors were kept particularly
in mind with reference to the change in railway artiQery requirements
of the United States Army, which had taken place since the completion
of the first report.

The first factor is the time available for the construction of the
artillery, throughout the period of active warfare. The aim was to
mount, in the shortest possible time, the greatest possible number of
available heavy guns on any type of mount that had been found
satisfactory for land warfare in France. Only limited machine
facilities were available and speed was the essence of every problem.
Now that the war is ended conditions are vastly different; we are
not in so great a hurry as we were a year ago, and we may assume
that any, or all, machine facilities that might be required for any type
of carriage are available.

The second factor is the characteristics required of the mount.
I>uriiig the active period of the war, as noted above, any mount
which had been found satisfactory for land warfare would serve;
now only such mounts as are adaptable also to coast defense should
be considered for new design and construction.

It is the object, therefore, of this revised report: First, to embody
in available form as much as possible of the information concerning
railway artillery acquired through experience in the war just ended;
and second, to indicate the application of this information and the
lessons learned to the present and futxu'e problexns of the Ordnance
Department, the formation of a new program of construction for
railway artilloy.

(5)

The recommendations contained herein should not be considered
official, since they have not been so approved by any regularly con-
stituted board of the Ordnance Department." They are the final
conclusions of the writer based upon over two years close association
with engineering work on railway artillery both in Europe and
America.

The material contained herein has been obtained from a large
number of sources which may be summarized as follows:

(a) Examination of French railway artillery in French artil-
lery parks, heavy artillery proving grounds, shops, and
on the front.
(6) Examination and study of designs of railway mounts of
all types, and conference with designing engineers of
the Ordnance companies in France and England who
have been responsible for the greater number of the
railway artUlery designs.

(c) Examination of captured German materiel and study of

• captured documents.

(d) Consultation and cooperation with Staff of American

Railway Artillery Reserve and Heavy Artillery School
in France.

(e) Study of all bulletins and regulations issued by the

French and English services for railway artillery.
(/) Observation of French and English Railway Artillery in

action and conference with Railway Artillery personnel

of French, English, and American Armies.
(g) Eighteen months cooperation with the French services

directing the design, manufacture, maintenance, and

field service of railway artillery.
Particular reference is made throughout the text to specific pub-
lications, etc., listed under the bibliography, from which data has
been secured, or in which additional information may be found.

Much of the material given in the descriptions of the mounts
belonging to our allies in the European war as well as the tabulated
data on weights, ballistics, etc., is. considered by these allies as being
'confidential and, at their request, is printed and issued to our service
as such. For this reason the report has been divided and is published
in two parts. The one part contains all information of a general
character, as well as the descriptions and tabular data on the American
and German mounts. The other volume contains descriptions and
tabular data on all of the French, British, and Italian mounts and is
issued as a confidential publication and is not for general distribution;
it is available only for official Army use. This, of course, includes
its use as a reference work in regularly constituted Army schools.

The description of the German long-range gun and of the bom-
bardment of Paris given under the heading of Appendix I is con-
sidered as going properly in this work, because the guns instrumental
in the bombardment were mounted on a railway carriage. The
^* Study of the relative eflBiciency of different calibers'' given under
the headmg of Appendix II is included because it has an important
bearing in the discussion given on the ''Scope of Utility of Railway
Artillery," and on the conclusions with reference to the types of
guns recommended for future construction. The description of the
coast defenses installed by the Germans in Belgium is given, under
the heading of Appendix III, because these defenses included railway
artillery and because the future problem of America with reference
to railway artillery is so intimately connected with the plans on
coast artillery.

The undersigned desires to acknowledge his indebtedness to Capt.
W. F. Dietrichsen, who has assisted in the collection of all data and
preparation of the original report, and to Maj. Hugh Pastoriza, who
has assisted so effectively in preparing this revision. Appendix II
on the ''Relative efficiency of the different calibers'' was prepared
by Maj. Hugh Pastoriza and Capt. R. H. Kent.

H. W. Miller,
Lieutenant-Cohnd, Ordnance Department, United States Army.

CHARACTERISTICS, SCOPE OF UTIUTY, ETC., OF

RAILWAY ARTILLERY.

HISTORICAL INTRODUCTION.

1. Railway Artillery seems not to have been recognized as an
important and separate subdivision of Artillery before the outbreak
of the World War, 1914-1918. For this reason the idea and the
material are thought of as new developments, whereas in fact both
appeared almost simultaneously with the widespread adoption of
railway transportation.

2. The earliest railway artillery of which the writer has been able
to find any record was employed in the Confederate Army under
Haj. Gren. J. Bankhead Magruder, on June 29 and 30, 1862, at Savage
Station, on the Richmond & York River Railway, about 10 miles
east of Richmond, in one of the ** Seven Days' Battles." A sketch
of this mount according to the best data available is given in plate 1.
Apparently the credit for the conception of the idea for the construc-
tion of such a battery should be given to Gen. Robert E. Lee. Fol-
lowing is a copy of the correspondence between Gen. Lee and the
authorities in Richmond responsible for the construction of the mount :

[A.— Official records of the War of the RebeUion, Volume XI, part 2, page 574 (1).1

Headquarters, June 5(k^ 1862.

Col. J. GOROAS,

Chief of Ordnance Dept .

Colonel: Is there a poedbility of constructing an iron-plated battery, mounting

a heavy gun on trucks, the whole covered with iron, to move along the York River

Railroad? Please see what can be done. See the Navy Department and officers.

If a proper one can be got up at once, it will be of immense advantage to us. Have

you got any mortan that we could put at some point on the railroad?

Very respectfully,

R. E. Lee, General.

[ B .-^ame reference, pages 575-570 ( 1 ) .]

Headquarters, Near Richmond^ Fa., June 5ffc, 186S.
Capt. GsoROB Minor,

Chief of Ordnance and Hydrography:
The Armstrong gun, if mounted on a field carriage with its supply of projectiles,
will be of immense importance to us. Can we not have it in the morning? The
smaller gun (IHiirott) I think we have enough at present. I am very anxious to have
a railroad battery. I wrote to Colonel Gorgas on the subject this morning and asked
him to get you and Brooke to aid him. Till something better could be accomplished

(9)

10

I propose a Dahlgren or columbiad, on a ship's carriage, on a railroad flat, and one of
your Navy iron aprons adjusted to it to protect gun and men. If I could get it in posi-
tion by daylight tomorrow, I could astonish our neighbors. The enemy cannot get
up his heavy guns except by railroad. We must block his progress.

Very respectfully and truly,

R. E. Lbe, Oeneral.
[C— Same reference, page 610 (1).]

Headquartebs, Duhh*s Houh^ Va., June 21 , 1862.
Hon. S. R. Mallort,

Secretary of the Navy^ Richmond^ Va.
Sir: I have been informed by Colonel Gorgas that the railroad battery^ will be
ready for service tomorrow. Inasmuch as this battery has been constructed by the
Navy, I would be pleased if you would assign an officer and a requisite number of
men to take charge of and operate it. If you desire to do so, I request that you will
designate the officer at once, as I wish to place the battery in position tomorrow. I
am very much obliged to you for your kindness as well as promptness in its con-
struction.

I am, very respectfully, your obedient servant,

.Xv. iif. IjEE.
[D.— Same reference, page 615 (1).]

Office of Ordnance & Hydrography,

Richmond, Va., June 24, 1862.
General R. E. Lee,

Comdg.y Ac, near Richmondy Va.

General: The railroad iron-plated battery designed by Lieut. John M. Brooke,

C. S. Navy, has been completed. The gun, a rifled and banded 32-pounder of 57 cwt.,

has been mounted and equipped by lieut. R. D. Minor, G. S. Navy, and with 200

rounds of ammunition, including l&-inch solid bolt shot, is now ready to be transfered

to the Army. I have the honor to be.

Very respectfully, your obedient servant.

George Minor,

Commander, in Charge.

Numerous records are available of the service of this mount in
the battle mentioned. Following are extracts from some of these
records and references to others:

[£.— Official records of the War of the Rebellion, volume XI, part 2, page 664.(1)]

extract from report of MAJ. OEN. J. BANKHEAD MACO RUDER, C. 8. A., OPERA-
TIONS JUNE 2»-30, 1862, AT 8AVAQE STATION.

Taking my position on the railroad bridge, which commanded a good view of the
fight and the enemy's line of battle, I directed the railroad, battery, commanded
most efficiently by Lieutenant Barry, to advance to the front, so as to clear in some
degree, the deep cut over which the bridge was thrown, and to open fire upon the
enemy's masses below, which was done with terrible effect. The enemy soon brought
the fire of his artillery and infantry to bear upon the raUroad battery and bridge
while he advanced a heavy line of infantry to support the troops already engaged to
capture our artillery and turn our right flank.

[ F.— Same re fercnce, pages 717-718. ( 1 )]

EXTRACT FROM REPORT OF MAJ. QEN. LAFAYETTE m'laWS, C. 8. A., DATED JULY 20,

1862.

Lieutenant Barry of the artillery had been for some days previous placed in charge
of a 32-poimd rifled gun, mounted on a rail car and protected from cannon shot by a

11

sloping roof in front, through which a poifhole had been pierced, and from rifle shots
on the sides by thick walls of wood lined with iron . His battery moved down the road,
keeping pace with the advance of the troops, and by his fira annoyed the enemy
whenever the range would allow.

[Battles and leaders of the Civil War, volume 2, page 373.(2)]

(Here will be found a report made by Maj. Gen. Wm. B. Franklin, United States
Army, describing the approach of the railway battery used at Savage Station.^)

[Same reference, page 374.(2))

(Here will be found a sketch showing the opposing forces at Savage Station and the
marked location of the railway battery.)

Gen. Joseph L. Brent of the Confederate Army mentions in his book
''Mobilizable fortifications" (3), first published in 1865, and repub-
lished in 1916 by WiUiams & Wilkins Co., Baltimore, that a 32-
pounder gun was mounted on a standard flat car and operated at a
point called Savage Station on the Richmond and York River Rail-
way. To quote, he says:

However, it was my fortune to witness perhaps the first fire that was ever delivered
in actual combat from an armored railway wagon.

During the American Civil War, in 1862, the Confederate authorities prepared in
Richmond a railway battery armored with railroad iron and carrying a 32-pbuiider
gun in front of the engine. The iron shield only covered the front of the battery, and
was pierced by an embrasure, but the sides and rear were unprotected.

When, in June, 1862, Lee made his flank movement against McClellan, one of the
Seven Days' Battles was delivered on the line of the Richmond and York River Rail-
way, at a point called Savage Station.

The iron railway battery was sent out on this road from Richmond, and Maj. Gen.
MacGruder, commanding the C/onfederates at Savage Station, ordered this battery to
advance and fire on the enemy.

It moved, propelled by steam, down the track, and passed into a deep cut, and
from this cut opened with its 32-pound gim, and burst its shell beyond the first line
of the Federals, and over the heads of their reserves, forcing them to shift their
position. '

About the same time the skirmishers of the opposing forces became engaged and the
lines of battle were deployed, resting on the right side of the railway.

The Union line was a little beyond the cut from which the itdlway battery fired,
and at right angles to it. If the battery had advanced it would have completely
enfiladed the Union line at short range, and must have broken it; but owing to the
fact that the sides and rear of the battery were open and exposed to the fire of the
sklrmiBhers, and to the further fact that the field of fire of the gun was limited by its
embrasures, the battery could not advance; and as the skirmish fire approached, it
withdrew. If guns had been moimted ''en barbette'' and the gunners and machin-
ery protected by only bullet-proof armor, and if there had been half a dozen such bat-
teries, they could have easily broken the Federal line of battle and have cut off their
reserves, laige numbers of which were stationed on the left of the track.

Particular attention is invited to Gen. Brent's hook. During the
Civil War he had been particularly impressed with the. effectiveness
of the Union gun boats operating on the larger rivers and in the
bayous at the mouths of the smaller rivers, especially in Louisiana,
Alabama, etc. He was thoroughly convinced of the futility of forti-

12

fying inland cities against siege by means of masonry forts, etc., and
was much impressed by the effectiveness of the Union gunboats just
noted, with the possibilities of fortifying and protecting any large
railway center by means of artillery of all calibers mounted on rail-
way carriages. Some time before 1870, while in France, a discussion
that he had with reference to this scheme of fortifying inland cities
came to the ears of Napoleon III, who called Gen. Brent into a con-
ference with reference to the practicability of his scheme in fortifying
Paris. Napolean was so much impressed with its possibilities that
he detailed several officers to conduct Gen. Brent on a tour of inspec-
tion of the fortifications of Paris. These officers were likewise
impressed with the possibilities of the scheme and submitted to
Napoleon a report recommending its adoption. This report was
forwarded by Napoleon to his army staff and was quite unfavorably
received; as a consequence the plan was rejected. Gen. Brent
discusses the Franco-Prussian War of 1870, commenting particularly
on the sieges of Metz and Paris.

3. William P. Brady's Civil War Pictures contain several excellent
photographs of two designs of artillery that were used by the Union
Army in their siege of Petersburg in 1864. One of these guns, plates
2 and 2A, was a 13-inch muzzle-loading mortar, 2.7 calibers in length.
This mortar weighed 17,000 pounds, used a spherical shell weighing
220 poimds, apd a powder charge of 20 pounds. The records available
indicate that this mortar had a range between 3 and 4 miles and did
effective work in the siege. It will be noted in plate 2 that the car
on which the mortar is mounted seems to be made up of two standard
trucks on which an improvised platform has been placed. It is
understood that this carriage failed after the mortar had been fired
several times and that thereafter the practice was to transfer the
mortar and its platform, as shown on plate 2A, from the railway car
to a more solid foundation. This railway mount was called '*The
Dictator" and *'Petersb\irg Express." On plate 3 is shown another
mount photographed by Brady which in his records is also de-
scribed as having been used in the siege of Petersburg.

4. Another reference to what was likely though not certainly the
13-inch mortar discussed before is given in Professional Papers,
Corps of Engineers, No. 14, Siege Artillery in the Campaign Against
Richmond, by Bvt. Brig. Gen. Henry L. Abbott, United States Army,
1868 (5). The follovring is quoted from page 23, referring to the
campaign of 1864:

The great weight of the 13-inch mortar (17.000 pounds) rendere it difficult to move
and some satisfactory experiments were made with a novel platform. An ordinary
railroad platform car (eight wheels) was strengthened by additional beams tied strongly
by iron rods and was plated on top with iron.

-a

r

16

The mortar was placed upon this car (top of mortar 9 feet ahove track), and run
down on the City Point Railroad to a point near our lines where a curve in the track
afforded facilities for changing the plane of fii;e by advancing the car or drawing It
back. The mortar fired with 14 pounds of powder, recoiled less than 2 feet on the car,
which moved 10 or 12 feet on the track. The effect of the charge was taken up with-
out damage to the axles, even when the full allowance of 20 pounds of powder wap
used. This mortar, whose shell would crush and explode any ordinary field maga-
xtne, excited dread among the Confederate gunners, and was effective in inducing
their enfilading batteries on Chesterfield Heights to discontinue fire upon the right of
our line. ItB practice was excellent. At the Battle of the Mine, as reported by three
different observers stationed at different points, the explosion ol one of its shells blew
a Confederate field gun and carriage above the parapet at a range of about 3,600 yards.

Of. course with this platform the plane of the fire must be nearly parallel to the track
or the mortar will be dismounted, but by placing the car on a curve a very considera-
ble traverse can be secured without diflSculty.

The fact that Gen. Abbott mentions that this mortar which
operated against Richmond was mounted on a standard flat car
seems to indicate that it is not the same mortar that was photo-
graphed by Brady at Petersburg. The mortar carriage shown in
plate 2 is apparently improvised, the two trucks being practically
together.

5. In the ''Revue d' Artillerie/' volume 7, 1876, page 8, (6) a
railway mount used by the British service for proof work is described.
This carriage consisted of a rigid body of steel mounted on two six-
wheel trucks; there was no recoil mechanism. The following data is
given with reference to weights and dimensions: Weight of truck
with gun carriage, 38 tons; weight of powder charge, 108.9 kilograms;
muzzle velocity, 472.4 meters per second ; recoil length, 11.63 meters
up a 2.5 per cent grade.

6. Mention is made of a proof mount employed by the British for
a 26-ton gun in the proceedings of the Institute of Civil Engineers,
November 22, 1881, (7) under the discussion of the effect of recoil on
field carriages. This mount consisted of an ordinary coast type of
gun lift carriage mounted on two four-wheel trucks and is similar in
many respects to some of the Schneider mounts, improvised from
coast defense guns and used in the European War. Apparently this
mount was used as a rolling recoil mount and was not anchored to
the track. In the discussion, it is mentioned that the total recoil of
the gun on the carriage was 3 feet and that the movement of the
railway car began when the gun had reached its maximum velocity,
i. e., after a recoil of about 6 inches.

7. In the minutes of the proceedings of the Royal Artillery Insti-
tute, volume 15 of 1888, (8) there is an article dealing with experi-
ments made at Delhi, India, January, 1886, with a 40-pounder
breech-loading gim on a wooden naval carriage. The railway cars
on which this carriage was successively mounted were of 1 meter

17

<

gauge. The naval carriage mentioned above, carried the gun
directly with no recoil mechanism. Two types of cars were em-
ployed; the first was a light four-wheel car, 6.5 by 13.5 feet, and pro-
vided with a wrought-iron underframe. The weight of the car,
light, was 2.87 tons and with the gun, 9 tons; the second was an
eight-wheel car 7 by 25 feet and was constructed entirely of wrought
iron. The weighf of this gun was 5.4 tons. Wood wedges were put
under the car against the sleepers and props were also employed.
The guns were fired at right angles to the track. Firing proved both
of these arrangements to be unstable, although the eight-wheel car
jumped much less than the four-wheel car. In subsequent experi-
ments the car was loaded with rails to a total weight of 19 tons, and
the gun was placed over the forward truck with its center line 7 feet
0.5 inches above the rail. This appeared to give satisfactory re-
sults with the eight-wheel car. Tlie truck springs were deflected
0.437 inches, but the wheels were not lifted from the track. The
conclusion stated in this article is that the scheme is suggested as
satisfactory, although much would probably be gained by clamping
the mount to the rails. It is mentioned that the oscillation of the
car is so great that a man could probably not stand on it during
firing.

8. A description is given of experiments made by the British in
1896 in the "Revue d' Artillerie," volume 50, page 34, of 1894, (9).
These experiments were made on the railroad between Brighton and
New Haven with a train of armored cars on which field .guns were
mounted. It was possible to fire these gims in a]l directions. The
cars were solidly fixed to the rails by special brakes and remained
stationary even when the gims were fired in the direction of the
track. In certain French publications, (10) mention was found of
the fact that both the Krupp and Skoda works conducted experi-
ments between 1890 and 1900 on the use of the light field guns mount-
ed on railway carriages.

9. The first concrete results of the interest of the French Technical
Service in railway artillery appeared in the eighties when Gen. (then
Col.) Peigne became its advocate. The first papers appeared in
about 1883, and his work culminated in experiments carried on with
the 155-millimeter Howitzer in 1888, and the construction of materifll
developed from these experiments for the coast defenses of Denmark,
plates 4 to 7. About the same time the St. Chamond Co. developed a
disappearing carriage on railway wheels for the defense of fortifica-
tions and coasts. Carriages of this type mounting 120-millimeter
guns, plate 8, were furnished the Swiss Government for the defense
of the Rhone Valley.

10. The second actual employment of railway artillery in warfare,
of which record is available, was by the British in the South African

ARRIAOE OF 155 MM. HOWITZER ON RAILWAY MOUNT.

CUM CARRIAQE OF THE 120 MM. RIFLE ON RAILWAY UOUNT.

»3

23

War in 1899-1900. One reference to the guns used in this war is
found in the lecture given by Capts. Percy Scott and H. A. Limpus
in Hongkong, and published by the Hongkong Daily Press on
June 13, 1900, (11). In this lecture mention was first made of the
4.7-inch gun mounted on a railway carriage and used at Lady-
smith. The mounting for this gun consisted of four pieces of timber
14 feet lohg by 12 inches square, plate 9, placed in the form of a cross.
The ordinary ship mounting was arranged on the center of this and
held in place by bolts passing through U> a steel plate underneath.
The gun carriage was set over the "spindle of this mounting and
screwed down by its clip plate. The railway car on which this cross
of heavy wood beams was placed was an eight-wheel drop frame flat
car. The lecture further mentioned that while the army was oper-
ating in the Spion Kop direction. Gen. Barton who was active at
Chievely wanted a 4.7-inch gun mounted on a railway carriage to
shell a new position that had been occupied by the Boers. There
was no time to make a new mounting, so one of the platform mount-
ings similar to those sent to Ladysmith was placed on a low truck
and secured down with chains. The ends of the transverse timber
were cut off to allow the carriage to pass through the tunnels.
Very little recoil was transmitted to the track and the gun could bo
fired across the track satisfactorily. The mount was arranged for
removal from the car and installation on. the ground by the use of
supplementary beams, replacing those partially cut off. Three
more mounts like this were made up and used against the Boers in
the attack at Pieters Hill.

11. The limit of development of this type of artillery prior to 1914
appears to have been the 200-millimeter howitzer mounts, plate 10,
constructed by the Schneider Co. for the Peruvian Government in
1910- These represented really very little advance over the ideas
of Gen. Peigne as worked out by Canet over 20 years previously.

12. The invasion of Belgium in 1914 gave the first intimation of
the great German 42-centimeter mortars. There is evidence to indi-
cate that some of these were mounted on railway carriages. Others
were mounted on wheeled carriages. A little later the French impro-
vised a mount for their 305-millimeter gun.

13. In the Engineer for September 3, 1915, 12 photographs are
given showing 4.7 and 6 inch guns, mounted on platform cars and
with shields over them. A photograph is given also of a 12-ponnder
mounted on the car. These mounts were manufactured and used in
South Africa. All of them were improvised from available guns and
locomotive and tender trucks, except in the case of the 12-pounder
mount, for which a standard two-truck car was employed. These
mounts were provided with swinging arms and jack screws extending

if

S|

27

from the arms, similar to the Schneider 200-millimeter howitzer and
the American original model 1918 8-inch moimt.

14. The character of development of railway artillery is perhaps
best illustrated by the following table of mounts already mentioned,
as well as of mounts developed during the European war.

No.

Caliber.

Type.
Mortar

Make.

Date.

Approxi*

mate

muzzle

energy.

1

13-iiich

Improvised. Civil War

1864
18^-1890
1889
1910
1914
1915
1917
1918
1918

meters.
300

2

ISS-mm

Howitzer

Schneider-Canet

St. Chamond

270

3

120-mm

Gun

368

4

20O-n)»n .

Howitzer

Schneider

Krupp

930

5

420-mm

305-inm

Mortar

4,900

6

Gun

St. Chamond

Schneider

11,200
17,860
19,600

7

53(MnTn..

Howitzer

8

14-iiich

Rifle

United States Navy

United States Army (design only)

9

16-inch

do

37,600

1

15. A comparison of the fourth, fifth, and sixth items above shows
the enormous increase in power of railway artillery which took place
at the beginning of the war. The seventh and eighth show the
heaviest pieces actually constructed and used and the last is the
heaviest mount on which design had been perfected. Thus the
period of the war has seen a forty-fold development in the power of
railway artillery. It is the high points of this development which
will be traced in the succeeding sections.

SECTION 1.
CLASSDICATION OF TYPES OF RAILWAY ARTILLERY.

16. The various types of railway artUlery may be classified to
advantage by the characteristics of three chief factors in design —
traverse, recoil, and anchorage.

17. Before going into the details of these classifications it should
be emphasized that a very large number of the mounts described in
Volume II and used for illustrations below were designed and con-
struct^ under the greatest possible pressure, so far as time was
concerned, and from whatever materials happened to be available.
In consec|uence, many features found in them were the result of
this pressure, and in many cases were inherently undesirable. In
the foUowing, an attempt is made to point out, as clearly as pos-
sible, these features which were the result of such forced improvisa-
tion.

CLASSmCATION ACCORDING TO METHOD OF TRAVERSE.

18. Traverse is obtained in railway mounts by one of three methods.
These are: (1) By moving the mount along a curved track or epi
(nontraversing mount); (2) by rotating the railway carriage about
a real or imaginary vertical axis (car traverse) ; and (3) by rotating a
top carriage rotable with respect to the car (top carriage traverse).
For illustrations of these methods see plate 1 1 .

19. NoNTEAVBESiNG MouNT. — On this type of mount no pro-
vision is made either on the gun carriage or the railway car body
for traversing the gun; it can be pointed in azimuth only b}' moving
the entire ;mount along a curved track.

20. The most striking examples of this t^'pe are the so-called
Schneider mounts on which the gun is either supported on the side
girders of the car or on a gun carriage that is capable of linear motion
only, and that in a direction parallel to the side girders. The first
arrangement (gun supported directly on side girders) is illustrated on
plates 12, 13, 14, and 15, and the second (gun on recoiling top carriage)
on plates 16, 17, IS, and 19.

(29)

30

NON reAVEfeSING MOUNT

CAR TRA\/ERSING MOUNT

TrjiTE 11

1.

.^ _j

-Z-^::^

-^

TOF^cA^eMGE TB^/fes/m MOU/^r

CLASSIFICATION OF RAILWAY ARTILLERY ACCORDING TO METHODS OF

TRAVERSE.

181768—21—8

SB

37

<
•J

39

21. Car-Tba VERSING MouNT. — The distinctive feature of this
type is the provision which is made for traversing the entire car
body. The gun is supported in the car body, either directly on rigid
trunnions, or through a cradle or top carriage without traverse, and
it can be moved in azimuth only to the extent that it is possible to
traverse the car body. As a rule this traverse is obtained by a slight
movement of the car bod}^ on the trucks, giving a few degrees on
each side of the center line. Other mounts of this type, however,
are provided with an elaborate center plate with traversing rollers
and are capable of large traverse or even of all round fire. The
latter type, and sometimes the former as well, re([uire an elaborate
foundation and are generally provided with a large center pin which
takes the horizontal component of the shock of recoil. Car-traversing
mounts affording limited fire are illustrated on plates 20, 21, 22 and
23, and one allowing large traverse or all round fire is illustrated on
plate 24.

22. Top Carriage Traversing Mounts. — The distinctive fea-
ture of this type is the provision of a top carriage rotable with
respect to the car body. The amount of traverse varies on the
different designs in use from 10 to 360 degrees. In each of these
designs, with the single exception of the American 16-inch howitzer,
model 1918 MI, either a more or less elaborate firing platform or
some arrangement of outriggers is required. Top carriage traversing
mounts affording limited fire are illustrated on plates 25 and 26,
and those affording all round fire are shown on plates 27, 28, 29, 30,
and 31.

23. Discussion. — The nontraversing mounts are all, to a cer-
tain extent, improvisations. The French term them *'affuts de
circonstance. " It is the concensus of opinion that, where time and
facilities permit, a small amount of traverse at least should be given,
so that the gun may be trained closely in azimuth. The distinction
between the other two types seems to be more essentially on the basis
of caliber and muzzle energy. The top carriage type traverse is
easily applied with the smaller guns while the car-body traverse is
reserved for the heavier and higher powered ones.

CLASSinCATION ACCORDING TO RECOIL SYSTEM.

24. Recoil is taken up on railway artillery by allowing the displace-
ment of the mount or some portion thereof and retarding this motion,
(Characteristic provisions are made for bringing the moving part
back to its original position. Such artillery may be classified in
accordance with the extent of this recoiling portion into the following
well-marked systems: (1) Cradle recoil, top carriage recoil, sliding
mount recoil, and rolling mount recoil. See plate 32 for illustrations
of these types. The means of retardation and of return to batter}-

48

\

2

00
CI

I!

<

\

\

«

Nkl

I:

I

f

>e?cA

-s. ••

>

ft

T

2-lh

3

Breech I
jpcninyGear^A

49

H
C4

P4

n
3

O

o

51

Pl>TB 32

r— ^31

^ J ^ ^ ^ J ^

2

C/eADLE leECOtL

TOPCAf^/^MGt RECOIL

SLIDING BECOIL

r-,,^

eOLUN& RECOIL

CLiLSSmCATION OK RAILWAY ARTII.LEItV ACCORDISO TO RECOIL SYSTEMS.

52

are various but each is more or less characteristic of one of the above
types and they will be described in detail und^ the appropriate
heads.

26. Cbadle Recoil. — ^The characteristic of this type is that the
gun only recoils, moving backward along the Une of fire, in a sleeve
or cradle. The gun is retarded and brought to rest by means of
hydraulic buffers, or dashpots, attached to the cradle, and with
pistons which are rigidly attached to the gun. Return to battery
is obtained by heUcal steel springs, or by the pressure of air in a
pneumatic recuperator cylinder, in which increased compression is
produced by the recoil. The cradle is provided with trunnions and
the cradle and gun are swung in the trunnion bearings of the carriage.
For examples of this type of recoil system see plates 33, 34, 35 (spring
counterrecoil) and plates 36, 37, and 38 (pneumatic counterrecoil) .

26. Top-Cabriaoe Recoil. — ^The characteristic of this type is
that the gun is carried in a top carriage, supported by wheels on fixed
rails. The gun and carriage recoil together in a fixed direction along,
these rails. Recoil is restrained by hydraulic buffers and return to
battery is obtained either by gravity, through the use of inclined
rails, up which the gun recoils, by springs, or on some improvised
mounts, by rubber bands. An air recuperator might equally well be
used, but no example of such a combination is known. Examples
of this type with gravity counterrecoil are shown on plates 16 and 39,
and witii springs or rubber bands on plates 40 and 41.

27. Sliding Recoil. — ^The characteristics of this type are that the
gun, car body, and trucks recoil together, the car body sliding on a
special set of girders incorporated in the track. The car body is' pro-
vided with wooden crossbeams or *' sleepers'' which are jacked down
on the track girders in such a way that about one-half the weight
of the mount is transferred to them from the truck. The resulting
friction thus created absorbs the energy of recoil and brings the mount
to rest. This recoil varies from 1 to 2 meters. All of these mounts,
with two exceptions — the American Army 14-inch design and Italian
381-millimeter — are of the nontraversing type and must be fired from
a previously prepared curved firing track or epi. Counter-recoil,
or the return of the gun to firing position, is obtained by jacking up
the sleepers, thus returning aU of the weight to the trucks and rolling
the entire mount forward by the amount of the recoil. This is usually-
accomplished by gear trains and handwheels^ through which two or
more pairs of wheels may be driven and exact adjustment of the
mount on the track obtained. In the heavier mounts an electric
motor drive is employed, and in other cases a gasoline winch has been
used with success. Even with the heaviest guns ordinary car pushers,
applied in sufficient number, have served as an emeigency method
of moving the gun back into battery. Ebcamples of this type of
mount may be found in a wide variety of calibers on plates 12, 13,
42, 43, and 44.

53

flu

54

CC

<

55

09
H

S6

RECOIL (HYORO-PHBUUATIC) SYBTEU OF THE OERMAN IW-MH. OVN.

58

3

i"

A. J
' 1 ^"

1

65

28. Rolling Reicoil. — ^The characteristics of this typo are that
the gun, car body, and trucks recoil together, rolling backward on
standard tritck, the brakes being set to bring the mount to rest. Re-
turn to battery is obtained by a winch mounted on the forward truck;
the cable is attached to the track some distance ahead. Mounts of
this type recoil a distance of from 30 to 50 feet. The use of this type
of recoil alone is not practicable, as the vertical component of the force
of recoil would be too great for the truck springs to stand. In all ex-
isting types the gun is mounted in a cradle, thereby giving a double
recoil system. This type of mount is usually provided with car trav-
erse, giving a small amount of movement in azimuth, and must, of
course, be fired from a curved track to get a greater movement.
Plates 20, 21, and 45 show examples of this type of recoil system in
combination with a cradle as noted above.

29. Combinations. — ^These various systems are found in several
combinations, also, in existing mounts.

Cradle-sliding recoil- is found in the Schneider 520-millimeter how-
itzer, plate 46.

Cradle-rolling recoil is found in the British 12 and 14 inch rifle
mounts and the United States Navy 14-inch mount, Mark II, plate 45.

Top-carriage-sliding recoil is found in the Schneider 270-miUimeter
howitzer as shown on plate 47.

30. Discussion. — Cradle recoil with air recuperation is probably
the highest development in recoil systems.

31. Top-carriage recoil was devised 40 or more years ago for coast
defense guns operated at low angles of elevation. It is not well
suited to firing at high elevations. This system is found only on rail-
road mounts which have been improvised from available coast de-
fense materiel, and there seems no great reason why it should be con-
sidered for new design.

32. The sliding recoil system is worthy of considerable considera-
tion. Improvised originally to provide for heavy guns, a mount
which could be manufactured in a minimum of time, it has shown a
ruggedness and convenience in service that have recommended it very
highly. There are certain limitations on the use of this type of
mount. Time of operation and lack of traverse make it unsuited to
small guns. The enormous trunnion forces which must be taken
care of likewise make it unsuited for the very largest howitzers firing
at high angles.

33. The cradle-rolling recoil combination is, like the sliding system,
unsuited to small guns, because of the lack of traverse and time of
operation, but it represents a very satisfactory system for the heaviest
type of guns.

69

CLASSmCATION ACCORDING TO METHOD OF ANCHORAGE.

34. Railway mounts may be classified according to the character
of the structure required to transmit the force of recoil from the gun
to the earth, as follows:

1. Mounts requiring no structure whatever.

2. Moimts requiring a track platform; i. e.^ a structure built

above and more or less without disturbing the track.

3. Mounts requiring a groimd platform; i. e., a structure

fitting into and imdcr the track.
These schemes of anchorage are illustrated on plate 48.

35. Mounts Requiring no Structure. — ^The only mounts of
this type are those with the combination of cradle and rolling recoil
mechanism, which fire directly from standard track. They are
provided with car-body traverse, giving a small movement in azi-
muth, and must be fired from a curved track or epi to get greater
traverse. The British 12-inch and 14-inch rifle mounts, the American
14-inch naval mount, Mark I (for firing at angles under 15 degrees)
and Mark II (for elevations as great as 40 degrees), the 16-inch
howitzer, model 1918 MI (American), and German 38-K;entimeter
are examples. These are shown on plates 20, 21, 45, and 364.

36. Mounts Requiring a Track Platform. — In mounts of
this type a part of the vertical component of the force of recoil is
taken by girders, pads, or floats placed on the ground or on top of the
ties, and the horizontal component either by friction, or through rail
clamps, guys, or struts. The Schneider sliding mounts are examples of
the type in which the horizontal component is absorbed by friction.
This type can have only very Umited car traverse (a maximum of
5 d^rees), sinc« a greater traverse will result in an abnormal dis-
placement of the track. They are shown on plates 12, 13, 42, 43,
and 46. The 194 and 240 milUmeter Schneider mounts and the
British 12-inch howitzers and 9.2-inch guns belong to the class em-
ploying raU clamps or guys. They have top-carriage or cradle recoil
and in some cases afiford aU-round fire. These are shown on plates
16, 41, 49, and 50. The American 8-inch gun, plate 30, and French
240-millimeter gun, plate 27, belong to the class using struts as well
as track platforms and both permit of all-round fire.

37. Mounts Requirino a Ground Platform. — ^The character-
istics of this type is that an extensive anchorage, the instaflation
of which involves tearing up the track, must be constructed before
firing can take place. This foundation may consist simply of very
heavy timber pads and floats, as with the St. Chamond 340 and 400
millimeter and the American 16-inch mounts, or it may be a very
elaborate and specially constructed steel or concrete base, as with
the BatignoUes, and the German 280 and 380 millimeter mounts.

70

Plate 48

^3"

^f^Cif^Pif^

J V.

OQQQOO

/^O SPECiAL /INCHOeAG^E

^,. 'Ia*/'T

■j\ T ''•7. '• 1 1 t*- 7- y^ijj'

TTRycT/r PLATFORM ANCHORAaE

\V^^iM<>.^h\

aEOUND PLATFOeM AA/CHOeAGE

CLASSIFICATION OF RAILWAY ARTILLERY ACCORDING TO METHOD <>.•

ANCHORAGE.

73

In almost all cases only a very limited traverse is possible. The
German gims give all-roimd fire. The above noted moimts are
illustrated on plates 51, 52, 53, 209, 54, 24, 55, 56, and 57.

38. Discussion. — ^Two points are intimately connected with the
type of anchorage employed, viz: (1) The time necessary to get
into action and withdraw the moimt from position, and (2) the amoimt
of traverse allowed. The former is important in effecting a surprise
and in withdrawing to avoid enemy counterfire. It varies from
almost nothing on the first type, after the epi is constructed, to per-
haps an hour on the best of the second type, and then up to three or
four days on the very elaborate mounts of the ground platform type.
As to traverse, the first type permits any desired amount, limited
only by the extent of the curve, and is suited to the largest calibers;
the second likewise permits of a traverse limited only by the extent
of the curve for heavy guns with sUding recoil and all-ro\md fire for
the lighter and mediimi guns. The third type usually permits of
only limited traverse (10 to 15 degrees) for the heaviest guns and all-
round fire for medium calibers. It might be added that rail clamps
and guys are devices adopted with the lighter guns and are to be con-
sidered improvisations; struts have proved more efficient.

76

C2

i

ircTURAL STEKL EMPLACEMENT FOB 28a-MU. <

CONCRETE EHPI^CEMEN'T FOR UERHAN 28a-MU. ^
181768—21 fi

SECTION 2.
SCOPE OF UTILITY OF RAILWAY ARTILLERY.

39. Experience with railway artillery in the present war has been
almost entirely in land warfare, so that the following is written pri-
marily to cover that field. A final paragraph is added, however,
covering its use for coast defense.

40. In considering the scope of utility of railway artillery in land
warfare, several general limitations should be borne in mind. It is
the heaviest, most powerful, and most costly of all artillery and for
this reason, it should be exposed to a minimum of danger of destruc-
tion and capture, and should be used only when heavy mobile artil-
lery will not suffice. It is hence used only for offensive operations
and special service, being organized as a separate reserve and not
attached to any one army. Except in sectors of a front, which have
been quiet for a long while, standard gauge railway lines can not
easily be maintained closer than from 5 to 10 kilometers to the line,
hence heavy railway artillery can not be operated closer to the line.
Further, experience has taught that it should be kept out of the
range of the field guns and smaller caliber heavy guns. In some
cases, as in the American St. Mihiel offensive of September, 1918, the
railway artillery was run up to within 3 kilometers of the front lines.
This point is discussed more fully in section 7.

41. Within the limitations noted above, railway artillery is util-
ized for the following purposes:

Destruction.

Counter-battery work.

Interdiction.

Distant bombardment for moral effect.

42. Destruction. — Fire of destruction as executed by railway
artillery has for objectives in general order of range:

(a) Permanently fortified works, as concrete turrets, observa-

tion posts, sentry towers or observation posts, concrete
rampart shelters, concrete cantonment shelters, gun
casemates, flanking casemates, and flank trenches, con-
crete conmiunication galleries, troop shelters, machine
gun and antitank forts.

(b) Bridges, culverts, cuts, and fills.

(c) Balloons and towers used for observation and located at

long range.
id) Centers of supply and distribution, as railroad yards, sup-
ply depots, ammunition dumps, industrial centers, etc.

(81)

82

Except in the case of (c) above, it is obvious that, for the purpose
of destruction the maximum plunging fire is desirable and that the
pieces that should be used are howitzers and mortars, so long as the
necessary range can be obtained with them. Objectives of class (d)
are ordinarily located at such ranges that guns must be used, It is
evident that relatively large explosive charges and perhaps numerous
shots wiU be required for this purpose and, except in the last case,
very high accuracy of fire is essential.

43. Counter-battery work. — ^Under the heading of counter-
battery work is ordinarily included the destruction of only such
enemy batteries as are so distant as to be beyond the range, or so well
protected as to be beyond the destructive power of the army artil-
lery. Occasionally it may be imperative that certain batteries be
put out of action in much less time than would be possible with army
artillery that must be moved up from some other locality. In these
cases, obviously, railway artillery capable of aU-roimd fire should be
used.

44. Circumstances demand ordinarily cannon of long range and
medium caliber for this work and mounts provided with facilities for
the most rapid and universal service: TTiis would include mounts
whose firing platform requires a very small time for installation, and
mounts provided with traverse for all-round or nearly all-round fire.

45. Interdiction. — The objectives of fire of interdiction are lines
of communication, roads, raih-oads, telegraph, and telephone lines,
etc. It may be very desirable to keep a section of a certain railway
line out of commission. It may be desirable likewise to shell certain
sections of very important roads over which supplies and men must
be moved. At night a few shells per hour may be sufficient to seri-
ously interrupt traffic. During the day when observation is possible
more active shelling may be carried out. Guns of long range, me-
dium caliber, and large traverse are preferred for this work. The
practice has been to carry out fire of interdiction only when it will be
most effective, i. e., immediately before, during, or immediately after,
an attack.

46. Distant Bombardment for Moral Effect. — ^The objec-
tives of bombardment for moral effect are large centers of populatiiDn
long distances behind the lines. The aim is to destroy any sense of
security which the distance from the front lines may give the civilian,
to undermine the spirit of the army by weakening the morale of the
civil population, and to interfere to the maximum with the adminis-
tration of the war.

47. The characteristic of first importance for this kind of fire is
extremely long range, 100 to 120 kilometers or so. Difficulties of
construction seem to limit the caliber of these long guns to about 240
millimeters. Little or no traverse is required. At least one shot per

83

hour is considered necessary to produce the desired effect, and abso-
lute r^ularity in the bombardment is necessary for the maximum
effect on morale.

48. The single example of action from a gun of this sort was the
bombardment of Paris. The writer was in Paris for several days at
a time on four occasions during the bombardment by the long-range
gun. On some days projectiles arrived every 15 minutes from about
8 a. m. to 5 p. m. On other days the bombardment would begin
promptly at 12.40 noon. On the first day of the bombardment, on
March 23, 1918, there was considerable confusion, more because the
people thought they were being bombed by airplanes from a great
height than from any other apparent reason. From then on the
effect could not be determined with any certainty. There seemed
to be as many people on the streets during the days of most active
bombardment as on quiet days. When a projectile would burst the
people in that vicinity would appear startled but not frightened and
always some would hurry in the direction of the explosion to see the
damage. All of the trains going west or south from Paris were
crowded in those days, but there was no evidence that the departure
of those people who lived in Paris was not caused by the steady ap-
proach of the Germans and the possibility of the capture of Paris
rather than through panic or fear of the bombardment.

49. The damage done by the? long-range projectiles was never very
great. '. f one burst in a building its effect was not always evident
outside. One shell hole seen in the Gardens of the Tuilleries was
about 4 feet deep and from. 10 to 12 feet in diameter. Further, the
dispersion of the guns was so great that two projectiles would land
within a kilometer of each other only by chance. Judging from the
small extent of damage and the doubtful effect produced on the civil
population, it would seem extremely doubtful if such bombardment
as this is nearly as effective either from the standpoint of material
damage or e^ect on morale, as an equal investment in bombing
planes and bombs. A published statement of the work of aeroplanes
and of the long-range guns is given as an appendix to this report.

LO. Assignment of Mounts to Various Duties. — The follow-
ing rules govern the assignment of types of railway artillery to the
various duties detailed above.

(a) Calibers of pieces are assigned according to the resistance

of the targets.

(b) Types of pieces (mortar, howitzer, rifle) are assigned ac-

cording to range (see later discussion) .

(c) Types of mounts (as regards provision for traverse, an-

chorage, etc.) are assigned according to the number of
different targets to be fired upon and the time available
for preparation and change of position.

84

Following is a discussion of the significance of each of the above
rules.

51. Assignment op Calibers According to Resistance of
Targets. — Railway artillery is far too difficult to manufacture and
too valuable to be used except at the nearest possible approach to a
100 per cent efficiency basis. It would be most unwise to undertake
to destroy certain heavy concrete fortifications with 194-millimeter
howitzers, involving the expenditure of a great amount of ammu-
nition and considerable wear of the guns and perhaps, after all, not
accomplishing satisfactory results, when a few shells from a 320-
millimeter howitzer would accomplish the desired results. Further,
it would be criminal to use 320-millimeter howitzers on machine-gun
forts, sentry towers, etc., if smaller howitzers were available.

52. In the region northeast of Soissons the Germans were using in
1917 some old quarries very similar to a series of mine galleries,
some 90 feet or more under ground, as troop shelters. The French
were aware of this fact, and in preparing for their offensive in this
region, decided to attempt the destruction of these shelters. 400-
millimeter howitzers were assigned to the work, and with their great
weight of projectile, high angle of fire, and consequent nearly vertical
drop of projectile, accomplished very satisfactory results. The shells
penetrated the overlying earth and chalk to a depth of about 50 feet
and on bursting caused great sections* of the roofs of the galleries to
drop, imprisoning or killing the Germans.

53. Assignment of Types According to Range. — ^As with
resistance of target so with range, no more powerful gun should be
employed than is absolutely necessary. Wear, first cost, and time
of manufacture are all much less on the shorter and less powerful
guns. The following table, which is taken from French experience,
shows clearly the relative rates of wear at the various ranges. It is
evident that to use a 300-round gun on objectives that could be de-
stroyed as effectively by from 2,000 to 4,000 round howitzers would
be nothing short of criminal.

Oun.

Caliber j ««„». . Life,
length. ; ^*"*^- rouncfs.

I

280-niIllimeterhowiUor 1.) 11,490; 4,000

24-Ghowltwjr 20 13,700 3,000

240-miIlJmeter T. R. 1903.
240-millimeter model 1893-6.
305-millimeter model 1893-6.

27
40
40

16,800 2,400
23,200 600
27,000 300

In regard to the other two points, cost and time of manufacture,
only about half the time is required to manufacture a howitzer as
to make a gun of the same caliber, lighter machinery may be em-
ployed, and the cost is even less than half.

85

54. Relative Wear op Guns. — The accuracy life of any gun is
greatly increased if it is fired with reduced charges and consequently
reduced muzzle velocities. The following British table of equivalent
charges illustrates this point:

Equivalent charges y showing relative wear of guns with various charges.

[Fall charge taken as 100 per cent wear.]

No. of
parts of
charge.

IS-toch
howitzer.

12-Jnch
howitzer,
1 and 11.

0.2-inch
howitzer.

8-iiich
howitzer.

(^inch
28cwt.

6-inch
SOcwt.

4.5-inch
howitzer.

6
5

4
3
2

1

1.000
.62
.38
.27
.17
.13

1.00
.48
.27
.14
.09
.06

1.00
.22
.06
.05
.04

i.66 *

.30
.17
.07

1.00
.14
.07
.04

1.00
.15
.07
.03

1.00
.24
.06
.03

55. In view of these facts it would seem best to use the shortest
gun and the lowest charge and muzzle velocity possible. The
closest point at which it is possible safely to locate the piece deter-
mines, of course, the range. Ideal practice, therefore, would be to
use the shortest piece of the required caliber, which at its most
favorable elevation can realize this range. If the nearest piece to
the ideal which is available has a range materially greater than that
required, then it should be fired with as much of a reduced charge
as possible.

56. In this connection it is, of course, understood that the designer
and builder and the users of the gun will probably never agree on
the question of their proper use. A prime and proper desire always
in the mind of the user is for greater and greater range. The
designer and builder dislikes to see his machine abused and wishes
to keep the muzzle velocity as low as possible.

57. Assignment of Types of Mounts According to Time
Available for Emplacement. — ^It is to be assumed, of course, that .
the caUber and type of gim required has first been determined in
accordance with the resistance and range of the target. With any
given type and caliber of gun there will ordinarily be found a series
of mounts, some of which afford no traverse, others limited traverse,
and still others all-roimd traverse. Some moimts require no anchor-
age, others require a simple arrangement which may be put in
place in an hour or less, while others use very elaborate emplace-
ments, requiring from two to five days to install. The principle
upon which mounts having various characteristics as to traverse
and extent of anchorage will be selected, is that the least valuable
gun and mount that can be made to satisfactorily accomplish the
desired results shall be used. This will permit the most valuable
mounts and guns to be saved for that special and emergency work
for which only they are adapted.

86

58. Ordinarily, arrangements for the use of railway artillery may
be made very deliberately. If there is plenty of time, the necessity
for the use of a cumbersome firing platform may not be a handicap.
There is no objection to having the men do the manual labor of put-
ting down a platform since, ordinarily, the battery commander may
be hard put to find enough work to keep his men busy and contented.
This should not be considered an argument for building such artillery,
however^ and indeed no battery or group commander with whom
the writer has talked would select 340 or 400 millimeter St. Chamond
mounts if he had the choice between these and 305 or 370 millimetei
Schneider mounts. However, if the Army possesses such mounts
and if time is available sufficient to construct the number of emplace-
ments required to cover all the objectives, then there is no objection
to the use of mounts having small traverse and elaborate firing plat-
forms.

59. For counter-battery work it is ordinarily necessary to move the
guns up and prepare them for action in a minimum of time, this
minimum being counted in hours (six or less). It is desirable, like-
wise, that it be possible to remove these mounts within a half hour
or less. In such cases, which are really those emergency cases noted
in the previous paragraph, the moimts affording wide traverse or all-
round fire and requiring not more than an hour for emplacement
will be chosen.

TABULAR CLASSinCATION OF RAILWAY ARTILLERY.

60. For convenient reference, tables classifying railway artillery
in accordance with the preceding are given below. The examples
here given are from practice.

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89

The platforms for the slidmg and French and American BatignoUes
mounts can be installed beforehand, and the gun can be run
up, fired, and brought back in a very short time. In the case of
the sliding type, the platform amoimts simply to additional girder
rails laid on the ties. Successful experiments have been conducted
in which the girder rails were attached to the sleepers of the mount
and slid on the ties. In such cases the operation of the sliding mounts
becomes almost as rapid as that of mounts firing without preparation.

RELATION OF RAILWAY ARTILLERY TO OTHER TYPES.

61. A consideration of the scope of utility of railway artillery
would be incomplete without a presentation of the relation between
this and the less powerful types — afield and heavy wheeled artillery.

62. If a set of rectangular coordinates be set up, with ordinates
representing calibers and abscissae representing ranges, then any
possible objective of artillery fire can be located in the field of these
coordinates, its position relative to the nearest available battery
location giving the range, and the character and resistance fixing
the caliber, plate 58.

63. A given type of gun may be represented on the above-noted
ordinates by a line joining the points representing the objectives it
can reach. Mortars, for example, with a characteristic muzzle veloc-
ity of approximately 300 meters per second, would be represented
by the line to the left on the diagram, joining all points representing
a range and caliber requiring 300 meters per second velocity to
realize them. In the same way the line at the bottom represents
long guns (muzzle velocity about 850 meters per second). Thus the
entire field of artillery (except trench artillery and long-range guns)
is included between the two exterior lines.

64. A given type such as field or heavy artillery is represented by
an area including all the points representing objectives for which
the various guns of this type of artillery are suitable. On the
diagram, plate 58, a line has been drawn, joining the points repre-
senting the heaviest field artillery guns, howitzers, and mortars. Thus
the area below this line and between the two limiting lines represents
the province of field artillery.

65. A second similar line has been drawn representing the upper
limit of heavy artUlery at the beginning of the war in 1914. The area
between it and the previous line therefore represents the domain of
heavy artillery. And, by consequence, the area above and to the
right of this line is the domain of railway artillery.

66. For Comparison, a line has been drawn through points repre-
senting the lightest railway artillery employed by the French. As
will be noted, it intersects the heavy artillery line, indicating that rail-
way howitzers were being used where heavy artillery materiel would
have served equally well.

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91

67. Developments during the war have, however, considerably
changed conditions. All along the line it has become possible to
moimt heavier artillery on mobile carriages and therefore the line
marking the upper limit of heavy artillery has advanced to the
position shown by the new curve marked 1918. This, of course,
restricts the field of railway artillery and means that still others of
the French railway moimts (240 and 270 millimeter howitzers) could
be replaced by mobile materiel.

68. The upper limit of the field of railway artillery is not yet
marked, as in other arms, by the limitations of the type of mount.
Any gun yet constructed can be mounted on a railway mount. The
limitation comes in a vertical direction from the resistance of the
most difficult objective to be destroyed. Certainly no objective
has yet been encountered which the 520-millimeter howitzer or even
the 400-miUimeter howitzer could not reduce. The opinion gained
from a general familiarity with the subject is that, in land warfare,
only very exceptional targets will require such calibers and 300f to
350 millimeters is ample for all ordinary purposes.

69. The upper limit of railway artillery in respect to range is also
fixed by economic rather than by physical limitations'^. Guns of
extreme range used in distance bombardment for moral effect can
perfectly well be mounted on railway carriages, but, as previously
pointed out, their utility as compared with bombing planes is a mooted
question. Indeed it may be questioned if such planes will not sup-
plant artillery even at shorter ranges.

70. The dispersion of the long-range gun firing on Paris at the
range of 110 Idlometers was such that 183 of the 303 shots fell inside
Paris (area about 90 square kilometers). The shell contained not
over 10 kilograms of explosive and the gun had a life of perhaps 50
rounds. Thus the gun could place during its life about 500 kilograms
of explosive somewhere within an area of 100 square kilometers.

71. The same results could be secured through the use of light
bombing planes operating at a height safe from anti aircraft guns in
daylight, and it is probable that dispersion would be considerably
less than that noted above (30 bombs were dropped on a single
railway shop in Paris) . Three light bombing planes could carry the
500 kilograms of explosive just noted and release it on a single
raid and even if all the planes were lost, which is not probable, the
cost of so delivering the explosive would be considerably less than if
it were delivered by the long range gun.

72. The dispersion of the United States 14-inch, 50-caliber gun at
the extreme range of about 40 kilometers is about 4 kilometers. It
fires a shell carrying about 40 kilograms of explosive and has a life of
perhaps 300 rounds. This gives a total of 12,000 kilograms of explo-

92

sive placed somewhere in an area of 16 square kilometers during the
life of the gun.

73. Twenty-five heavy bombing planes could drop this amount of
explosive in a single raid, and, even at night, ought to be able to put
it inside an area so large as 16 square kilometers.

74. On the other hand, there might be objectives at this range
which drop bombs could not destroy because of lack of penetrative
power. Further, for interdiction, it frequently is necessary to send
over some shells on very short notice and often at times when a plane
can not be used at all.

75. The conclusion of the writer is that at extreme ranges, that is,
70 to 120 kilometers, where the firing is for moral effect alone, this
service should not ordinarily be considered as a proper one for rail-
way artillery, the use of drop bombs being much more effective.

76. At shorter ranges, approximating 40 kilometers, many cases
woidd seem to exist in fire for destruction and interdiction where
drop bombs might be used to better advantage than railway artillery.
Some targets would probably be found, however, for which drop
bombs are ineffective, therefore railway artillery has a perfectly
proper field at these ranges. Further, artillery capable of these
ranges is required for accurate fire of destruction at shorter ranges,
hence it is available for the longer range work if required.

77. The experiences of the war seem to indicate that the field of
usefulness of railway artillery lies between the line on the diagram
for heavy artillery, marked 1918, and the line above, joining the
heaviest of the present railway guns. In other words, many of the
smaller of the present railway guns should not be considered in any
new program and there would seem to be little or no advantage in
trying to exceed the largest of the present guns. This confines the
field of railway artillery to calibers between 200 and 520 millimeters
(preferably 250 to 400 millimeters, since there is little need for a
caliber greater than 400 millimeters and the 200-millimeter gun can
probably be mounted on a caterpillar), and ranges between 10 and
40, or possibly 50 kilometers.

UTILITY IN COAST DEFENSE.

78. Railway artillery has been exploited chiefly in the past as a
means of coast defense. The outstanding advantage claimed for it
is great mobility, permitting concentration of a large number of guns
at any threatened point, and the effective defense of many places
which woidd not justify permanent works, as well as enabling the
guns to deliver their fire and retreat before effective counter-battery
fire from the sea can be commenced.

79. For this service the work would be primarily the same as that
demanded of the present coast-defense guns, i. e., the destruction of

93

1

battleships, destroyers, and lighter craft. This service calls for
extreme accuracy and rapid fire, in some for long-range direct fire,
and in others for medium-range plunging fire. These requirements
are quite similar to some of those for land warfare. The essential
dififerences, however, are that while in land warfare, the targets are
fixed, in coast defense they are moving, and provisions must be made
for following such a moving target; volley firing is often necessary.
80. Specifically the requirements of a mount for coast defense are:
(a) Wide traverse (60-180 degrees).
(6) Rapid fire,
(c) Quick emplacement.

((2) Sighting, elevating, and traversing mechanisms which can
be operated until the moment the gun is fired, and
simultaneously for all guns of a battery.

SECTION 3.

CHARACTERISTICS OF EXISTING TYPES OF RAILWAY

ARTILLERY.

81. Railway mounts have been constructed and used to our
certain knowledge by the French, British, Italian, German, and
American Governments. Information on mounts constructed by all
of these nations has been collected and tabulated for each type of
which anything could be learned. At the request of the technical
services of the French and British Governments all descriptions
and tabular data on their niounts are omitted from this volume,
which is intended for general distribution, and are placed in a separate
volume for confidential use only. The tabular data on American
and German mounts is given in section 10 of this volume. The de-
scriptions and tabular data of the French, British, and Italian
mounts are given in continuations of articles 3 and 10 in Voliune II.
All of the American and German mounts will be described in detail
in this voliune, each moimt being designated by the number it bears
in the table. In Volume II all other mounts will be mentioned, but
only those on which special information is available will be dealt
wiUi in detail.

82. The various designs described herein are criticized chiefly
under the head of "Difficulties involved in service." Most of the
mounts are criticized under this head on a basis of the type of firing
platform used and the time required for its installation.

83. There are in existence at the present time six types of mounts,
according to the characteristic design or natiu*e of their firing plat-
form. These are: (1) Mounts of the type of the American 8-inch,
plate 30, or French 200-millimeter, plate 10, using some simple type
of outrigger; (2) mounts of the shding and rolling type, similar to
the French 320-millimeter, plate 42, or the American 10-inch, plate
111, and the British 12 and 14-inch rolling mounts, plates 20 and 21,
or the American Navy 14-inch mount, plate 23, requiring a curved
track of very heavy construction to permit of traversing the mount
and to stand the exceedingly heavy service brought upon it in firing;
(3) semipermanent emplacement mounts of the type of the American

181768—21 7 (95)

96

12-inch BatignoIleSy plate 54, requiring a firing platform made up of
easily handled sections which are carried in a special platform car
provided with the necessary equipment for installing them; (4) semi-
permanent emplacement mounts of the type of the French 340-
millimeter gun moimt, plate 51, the 400-mQlimeter howitzer mount,
plate 52, and American 16-inch howitzer mount, plate 53, and Amer-
ican 14-inch naval mount, Mark I, plate 23, requiring an elaborate
subtrack platform of timber and steel construction which ordinarily
can not be installed in less than from two to five days and affords
only limited traverse of 10 degrees or less; (5) semipermanent
emplacement moimts of the type of the American 14-inch model E
moimt, plate 249, requiring a heavy base ring of comparatively
simple design, but which necessitates the use of a locomotive crane of
150 tons or more capacity; (6) semipermanent emplacement mounts
of the type of the German 21, 24, and 28-centimeter mounts, plate 24,
requiring a firing platform of structural steel, plate 55, which is
cumbersome to transport and requiring crane facilities for instal-
lation, or a reenforced concrete emplacement, plate 56, which requires
few facilities but considerable time for its installation.

84. So far, the use of the outriggers which are characteristic of
class 1, have been limited to guns of smaller caliber and, of course, in
criticizing the emplacements for larger guns, they are not being
compared with the outrigger scheme of emplacement of these smaller
mounts. In comparing the last five classes of mounts where one has
a choice of: (a) A new curved track of heavy construction, (6) a
special platform carried in a special car, (c) a heavy timber platform
requiring days for installation, (d) a simple steel base ring requiring
unusual facilities in the shape of a locomotive crane for installation,
or (e) a structural steel platform difiicult to transport and requiring
days for installation, or a substitute therefor, in the shape of a re-
enforced concrete platform, apparently any one type has a ques-
tionable advantage over another and the various designs described
in this section are not criticized on a basis of a preference for any of
the types so far mentioned. After careful examination and consider-
ation of all the types of railway mounts in existence, it seems possible
to combine in a mount for heavy guns, modifications of emplacement
schemes of the above types in such a way as to render the mount
almost universally serviceable. On plates 59 and 60 is a suggestion
for a design of a carriage for 10-inch, 50-caliber guns. Computation
of the necessary data indicates that this type of emplacement can
be installed almost as quicklj'^ and as easily as the simple outrigger
emplacement. It gives all round traverse if desired and will stand
the strains brought upon it by a 50-caliber, 10-inch gun.

97

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99

85. Going a step further, it seems entirely feasible to design a
mount which will embody the features of the sliding type mount in
the shape of steel shoes similar to those used on the 14-inch model E
mount and the features of the mounts of classes I and 6 in the shape of
a center pivot and traversing rollers attached to the car body to
secure the necessary traverse, and outriggers on the rear of the car
body to take a large part of the horizontal component of the force
of recoil. In addition, it seems possible to incorporate other features
of the 14-inch model E mount, in the shape of a simple base ring
which will be set on the concrete and on which the mount can be
operated for seacoast service. These simple base rings would be
inexpensive and could be installed in great numbers along our coast
at comparatively little cost. This type of mount would then service
perfectly as a coast defense moimt, and for land warfare could be
used as a combined sliding and rolling moimt with any desired
traverse, or as a simply and quickly emplaced mount requiring very
few extra facilities and having any desired traverse.

86. The writer has these two types in mind in criticizing the'various
moimts throughout this section, from the standpoint of time, and
difficulties involved, and facilities necessary in placing, removing,
and maintaining their platforms.

1.^4.7 HOWITZER ON RAILWAY MOUNT. (13)

87. This mount, which is model of 1917, was designed as an al-
ternate mounting for the pivot yoke and other rotating parts of the
4.7-howitzer pedestal mount, model 1915. The railway carriage
resembles very closely the design made up by Col. Peigne for the
155-millimeter French howitzer, ISdO. This can be seen by com-
parison of plates 62 and 65 with plate 4. Four of these mounts
were completed for service at Panama, and have functioned satis-
factorily.

88. Guns. — ^The gun that is used with this mount is a 4.7 howitzer,
model 1913. It is a wire-wound gun of 22.5 caliber length, plate 66,
and is provided with the standard American type interrupted thread
breechblock, which is fitted with a mechanical firing mechanism,
plate 67. The tube is rifled with 42 grooves, the twist of which is
to the right and at a pitch increasing from 1 turn in 40 calibers to
1 turn in 20 calibers. As mentioned before, this same model of gun
is used on the pedestal mounting, model 1915.

89. Recoil Mechanism. — ^The recoil mechanism is of the hydro-
spring type and as with the light field pieces, t^e entire recoil mech-
anism is combined in one cylinder, plate 68. It will be noted on
this plate that the hydraulic cylinder recoils with the gun while th^
piston remains stationary. The counterrecoil buffer is not a part

100

of the piston rod as in the usual railway design, but is attached to
the cylinder. The hydraulic cylinder head serves as a piston head
for the recuperator spring column. The length of recoil is 12 inches.

90. Elevating Mechanism. — It is possible to elevate the gun
from minus 10 degrees, the loading angle, to plus 40 degrees, by
means of the screw hinged to the bottom of the cradle at its forward
end, plate 69. This screw is driven by the bronze nut in the oscil-
lating central bearing. This bearing is supported on the cross shafts

as trunnions. Elevating handwheels are provided on both sides of
the carriage.

91. Traversing Mechanism. — ^The gun can be traversed through
360 degrees. The traversing mechanism comprises the handwheel
shaft and bevel gears shown on plate 70, with the worm shaft, worm
and bronze wormwheel shown on plate 69. The lower portion of
this bronze wormwheel serves as a drum for the two halves of the
friction band which are hinged on the stud bolt, passing through
the boss in the rear of the pedestal. The two halves of this friction
band are joined at the front by a bolt.

92. Top Carriage. — ^The top carriage comprises the cradle carry-
ing the hydrospring recoil mechanism and the pivot yoke with the
elevating and traversing mechanisms, plate 69. On this plate the
gun is shown on the pedestal for which it was originally designed.
On the railway mount the pedestal is part of the car body, but its
design, as well as the dimensions ot its machined surface are identical.
Any gun of this design with its pivot yoke can be transferred from
the separate pedestal to the railway mount. The weight of the gun,
cradle, and pivot yoke is carried on ball thrust bearings at the bottom
of the pedestal. The separate pedestal is provided with an azimuth
circle which is not provided on the pedestal of the railway mount.
Front and rear views of the top carriage are shown on plate 71, and
a right-hand side view on plate 72.

93. Railway Car Body. — ^The railway car body proper, plate 73,
comprises a central steel casting, of which the pedestal is an in-
tegral part, and the two structural steel ends riveted to this casting.
On each side of the car body two side arm castings are riveted, both
to the cast steel center section and the structural steel ends. On
each end of the car body are hinged three pieces of 0.5-inch armor,
the side pieces having two copper lined loop holes for machine guns,
and the end pieces one copper lined loop hole each. These plates of
armor can be let down to a horizontal position to serve as working
platforms. Two other plates which serve likewise as working plat-
forms are hinged to the central cast steel section of the car body.

94. Anchorage. — ^The mount is let down and clamped to the
track for firing. Additional provision is made for stabilizing the
mount when the gun is fired at any considerable angle to the direction

101

of the track. Side arms are attached to the car body on each side
by means of the side arm castings shown on plate 73. A jack screw
passes through the end of each of these side arms and cast steel foot
plates of simple design are provided on which the screws bear. These
foot plates are placed on well tamped earth, rock ballast or timber.
When firing at a wide angle to the track, it is necessary to put out
the side arms on both sides of the car, since the return of the gun to
battery has^a tendency to tip it in the direction of fire.

95. In the four corners of the central section of the car body there
are openings into which rail hook casings are fitted and bolted by
four bolts, plate 74. These casings, which may be taken out and
turned through 180 degrees, and replaced, are so designed that one
arrangement spaces the hooks for the 60-inch gauge track, and the
other for the 56.6-inch gauge. Inside of this casing there is a sleeve,
two parts of which project above the top of the casing and are fitted
with handles as shown on figure 3, plate 74. By means of these
handles the sleeves can be raised or lowered. A 0.875-inch pin
across the bottom of this sleeve, figure 3, passes between the rail
hooks and spreads them when the sleeve is raised, thereby freeing
the hooks from the rails. The two rail hooks are hinged to the
bottom of the clamping screw, which is operated by the two-handled
nut shown at the top *of the casing, figure 2. The sleeve and rail hooks
are carried normally at their highest position. When it is desired
to clamp the car body to the rails, the hooks are lowered as far as
they will go As they are lowered, the pin in the sleeve spreads
them and the lugs on the hooks strike the top of the rail when they
are in the proper position. The sleeve is then lowered by its handles,
and as it descends the opening pin permits the hooks to swing
together and close over the rail. The bottom of the sleeve encircles
the rail hooks and when in its lowest position binds them to the
rails. On the imder side of the center section of the car body there
are six pads which rest on the rails when the mount is lowered to the
firing position. These are of sufficient width to be adapted to the
60-inch or the 56.5-inch gauge. Each is provided with a pair of
rail stops, one on each side of the rail, which serve to prevent the
moimt from sliding across the rails and take the strain o£F the truck
pintles. One stop is longer than the other and they are inter-
changeable. For the 56.5-inch tracks the long stops are placed out-
side the rails and for the 60-inch tracks they are placed on the inside.

96. In the center of each of the structural steel ends of the car
body there is installed a screw lifting jack used in lowering the moimt
on to the track for firing and in raising it to the traveling position.
These jacks are shown in figures 1 and 3, plate 74. This lifting
jack comprises a cast-steel pintle guide rivetted into the car body,
a bronze pintle, a jack screw, bevel gears, spur gears, and two handles,

102

figure 1, plate 74. A roller thrust bearing is provided between the
top of the jack screw and the top of the pintle guide. The bottom
of the pintle rests on the center plate of the truck. Into the two
sides of the pintle are machined racks, which mesh with one of the
four pinions. The fourth pinion meshes with a rack in the side of
the moveable side bearing. As the pintle moves up or down, the
side bearing moves in the same direction at the same rate. The
first two railway moimts of this type manufactured were also equipped
with an alternate method of operating the jack screw. The upper
end of the jack screw was slotted and a capstan head provided to
fit into it. Four maneuvering levers were provided for the operation
of this capstan. The crank handles used to operate the lifting jack
.may be replaced by ratchet levers. The additional leverage obtained
through the use of these ratchets reduces considerably the eflFort
required for raising and lowering the car. When ratchet wrenches
are used with a lever arm of 32 inches, the force necessary on each
ratchet lever, one being used at a time on each end of the car, is 66
poimds to raise, and 50 pounds to lower. The time necessary to
raise the car, using ratchet wrenches, eight men working in reliefs
of four, is 5.5 minutes, and to lower ready to fire, approximately
5 minutes. When capstans are used the pull necessary at the end
of one lever to tinrn the capstan at one end of the car is 150 pounds
to raise and 100 pounds to lower. When four maneuvering levers
are used with one man at each lever, eight men in all, the car can
be lowered in 1 minute and raised in 1.25 minutes. When crank
handles are used the force necessary on eacji of the four handles is
85 pounds to raise the car, and 50 pounds to lower. The time
necessary to raise the car with crank handles, four men at each end
of the car, is 1.5 minutes, arid to lower, 2 minutes.

97. Armor. — ^Each end of the car is fitted with three shields of
0.5-inch armor plate hinged to the floor so that they can be swimg
down to a horizontal position, plate 73. When raised, the side
shields are locked to the end shield by angle iron clips and a locking
pin. The two pieces of angle iron are rivetted to the side shield
and straddle the end shield when vertical. A single pin locks a
side shield to the end. The outsides of the shields are fitted with
shield props which slide through guides on the car body. Collars
on these props limit the movement of the shields. The upper end
of the props extend through the shields and provide an attachment
for handle rods on the inside. Three of these handle rods can be
seen at the right end of the car, plate 73, the shield on the near side
in this case being cut away to show the opposite side. Men standing
on the car and clasping hands can let down the side shields by means
of these handles without undue difficulty.

103

98, Trucks. — ^The trucks are commercial four-wheel trucks of
50,000 pounds capacity. The brake mechanism has been modified
slightly to take a special brake bracket in order that the brake
handwheel might be located in the free space beside the lifting jack
toward the center of the car.

99. Ammunition Supply System. — ^No special provisions have been

made for supplying ammunition for this caliber of gun. All the

ammimition components are of such weight as to enable them to be

handled entirely by hand.

Plate 61

4.7 IN. Hownzeir iwmr MOUNT-noDEL t9i7

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2.— T-INCH GUN ON RAILWAY MOUNT. (14)

100. This combination of Navy gun on Army design of drop-
platform car was made up toward the end of the active period of
the war, in 1918. The railway cars, model 1918, were designed
for 6 and 8 inch seacoast guns, as will be explained later, being
modeled to a certain extent after the design already completed for
4.7-inch howitzers. Twelve of these cars were available, and since
they were equipped with hydraulic jacks over each of the trucks, it
was decided in 1918 to moimt Navy 7-inch guns on them for ser-
vice against submarines along our coast. A few especially designed
pieces of equipment were added as will be described later.

101. Guns. — ^The guns that are used on these mounts are 7-inch,
Mark II Navy guns, of 45 caliber length. They are provided with
an interrupted thread breechblock which is fitted with a mechanical
finng mechanism.

102. Recoil Mechanism. — ^The recoil mechanism is of the hydro-
spring type and comprises one hydraulic recoil cylinder attached to
the cradle, in the center of the bottom, and two spring recuperator
cylinders likewise attached to the bottom of the cradle, and on either
side of the hydraulic cylinder. The hydraulic recoil cylinder is
shown in detail on plate 78 and the general arrangement of cylinders
on the bottom of the cradle, on plate 79. The length of recoil is
21 inches. The spring columns, which are double, are divided by
spacing plates into five sections, plate 80.

103. Elevating Mechanism. — ^The elevating mechanism comprises
a rack attached to the left side of the cradle, plate 80, which is con-
nected with the handwheel through a pinion, shaft, slip friction
device, wormwheel, worm, bevel and miter gears, plates 81 and 82,
sections ZZ and YY. The gun can be elevated from minus 5 degrees
to. plus 15 degrees. The cradle trunnions are provided with a very
simple type of friction-reducing mechanism, as shown on plate 81.

104. Traversing Mechanism. — ^The gun can be traversed through
360 degrees. The traverse wormwheel is attached to the pedestal,
as shown on plate 77, and is connected with the handwheel on the
right side of the carriage through a worm, two sets of miter gears,
sections XX and W, plate 82. The pivot yoke is supported on the
pedestal by means of conical rollers, plate 83.

105. Gun Carriage. — ^The top or gun carriage comprises the cradle,
with recoil, elevating and traversing mechanisms, pivot yoke and
pedestal, plates 81, 79, 84, and 85: It will be observed on plates
76 and 77 that the original deck moimting of this gun is so low that
it was necessary to provide an additional cast steel base to elevate
the gun sufficiently to permit it to be fired at its maximum elevation
of 15 degrees when firing in the direction of the track. This cast
steel base has been bolted to the floor of the car and additional

118

cast steel brackets have been added to the side of the car to accomo-
date the additional width of the base over the width of the car.

106. Car Body. — ^At the begmning of this discussion it was
mentioned that this car body was originally designed for 6 and
8 inch seacoast guns. It was found impossible to use them because
the bottom outside angles in the well of the car extended beyond
the clearances permissible on European railways. Attention should
be called' to two other modifications that were made in the car body,
model 1918, Mark I. It will be observed on plate 769, that the out-
rigger struts are attached to the car body by means of cast steel
hinges, and from the bottom of the hinge to the end of the strut
there is a torsion rod for the purpose of counteracting certain
tendencies of the car to jump when gun is fired at low eleva-
tions. On the modified design, plate 88, one set of four struts is
attached to the car by means of ball joints. Four more struts are
attached in such a way as to swing only in one vertical plane, as
shown on plate 98. The car under discussion is likewise provided
with hydraulic jacks over the truck center plates and with adjusta-
ble side bearings, plate 86. The pumps for these jacks are installed
on the sides of the car, as shown on plate 76, and connect with the
inside of the hydraulic cylinder through the small hole in the piston.
Two racks meshing with pinions which in turn mesh with racks cut
in the side of the adjustable side bearings are machined into the
side of the cyUnder which also serves as a body center plate. As
the car is raised or lowered the side bearing clearance between truck
and body is held constant, due to the action of this compensating
device. In the modified design, these jacks and adjustable side
bearings were omitted and four jackscrews were placed at the four
comers of the lowest part of the flat car.

107. Anchorage. — ^The mount is emplaced for firing by first
injecting sufficient pressure in the hydraulic cyUnders to remove the
safety locking pins. It is then dropped to the rails by releasing the
pressure in the cylinders. No special emplacement is required.
The outriggers and floats are placed, as shown on plates 76 and 77,
for firing in any direction. It is necessary to put out four outrig-
gers since the car whips to such an extent as to loosen the outriggers
if only two are used.

108. Trucks. — ^The trucks used are of standard M. C. B. design
with cast steel side frames. They are provided with both hand and
air brakes.

109. Ammunition Supply System. — Projectiles are supplied direct-
ly from the ammunition car on to the ammunition table, shown on
the end of the car body in plate 77. On the side of this ammimition
table are two working platforms which are let down to a horizontal
position. The projectiles are transferred from the table into the gun

119

over the removable tray which can be seen on the top of the table
on plate 77. This ammunition table is light in design and is merely
bolted to the car; it can be transferred to the other end of the car
without diflBculty whenever desired. The ammunition cars used
with this mount are standard 8-inch ammunition cars.

110. Maintenance, Merits, Demerits. — It is believed that there
is no point in discussing the 7-inch moimt under these headings,
since they are purely emergency mounts and it is believed that they
do not represent a type that would receive consideration for future
construction.

Plate 75

LQAOATAUL

7IN. NAVr MOUNT-MARK I-MODEL 3

ON

RAILWAY CAR-MODCL I9I8MI

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131

3.— AMERICAN 8-INCH GUN ON RAILWAY MOUNT. MODEL 1918,

M. L (15)

111. This is a combination of seacoast defense gun and barbette
carriage on a special railway car. The mount is shown on plates
88 to 93.

112. Gun. — Seven different types of Army and Navy guns may
be used on this mount:

Army guns: Models of 1888, 1888 M.I., 1888 M.II. •

Navy guns: Marks I, II, III, IV, (16).
The Army guns are all 32 caliber in length; are equipped-with uniform
type of breech mechanism and are mounted on model 1918 barbette
carriages, having a standard type of cradle with hydraulic recoil
and spring return system. The Navy guns vary from 30 to 40
calibers in length, are equipped with four different types of breech
mechanism and are mounted in barbette carriages model 1918, M.I.
of the same general type as model 1918.

113. Recoil Mechanism. — The recoil mechanism as noted above
is of the hydro-spring type with one recoil and four spring cylinders
arranged symmetrically about the outside of the cradle. Details of
this mechanism are shown on plate 94.

114. Elevating Mechanism. — Elevation from zero to 42 degrees
is secxu'ed through a segmental circular rack attached to the bottom
of the cradle. A Hindley worm meshes with this rack. Three sets
of bevel gears on as many shafts lead to the handwheel, plate 94.
Any thrust due to fire is taken by the worm and transmitted from
it to the side frames through the heavy transom casting in which
it is mounted. One turn of the handwheel moves th^ gun through
approximately 0.333 degrees in elevation. Details of this mechanism
are shown on plate 93.

115. Traversing Mechanism. — The traversing mechanism pro-
vides for a total movement of 360 degrees. The gun and cradle are
carried in side frames on a racer casting which is supported by
conical traversing roUers. A complete circular rack is mounted on
the base ring into which meshes a pinion of the traversing mechanism
mounted upon the racer. This pinion connects, through a slip-
friction device, a wormwheel and worm and two bevel gears, with
the handwheel. The slip friction serves to relieve the gearing from
any imdue strain from pressure of projectile against lands of the
gun in firing. An azimuth circle with pointer is provided for reading
changes in azimuth. One turn of the handwheel moves the gun
through a little more than 1 degree in azimuth. Details of this
mechanism are shown on plate 94.

116. Gun Carriage. — The gun carriage, plate 33, includes the
cradle, carrying the recoil and spring cylinders, the elevating and
traversing mechanisms, described above, and the cast-steel side

132

frames, racer and base ring to which these mechanisms are assembled.
An operating platform of structural steel is attached to the rear of
the side frames and rotates with the gim in azimuth.

117. Railway Car Body. — The railway car body is of structural
steel, drop center type construction, with the barbette carriage moun-
ted in the well, plate 92. The body is provided with jack transoms
at each end of the well, which mount the four screw jacks used for
liftinggthe body, carriage, and gun for emplacing. French couplers,
buffers, etc., were originally provided for service in France, but have
since been replaced by the standard M. C. B. type. All of this is
shown in detail in plate 92. Air-brake equipment is likewise sup-
plied. French, English, and German railway mounts are not pro-
vided with air brakes.

118. Anchorage. — ^For firing, the car body, carriage, and gun
rest upon a firing platform which takes the vertical component of
the shock of fire, while the horizontal component is taken by out-
riggers, plates 88, 89, 30, 95, and 96. The firing platform consists of
two lines of H -beams placed under the car, along the railroad
ties outside the rails, and of six wooden crossties. The car body. is
raised by means of the jacks; crossties 'are then put in place across
the top of the H -beams and under the car body and the car is lowered
upon them. The outriggers consist of wooden floats about 5 feet
square, cast-steel float plates resting against these and serving as
sockets for the ball ends of the struts, and struts made of pipe and
extending from these plates to suitable attachments on the car body.
These attachments are located, fom* on each side of the car, in such
a way that the car can be braced in all directions. The eight floats
are placed in as many holes dug in the adjacent ground and the struts
are tightened up between them and the car. These floats are located
as shown to brace the car horizontally in every direction ; details of
this arrangement are shown in plate 30. A speed test by a trained
crew showed that the car could be emplaced and prepared for firing
in 45 minutes and that the emplacement could be taken up and all
material loaded on the car in 25 minutes.

1 19. Trucks. — The trucks are standard 70-ton M. C. B. type having
6 by 11 inch journals and crown cast-«teel side frames. The wheels
are 33 inches in diameter and are of rolled steel. Both hand and air
brakes are provided. Details are ^hown in plate 97.

120. In addition to the above trucks, a complete set of equipment
is furnished for hauling this material over 60-centimeter gauge
track. This equipment consists of a gun transport car, plate 98,
with loading and unloading rig, a pair of 12-wheel trucks which are
substituted for the 70-ton M. C. B. trucks and carry the car body
and gun carriage, and narrow gauge shell cars for the ammunition,

133

plates 99 to 105. Powder, spare parts, tools, etc., are carried on
narrow-gauge flat cars.

121. Ammunition Supply System. — A standard-gauge, steel box
car with special racks for holding ammunition is provided. This is
shown on plate 106. The car has an I-beam trolley, the track of
which can be pushed out beyond the end of the car when desired.
The ammunition car is located directly back of the gun car, am-
munition is rim out on its trolley and is dropped on to a loading
box located on the after end of the gun car. From there, it is picked
up by a small jib crane located on the rear end of the gun operating
platform, transferred directly to a second jib crane and by means
of the latter swung to the breech of the gun. This method of oper-
ation can be employed for angles of fire of 35 degrees or less on
either side of the center line of the car. Beyond that, it is necessary
to transfer the ammunition to the ground at one side of the car so
that it can be picked up by the jib crane. The entire operation of
this arrangement is well illustrated on plate 108.

122. Maintenance. — Neither carriage nor car involve any new
or uncertain features which might be expected to require extraor-
dinary maintenance. It is perhaps to be anticipated that the car
body may, after repeated use in trains, develop a permanent set or
sag which would be large enough to necessitate correction. Inas-
much, however, as the mount would probably not be subjected to
service either as continuous or as severe as the standard flat car, it
is not felt that this should introduce a serious difficulty.

123. Difficulties Involved in Service. — Several minor criti-
cisms in regard to the operation of this mount have developed in
connection with experiments made upon it in the United States.
Some of these criticisms no longer apply to the mount as it exists
now, the design having been modified to correct them, and they are
mentionc'd only to point out what difficulties might have occurred
from previously used designs, and to show the development that
has taken place.

124. When the car is first fired, the floats jneld more or less ac-
cording to the nature of the ground, and it is necessary to tighten
them up or repack the earth behind them. This should not be a
serious matter when a large number of shots are fired from the same
emplacement in approximately the same direction.

125. The elevating mechanism, before the addition of the anti-
friction device, was comparatively slow in operation. Somewhat
over a minute was required to move the gun through the full arc in
elevation or depression, even under the best conditions. This no
longer applies, since the antifriction mechanisms have so much
reduced the effort required to elevate and depress the gun as to

134

permit of the use of a gear ratio approximately three times as great
as the original.

126. A by-pass pipe is provided from the rear end of the recoil
cylinder to the forward end of the recoil buflFer. A check valve in
this pipe is exposed to severe and sudden pressures on the counter-
recoil, and on one occasion during proof it failed to function properly.
On investigation, it appeared that this failure to function was due to
unsatisfactory machine work, and on paying more attention to the
fine machine work of these valves no such difficulty has been ex-
perienced on any other mounts.

127. It is difficult to swing the shell away from the breech when
carrying it to loading position on the second jib crane. The ope-
ration is entirely possible, however.

128. The speed-test of this mount made by a trained Coast Artillery
crew gave a record of four shots in 10 minutes. This is rather slow
for the caliber. Since this time, an improved elevating mechanism
has been installed, so that it is felt that this record could be bettered.

129. Merits. — The one feature which makes this mount con-
spicuous among railway carriages of all armies and which likely
would have made it of very great value in the present war is its
system of anchorage. There is no other mount in any of the allied
armies which has an anchorage system that compares with this in
effectiveness, nor which can be prepared for action in so short a
time. The system is self-contained, if this term may be used to
state the fact that the anchorage system is a traveling part of the
carriage and it is of such a type as to permit the gun to be fired
without any difficulty in any direction. To realize the full effective-
ness-of the efficiency of this anchorage system it shoiJd be compared
with the anchorage used with the several types of 9.2-inch British
guns on railway mounts, the 19 and 24-G French howitzers on im-
provised all-round traverse platforms, and the 240-millimeter French
gun on the railway carriage known as the Colonies type, plate 27.

130. Demerits. — The characteristics of the carriage which appear
to those who have observed the operation of allied railway artillery
as demerits, are as foUows: The elevating system includes a rack
bolted to the bottom of the carriage meshing with a Hindley worm.
It seems certain that under the working conditions that prevailed
in the present war considerable difficulty would have been experi-
enced in maintaining this rack and worm in proper working order.
Second, a worm of the type of the Hindley worm can not easily be
secured in the field, and inasmuch as such a worm must be worn in
with the rack, it is possible that some difficulty might have been
experienced in the maintenance.

135

131. A second point which applies perhaps entirely to the mount
as or^nally designed is the lack of rigidity of the underframe. The
whip of the car body was so great as to make it impossible for the
personnel to remain upon it when the gun was fired. The car body
as at present designed, however, has proved satisfactorily sturdy
and rigid, and it is probable that there is not sufficient vibration
either to injure the barbette carriage, even after long service, or to
injure the personnel if they desire to remain on the mount while it
is in action.

Plate 87

eiN.aWBtTTE CARRIAGC-MOOEL rate

S-INCH AMERICAN GUN ON RAILWAY MOUNT.

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4.— AMERICAN 10-INCH GUN ON SLIDING RAILWAY MOUNT.(17)

132. These guns are mounted on what are termed ^^ sliding mounts ''
in the American and English Armies, and ^'glissement mounts" in
the French Army. The gun is swung directly by means of its trun-
nions, in bearings mounted rigidly on the side girders of the car body,
and the gim and moimt slide back together along the track in recoil.
The mount is stopped by the friction between the special jacking
beams or sleepers in the bottom of the mount and spBcial firing
beams or I-beam stringers attached to the ties of the track. Most
moimts of this type have no internal means of traversing the gun
with respect to the car body or the trucks, and they must be operated
on curved tracks to train the gim in azimuth. This is the first
modem mount of this type to be described and it may be of interest
to mention some points with reference to its development. It will
be recalled that in the ^'Historical introduction, " mention was made
of the 13-inch mortar mount constructed and operated by the Union
Army, in which case the gun carriage slid on rails on top of the car
and the car rolled back on the track when the gun was fired.

During the interval between the Civil War and the present war,
several proof moimts were constructed by various countries, operating
on the same principles, but at the beginning of the present war no
nation had constructed for itself any railway moimts on which
provision had been made for dissipating the energy of recoil by means
of friction between special mechanisms designed as a part of and
constructed into the car body and the railway track. The only
railway mounts that the French Government possessed at the be-
ginning of the war were some 200-millimeter mounts which the
Schneider Ordnance Co., had constructed for the Peruvian Govern-
ment and which had not been delivered. The designers of the various
French ordnance companies were hard put to design carriages on
which their heaviest seacoast guns could be mounted and which
could be constructed with the facilities available in a satisfactorily
short period of time. The scheme of mounting the gun rigidly in
the carriage and permitting the mount to slide back on the track in
recoil was developed by the Schneider Ordnance Co., late in 1914,
and the first carriage mounting a 320-millimeter gun was proved at
their heavy artillery camp in February or March, 1915. The de-
signers had considerable misgivings with reference to the performance
of this carriage, which had not been developed through any slow
process of evolution; but the exhaustive test to which this first
carriage was subjected soon proved that although it might appear to
be a crude mechanism it nevertheless was unusually sturdy and the
gun could be operated as rapidly and as accurately as any other gun

157

provided with the most elaborate of recoil mechanisms and accessory
equipment. The French Government then proceeded to momit as
rapidly as possible a great number of their large guns on carriages
of this type.

133. It is very significant that none of the nations engaged in the
present war used any great number of large guns, if any at all, that
were finished after their entrance into the war. The writer knows
of only two guns finished and mounted by any of our allies, on railway
carriages, since 1914. All other guns mounted were either in storage,
or were removed from battleships or coast fortifications. On the
entrance of America into the war, it was discovered that the supply
of guns of some of our allies was running dangerously low and it was
proposed that we supply them with some of our heavy guns. Fifteen
of the 10-inch guns of ^ the model that are being mounted on these
carriages, were sent to France in September or October of 1917, to
serve as a reserve and at about the same time, it was decided to have
the French Government construct 36 new mounts for more 10-inch
guns which would be sent across. Shortly thereafter, the French
Government found that its manufacturing facilities would not permit
it to supply all of the material for these mounts, as well as to construct
them, and plans were made to have the plates, castings and foldings
supplied, cut to shape and rough machined in America, and assembled
in France in the shops that had been constructing the 320-millimeter
sliding mounts.

134. The first four sets of these parts arrived in France several
months before the signing of the armistice and were in process of
fabrication at . the time of the signing of the armistice. It was
planned to have most of the mounts finished and ready for service
for the big offensive that was planned for the spring of 1919. Several
months after the armistice was signed, the four sets of parts that had
arrived in France were shipped back and plans were made for com-
pleting the mounts in America. Many of the details of design have
since been changed and it is probable that only a limited number of
the mounts will be constructed. In considering this type of mount
from many standpoints, it should be understood that it was origi-
nally designed under the stress of the most desperate need and was
not chosen because it was the finest possible carriage on which the
guns could be mounted. It proved most conmiendably sturdy and
served its purpose well in the type of warfare for which it was de-
signed. General views of the design that will be described are
shown on plates 109, 110, and 111.

135. Gun. — ^The guns to be used with this mount are the 10-inch
models of 1888, 1888 M. I., 1888 M. II. and 1895, all of 34 caliber

158

length, and eight different models of Navy guns from 30 to 34 caliber
'ength. All of these guns are provided with fixed trunnions. All of
the Army guns are provided with interrupted thread breech blocks
and the Navy guns with stepped thread blocks. All of the breech
blocks are fitted with mechanical firing mechanisms. All of the
Army guns are rifled with 60 grooves and the twist of the rifling is to
the right, progressing in pitch from 1 turn in 50 calibers to 1 turn in
25 calibers.

136. Recoil Mechanism. — No recoil mechanism in the ordinary
sense of the term, is provided with this type of mount. The gun is
fixed to the girders as already noted, and the entire mount slides
back along the track as a unit under the shock of recoil. A description
of the mechanisms employed to bring the mount to rest, is given
under the head of ' 'Anchorage.'* Counter-recoil is accomplished by
the same mechanism that is used in traversing the mount. The
length of recoil averages 1 meter.

137. Elevating Mechanism. — Provision is made for elevating the
gun from minus 7 degrees, the loading angle, to plus 54 degrees.
This provision of so great an elevation, that prior to 1917 would
have been considered entirely unwarranted, has come about through
our experiences in this. war. No one is now certain of what con-
stitutes a proper line of demarkation between a gun and howitzer,
and no one can be certain either that within a comparatively short
time we may not find it profitable to operate all guns, as well as
howitzers, at these extreme elevations. The elevating rack is bolted
to the right side of the gun, plates 110 and 111. The pinion meshing
with the rack is connected with the handwheels provided on both sides
of the carriage through a slip-friction device, plate 113, a worm-
wheel, worm and bevel gears. One revolution of the handwheel
moves the gun through 1.37 degrees in elevation. To reduce the
effort required in elevating and depressing the gun, anti friction
devices have been provided on each trunnion. The design of these
devices is shown on plate 114. This is a design of antifriction
device, that to some extent has been taken from French railway
mounts, but has been modified and improved. It has been used
already on several other railway mounts and has proved particularly
efficient.

138. Traversing Mechanism. — Since the gun is mounted rigidly
in the car body and it is not possible to move the car body with respect
to the trucks, it is necessary to move the entire mount along a curved
track to train the gun in azimuth. The procedure in preparing
these curved tracks has been described in other portions of the re-
port. The mechanism used in moving the mount along the track is

159

tenned a translating mechanism and is incorporated in the front
truck. Gear cases and two handles axe constructed on both sides of
the front truck as shown on plate 109. Sprocket wheels on the
cross driving shaft of this mechanism are connected with sprockets
on two axles, as shown on plate 117. A clutch is provided by which
the mechanism can be thrown out of gear for firing, and for traveling
it is necessary to remove the chains. It is possible for four men to
move the mount along the track by means of this mechanism at the
rate of about a meter per minute. The ratio is 117 turns of the
handle for one revolution of the car axle.

139. Gun Carriage. — ^The gun carriage is incorporated in the car
body and will be described in the next paragraph.

140. Car Body. — ^The car body is made up of two structural
steel box girders connected by deck plates and a series of structural
steel transoms. The jack screws required for the operation of the
jacking beams, the elevating mechanism and the loading mechanism
are all incorporated in this structural steel body. The success of
this type depends upon the car body being given a rigidity approxi-
mating as closely as possible that of a steel casting. As a con-
sequence, it is necessary to have the web plates of all the transoms
come into contact with the web plates of the side girders and to have
the seats for all of the fittings carefully and accurately machined.
The rivetting must likewise be well nigh perfect.

141. Anchorage. — The only anchorage with which this mount is
provided, is the friction between the sliding beams and the I-beam
stringers or firing beams attached to the ties. The I-beam stringers
are placed on the firing track or epis, as shown on plate 118. When
the gun has been properly trained in azimuth by moving the mount
along the track by means of the translating mechanism already
described, the six sleepers shown in their relative position on plate
109, and in detail on plate 119, are forced down on these firing beams
as hard as a man on each of the ratchet levers is able to force them.
The design of the jackscrew and operating mechanism is shown on
plate 117. The men operating these jacks run the sleepers down by
means of the handles, first giving the handles one full turn at a time
at the call of a sergeant, until the sleepers come into. contact with
the beams. Then they turn the handles through half revolutions in
concert, as long as they are able to turn them. The final tightening
is done by means of the ratchet levers and is likewise performed in
concert at the call of the sergeant in charge. These jacks normally
take about one-half of the entire dead load of the mount and practi-
cally all of the firing load. When the gun is fired the entire mount
slides back on the stringers, an average distance of one meter. The

181768—21 — -11

160

jacks are then released, all of the men working in concert as in
tightening, and the mount is returned to its firing position by the
translating mechanism. In the various actions by this type of artil-
lery that the writer has observed, no cases were seen in which the
rate of firing was limited by the time required to return the mount
to its firing position and place the jacks. The time required for load-
ing the gim was always the determining factor in the rate of firing.

142. Trucks. — ^These moimts are provided with two special 6-axle
trucks with 5.5 by 10 inch journals and 36-inch wheels. The truck
frames are of structural steel and the axles are equalized in groups of
three. The design of these trucks is shown on plates 120 and 121.
Spring-supportbd conical rollers of a design shown on plate 122 are
provided between the trucks and the car body to serve as side
bearings.

143. Ammunition Supply System. — ^The ammunition car that is
to be used with this mount is identical with that provided for the
8-inch railway mount, but with modifications in the fixtures to take
the 10-inch ammunition. This car is shown on plate 123. With
French mounts it was customary to transfer the ammunition from
the ammunition car to the moimt by means of a shuttle car known
as a transbordeur. No shuttle car is provided with this 10-inch
moimt; instead, a track is provided on the rear truck with an extension
made up of two hinged wings, plate 125, which carries a shot truck
onto which the projectile may be laid from the trolley of the am-
mimition car. Provision is made on the truck just back of the mount,
plate 124, for storing four projectiles, two on either side of the track.
Two identical jib cranes are provided on the rear of the mount,
plate 124, and of a design shown on plates 125 and 126, by means of
which projectiles may be picked up from the rear or from the side
and placed on the tray of the loading stand. This loading stand is
of an entirely new design and is collapsible for traveling. The details
of its design are shown on plates 127 and 128. The loading angle is
minus 7 degrees and when the projectile is given a start down the
greased tray it acquires sufficient velocity to ram itself. In the top
view, plate 124, there are four doors in the deck of the mount, be-
tween the two crane pedestals. These are doors to four asbestos-
lined powder-storage boxes in which sixteen charges of powder can
be stored with little probability of change in temperature within a
reasonable time or danger of ignition from fire.

144. Maintenance.— The French and American personnel oper-
ating these mounts in the field, found them most satisfactory from
the standpoint of service. The mounts were exceedingly sturdy and
there are few mechanisms requiring much attention. The oiling of

161

the jacks, truck bearings, trunnion bearings, breech mechanism, etc.,
is about the only maintenance that this type requires.

145. Difficulties Involved in Service. — ^The one difficulty that
may be laid to this mount in service is the time required for the laying
of a new firing track and occasionally the difficulty in finding satis-
factory positions for these firing tracks. The time required for the
laying of such a track averages from two to three days. The position
must be rather well prepared and the track, composed of heavy rails
and ties, must be laid on a heavy bed of good ballast. It is necessary
to level and tamp the track perfectly. It is well nigh impossible to
conceal a curved firing track from the air photographers and the only
recourse that the French had was to construct so many curved firing
tracks over the front that whenever they desired to commence an
action the firing tracks were already in place and the air photographs
taken by the enemy did not show any new tracks. It is not impos-
sible to conceal a mount on the track.

146. Merits. — The merits of this mount are its sturdiness, its
small maintenance and the speed with which it can be placed on a
firing position and removed.

147. Demerits. — ^The demerit is that it requires a firing track
which can not be laid under two days and which can not be concealed
from the air photographer. As noted before, it is frequently dif-
ficult likewise, to find suitable positions for these firing tracks and
under such circumstances an unusual amount of time may be re-
quired for its installation. It can not be laid on filled ground and, of
course, time is ordinarily not available for excavating a cut if this
should seem necessary in a desirable position. From the standpoint
of its use at the present time a very serious demerit is that it is
exceedingly difficult to use it against a moving target. It probably
can be operated on a turntable of exceedingly heavy construction.
In this case the sighting apparatus will have to be constructed as a
part of the turntable, since the mount must be trained in azimuth
until the instant of firing. It will not be impossible to construct a
turntable of such strength to permit the mount to slide on it in
firing. No trials have ever been made to determine whether the
mount is sturdy enough to take the shock of recoil in the event that
it is held rigidly to a foundation.

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5.— AMERICAN 12-lNCH MORTAR ON RAILWAY MOUNT.(18)

148. This mount is of the cradle recoil top carriage traverse type
and is •similar in design to the mount for the 8-inch gun. The recofl
mechanism is hydropneumatic while that of the 8-inch mount is
hydrospring. It is illustrated on plates 130 to 138.

149. Gun. — ^The piece used with this mount is the 12-inch coast-
defense mortar, model 1890, Mark I, of 10-caliber length. It is
provided with an interrupted thread breechblock which is fitted
with a mechanical firing mechanism. There are 72 grooves, and the
twist of the rifling is to the right, the pitch progressing from one
turn in 40 calibers to one turn in 20 calibers.

150. Recoil Mechanism.^ — The recoil mechanism is of the hydro-
pneumatic type. Two hydraulic cylinders are mounted on the bottom
of the cradle and one pneumatic recuperator cylinder on the top.
There is nothing unusual in the design of the hydraulic recoil cylinders.
This is the first mount described on which a pneumatic recuperator
is used, and it wiU perhaps be well to describe the recuperator mechan-
ism in detail. It is shown in section on plate 38, and is in general
typical of the design of the pneumatic recuperator used on the 12-
inch Batignolles mount and the 12-inch 20-caliber howitzer. This
recuperator is composed of three main parts, a cylinder which is
attached to the cradle, and whose rear end, plate 38, serves as an
air reservoir, a hollow piston attached to the gun, and a floating
piston, the rod of which can be seen passing through the hollow
piston, and the head of which fits in the air cylinder.

151. On plate 134 it can be seen that the cross head on the front
end of the hollow recuperator piston is attached by means of two
long tension rods to the recoil lug on the rear of the gun. The space
in the recuperator to the rear of the floating piston, plate 38, is
filled with air at a fixed initial pressure. The floating piston is
fitted with a series of U-shaped leathers, which serve in part to retain
the air pressure. The space between the floating piston and the hol-
low piston is filled with a heavy oil or light grease. It can thus be
seen that if there is ahy leakage in this cylinder it is a leakage of
the oil which fills the space between the floating and hollow piston,
since the air can not escape except by passing both the floating
piston and the oil piston. When the gun recoils, the tension rods
shown on plate 134 pull the hollow piston back, and the pressiu-e
transmitted through the oil or grease forces the floating piston to
the rear at the same time. The length of recoil is 30 inches and the
position of the floating piston at maximum recoil is shown by dotted
4ines. As soon as the gun has ceased to recoil the air pressure
behind the floating piston forces it forward and in turn pressxire is

184 '

transmitted through the oil and forces the hollow piston and the gun
forward.

1 52. The front end of the rod of the floating piston proj ects through
the hollow piston and beyond the end of the bracket, which is attached
to the gun sleigh. As oil leaks out of the hollow piston the floating
piston moves forward under the air pressiu*e. The forward end of the
floating piston rod is graduated and when certain of these graduations
appear it is an indication that the oil supply must be replenished.
As additional oil is forced in the floating piston moves to the rear,
again building up the air pressure. The oil pump used in this oper-
ation can be seen mounted on the cradle beside the recuperator
cylinder. A supply of oil is carried in the pump casing and the pump
is operated by means of the long lever shown in the space between
the hollow and floating pistons. On plate 134 an air bottle can be
seen on the working platform of the mount. This bottle is connected
by a small pipe with the rear end of the recuperator cylinder and
supplies it with air to increase the pressure whenever necessary.

153. The cradle is noticeably of a clumsy design. The mortai-s
used on these mounts were originally mounted in their seacoast
carriage by means of trunnions attached to the gun. To get the
required amount of bearing surface for a recoil of desirable lengtli, it
was necessary to mount the gun in what is termed a sleigh. This
sleigh is composed of two rings and two runners or splines, plates
38 and 134, The forward ring fits over the tapered muzzle of the
gun and the rear ring over the breech. They are connected by two
runners which fit over the original trunnions of the gun, thereby
attaching the entire sleigh rigidly to the gun. This sleigh is in turn
mounted in the cradle, which is necessarily very wide to accommodate
the large sleigh runners. The cradle is supported in the side frames
of the top carriage by its own trunnions.

154. Elevating Mechanism. — Elevation from minus 5 degrees to
plus 65 degrees is secured through a segmental circular rack attached
to the bottom of the cradle; a pinion meshing with this, a slip-
friction device, wormwheel and worm, and a set of bevel gears
leading to the handwheel. Any excessive thrust due to fire causes
slipping in the friction device and can not impose excessive strain on
the gears. One turn of the handwheel moves the mortar through
1.004 degrees in elevation. Details of this mechanism are shown
on plate 38.

155. Traversing Mechanism.— The traversing mechanism pro-
vides for a total movement of 360 degrees, as with the 8-inch carriage.
Gun and carriage are carried in cast steel side frames on a racer
casting which is supported by conical traversing rollers, plate 135.
A complete circular rack is mounted on the base ring; a pinion of

185

the traversing mechanism which is mounted on the racer meshes
with this rack. This pinion connects through a vertical shaft, worm,
and wormwheel with the operating handwheel. Any strain from the
pressure of the projectile against the lands of the gun in firing is
taken up as thrjist on the worm. An azimuth circle with a pointer
is provided for reading changes in azimuth. One turn of the hand-
wheel moves the mortar through 0.837 degrees in azimuth.

156. Gun Carriagh. — The mortar carriage, plates 38 and 134, is
similar in general design to the 8-inch barbette carriage, model of
1918. Certain radical diflFerences have been made in the details, of
course. In this carriage the pneumatic recuperator has been sub-
stituted for the spring recuperator used in the 8-inch gun. The
elevating mechanism comprises a segmental spur-gear rack and a
pinion, while the 8-inch mount was provided with a Hindley worm
and segmental worm-gear rack. The base ring of the 8-inch mount
was provided with a pintle at its center, while in this case the pintle
is part of the racer and is of very large diameter, plate 38. On the
8-inch mount the traversing rack is attached to the base ring inside
the roller track. On the 12-inch mortar moimt the traversing rack
is attached to the outside of the roller track. On the rear of the
working platform of this mount an ammunition table is provided,
since the projectiles are of such weight and size that they can not be
handled by the simple method used on the 8-inch mount.

157. Railway Car Body. — ^The railway car body for a number of
these mortars is identical with that of the railw^av car model 1918,
Mark I, plate 133, for the 8-inch gun. The mortar carriage proved
sufficiently heavy to cause a deflection of about an inch in the center
of the 8-inch design of car body, hence a modified design was made
in which the depth of the web plates was increased, especially in the
inclined portions of the car body. Four-fifths of the total number
of mortar car bodies are of this latter design.

158. Anchorage. — The scheme employed in anchoring this mount
is shown on plates 130, 131, and 136. It is identical with that used
with the 8-inch mount.

159. Trucks. — ^The trucks on this car differ from those used with
the 8-inch mount due to the heavier load carried. Thev are 6-wheel
type with 5.5 by 10 inch journals and 28-inch wheels. Both hand
and air brakes are provided. Details are shown on plate 137. A
set of equipment for transporting the mount over narrow-gauge
track is .provided and is in every way similar to that furnished with
the 8-inch mount, plates 99-105.

160. Ammunition Supply System. — The ammunition car is the
same as that provided for the 8-inch mount, plate 106. It is located

186

diree^ly back of the gun car in firing so that the ammunition can be
let down directly on the truck mounted on the special track built on
the car body. From this truck it is picked up by a jib crane on the
rear of the mortar-operating platform and is swung around and
lowered to a loading stand on the back of the latter. From here it
is sUd into the mortar along a loading tray which can be put in place
temporarily between tiiis lo.ading stand and the mortar breech.
The loading angle is minus 5 degrees. This arrangement is illustrated
in detail in plate 138.

161. Maintenance. — ^The only especially novel feature in this
mount, so far as American practice is concerned, is the pneumatic
recuperator. Early in proof tests the valves on the pump for re-
charging the recuperator stuck on one occasion. This difficulty was
easily remedied and the recuperator has since operated perfectly. No
further difficulty should be experienced in the maintenance of this
mechanism. The mortar and carriage are somewhat heavier than
the 8-inch gun and carriage and cause a very marked deflection in
the 8-inch design of car body used with 17 of these mortars. There
is a possibility of the development of a permanent set or sag in these.

162. Difficulties Involved in Service. — ^Proof of this mount
indicates that it operates satisfactorily in evfery respect at elevations
between 35 degrees and 65 degrees. At lower elevations some dif-
ficulty has been experienced mth the settling of outrigger floats in
the ground and particularly wdth jumping of the car. It appears
that at elevations below 25 degrees the mount is dangerously unstable.

163. The heavy deflection of the 8-inch design of car body may
cause considerable difficulty in emplacing, as the car must be raised
by auxiliary jacks before the standard jacking beams can be inserted.
This operates merely to increase the time required fbr emplacing and
removing the mounts and it should not constitute a serious difficulty.

164. Merits. — One of the merits of this carriage is its system of
anchorage, which is identical with that of the 8-inch railway carriage.
Attention should also be called to the cradle, which is of excellent
design; it is felt that it will give excellent service.

165. Demerits. — Some difficulty may be experienced in using a
few of these mounts in the field, inasmuch as the deflection of the
underframe is so great as to make it impossible to use the jacks pro-
vided for lifting the car in order that the firing beams and sleepers
may be placed to form the firing platform. It may be necessary to
use auxiliary jacks.

i ;
i i

196

197

6.— AMERICAN 12-INCH GUNS ON BATIGNOLLES TYPE OF RAILWAY

MOUNT. (19)

166. This mount is built on a design almost identical with the
design of the mounts on which the French have placed 305 and 340
millimeter guns and 370-millimeter howitzers. Modifications were
made in the French design to adapt the mount to American manu-
facture and the American guns. This type of mount, plates 26, 140,
and 141 is a development of this war. It was designed by the Society
des Batignolles in France, during the latter part of 1914, and the
first mount was tested at the Railway Artillery Camp in January or
February of 1915. All mounts of this type rendered most excellent
service throughout the war, proving definitely the merit of the design.
The original American plan was to mount a number of 10-inch
34-caliber guns, models of 1888, 1888 Mark I and 1888 Mark II, on
the same design of carriage. This has not and likely will not be done.
It can be done at any time without great difficulty simply by pro-
viding a new cradle with decreased inside diameter and a slight
modification of the throttling grooves and the recoil cylinders.

167. Guns. — ^The guns that are being used with these moimts are
12-inch, models of 1895 and 1895 Mark I, all of 35-caliber length.
These guns are provided with the interrupted thread type of breech
block which is fitted with a mechanical firing mechanism. The guns
are provided with heavy splines on top and bottom, which not only
prevent rotation of the gun on firing, but likewise carry the entire
weight of the gun in the cradle ; that is, the gim does not touch the
cradle except in the spline ways. This is not considered good design,
but the French practice was followed in preference to making any
radical modifications in their design at a time when it was imperative
that the guns be mounted with the least possible delay. Difficulties
already experienced in proof firing indicate that unusually fine ma-
chine work is required on the splines and spline ways to prevent
excessive friction and sticking of the gun before it has returned en-
tirely to battery. The inside construction of the cradle with the
spline ways into which the splines fit is shown on plates 142, 143
and 144.

168. Recoil Mechanism. — The recoil system is hydropneumatic
and comprise two hydraulic recoil cylinders attached to the bottom
of the cradle, and one pneumatic recuperator attached to the top,
plates 37, 142, 143, and 144. The length of recoil is about 900 milli-
meters and no pit is required under the mount for firing at the highest
elevation. The air required for the charging of the pneumatic recu-
perator is furnished in bottles. In field service extra bottles are ordi-
narily carried on the mount. The design of the pneumatic recoil is

. 198

essentially the saine as that on the 12-inch mortar which has already
been described in detail.

169. Ei-EVATiNO Mechanism. — ^It is possible to elevate the 12-inch
gun from minus 5 degrees to plus 36 degrees. The elevating mecha-
nism is in duplicate with a rack attached to each side of the cradle and
pinions connecting through slip friction devices, worm and worm-
wheels, spur gears, a shaft, miter gears, and chains to the hand-
wheels. This mechanism is shown in detail on plate 145. Antifric-
tion devices of the lever design are included in the mechanism. This
can be seen in the view at the right on plate 145. The slip friction
devices are a part of the wormwheels shown on plate 154 and in de-
sign are practically identical with that used on the 10-inch sliding
mount, plate 113. For easy elevating of the gun, the antifriction de vice
is kept so adjusted that a 0.002 thickness gauge can be inserted under
the main trunnion. It will be observed on plate 145 that the two
mechanisms are rigidly connected by a cross shaft on which the chain
sprockets of each are mounted. One turn of the wheel moves the gun
through 35 minutes in elevation.

170. Traversing Mechanism. — ^The gun and cradle are swung be-
tween the side frames of the structural steel top carriage which is piv-
oted on the pintle at its forward end to allow a slight traverse. The
extent of this traverse is 5 degrees on each side of the center line.
Two handwheels mounted on the sides of the top carriage at the rear
connect by chains with a horizontal cross shaft and from this by bevel
gears to a horizontal longitudinal shaft which drives the traverse
pinion through a worm, wormwheel, and shaft. This mechanism is
shown in detail on plate 146. The rack and pinion are shown in detail
on plate 147. The location of the handwheel is shown more clearly
on plate 148. The greater part of the weight of the gun and top car-
riage is carried on the pintle, at which point the friction is reduced
through the use of a column of Belleville springs, shown on plate 54.
No provision is made in the design for the reduction of the friction
between the rear of the top carriage and the car body by any special
mechanism. The rubbing surfaces are simply kept well oiled. The
design of this contact at the rear is shown in the lower right hand
view on plate 146.

171. Gun Carriage. — The gun carriage includes the recoil, ele-
vating and traversing mechanisms described above, and two struc-
tural steel side frames with their connecting transoms to which these
parts are assembled. This carriage is pivoted on the main girder by
a heavy pintle which takes the horizontal component of the shock of
firing, but normally the weight is supported on a smaller spring-
supported pintle to reduce the friction of traversing. The pintle
design is shown on plate 54. The general design of the top carriage
is shown on plates 144, 147, and 148.

199

172. Car Body. — ^The car body consists of two plain plate girders
of ordinary design connected by suitable transoms and provided with
an operating platform at the rear. The exterior car body design is
shown on plate 143. The connecting transoms can be seen in the sec-
tion given on plate 54.

173. Anchorage. — ^The anchorage consists of a special groimd
platform made up in six sections and carried on a special ground
platform car. Each section consists of a large structural steel spade
and three wooden ties across which two nmning rails and two sup-
porting girders are fastened, plate 150. As noted above, these sec-
tions are carried in the special car, plates 151 and 152, which is pro-
vided with a special mechanism for placing the sections, 'and taking
them up and loading them. In placing a platform, a section of the
railway line of the required length is removed, pits are dug for the
spades and lined with sand or fine stone. The platform car is then
run up to the end of this space and one section after another is put
down, end to end, and bolted together. After one section is placed,
the platform car is run on to that section for the placing of the next.
On plates 153 and 154 a complete platform is shown installed and
ready for the placing of the mount.

174. When the platform has been bolted up and the sand and
rock well tamped around and under the ties and spades, the mount
is run on and so placed that 12 sets of clips, which can be seen on the
bottom of the lower cords on the side girders, plate 26, are just over
the similar sets of clips on the supporting girders of the platform,
plate 153. The 24 special wedges (12 on each side), which are carried
on the hooks which can be seen on the sides of the girders near the
lower cord, plate 155, are then placed between the car girders and
the platform girder and the mount is well wedged up and later
bolted to the platform. The wedges are each composed of three
triangular wedge-shaped sections, the middle one of which can be
moved with respect to the other two by a screw. The turning of the
screw forces the center wedge up and the other two wedges both out
imd down, thereby lifting a portion of the weight of the mount
from the trucks and attaching it rigidly to the platform through
the clips. This type of platform is particularly rigid and no dis-
placement whatever can ordinarily be observed even from very
heavy firing. It was a French practice to provide each mount with
two platforms both of which could be placed near each other in
a curved railway line, thereby giving a total traverse of 20 degrees
on the two platforms. The writer has seen a platform placed in
two hours after the section of track had been opened and pits for
the spades had been prepared. Much less time is required for their
removal.

200

175. Trucks. — ^The trucks, two in number, are eight-wheel loco-
motive type with inside journals, and the bodies are made up entirely
of structural steel. The journals are 6.693 by 12.2 inches and the
wheels 36.22 inches in diameter. The trucks are equipped with both
hand and air brakes. It will be observed that they are fitted with
the French type of buffer, plate 158. This was intended for service
in France. These buffers and couplings have since been replaced
by the standard M. C. B. type. The original center-pin design, which
can be seen on plate 54, was found to be unsatisfactory for service
on American roads, since it can not stand the strain of bumping of
the average American train. This has been modified to the heavy
center-plate design typical of American standard car equipment.

176. Ammunition Supply System. — ^The ammunition car used
with the Batignolles mounts is identical in design to that employed
with 8-inch railway mounts, plates 106 and 107. In service, this
ammunition car is placed directly behind the mount, plate 54. The
ammunition is placed on the operating platform of the mount by
means of the ammunition trolley. It is then picked up by the jib
crane, the design of which is shown in detail on plate 159, and trans-
ferred to a loading stand at the rear of the gun, plate 160, from which
it is slid down into the gun on a removable tray. The gun is loaded
at 5 degrees depression, the projectile being rammed by hand. The
design of the loading apparatus on the working platform of this
mount is very radically different from that provided on the French
Batignolles mounts, plate 162. On the French mount the projectile
is received directly from the ammunition car and drawn up to the
tray at the top of the inclined elevator. When this tray, which is
shown in an approximately horizontal position, is tipped up at the
rear, the projectile slides forward onjbo the ammunition stand which
can be moved back against the elevator. This ammunition stand
is then rolled forward by means of two handwheels, one of which can
be seen on the right hand side of the stand, bumping the breech of
the gun very hard. The projectile starts to slide into the breech of
the gun and is rammed by a mechanical rammer, operated by the
same two handwheels. It is felt that the simple modified design is
decidedly an improvement over the elaborate French design. A
closer view of the ammunition stand, breech of the gun, removable
tray, projectile tray, and powder bag of the American mount can be
seen on plate 161.

177. Maintenance. — No difficult problems of maintenance pre-
sented themselves to the French service on similar mounts, and it is
assumed that no serious difficulties will be experienced by the
American service. It will likely be necessary to check up occasionally
on the adjustment of the anti-friction devices to be certain that the
elevating mechanism is working at maximum efficiency.

201

178. Difficulties Involved in Sebvice. — ^It can not be said
that there are any particular difficulties involved in the service of
this design of mount. If the special ground platform car is kept in
fine working order the platform sections are not difficult to place,
and the time consumed in placing the platforms can not be said to
be excessive. One group commander with whom the writer was
able to consult a number of times had been in chaise of this type of
artillery since it had been placed in the field in 1915. He was a
naval officer and he was operating his artillery with navy personnel.
He was most enthusiastic about the BatignoUes design and was
positive that he had never experienced any serious difficulties either
of maintenance or service. A very striking attitude of commanders
who had operated continuously either the BatignoUes or the Glise-
ment type mounts was that each had become so thoroughly con-
vinced that the type that he was operating was the only type
worth having that he could not conceive of a reason for constructing
any other kind. This was especially so of the personnel operating
BatignoUes mounts. Although they had to admit that the sliding
type mounts were giving good service in the field, they could not
bring themselves to believe that it was a type of artiUery on which
construction should continue. The personnel operating sUding
artiUery held exactly the same point of view regarding their mounts.

179. Mebits. — ^The merit of this design is that it is exceedingly
weU balanced. It is true that there seems to be an excess of equip-
ment in* the ground platforms and platform cars, but with guns of this
caliber it is necessary to have a mount that is either provided with a
stable foundation or that can be operated on a curved track. The
difficulties incident to operating raUway mounts on curved tracks are
sometimes very great, and it is felt that what might be termed exces-
sive equipment in the platforms and platform cars, is less objectionable
than the difficulties involved in the laying of curved tracks. This
type of platform can be instaUed more rapidly than any other existing
type of platform for so heavy a gun.

180. Demebit. — ^The demerit of this mount, if it may be styled
such, is the very elaborate ground platform and platform car. It
seems quite probable that guns of this caliber might be placed on
mounts in which the horizontal component of the force of recoil can
be transmitted to the ground by means of struts at the rear, some-
what sinular to those used with 8-inch gun and 12-inch mortar
motmts. This would Ukely necessitate the provision of some jacking
equipment for lowering the mount, until portions of it were in contact
with the service rails or with auxiliary rails, for transmitting the
vertical component of the force of recoU into the track by other chan-
nels than through the trucks, but this would not be difficult. If such
a design can be made, and preliminary investigation indicates that it
can, then the BatignoUes design is too elaborate.

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7.— AMERICAN 12-INCH 50-CAUBER GUN ON RAILWAY MOUNT. (20)

181. This mount is of the French Glissement or sliding type modi-
fied to suit the American war-time manufacturing conditions. The
gun rests in trunnion hearings rigidly connected to the main girders of
the mount.. A general view and details are shown oh plates 163 to
184.

182. Gun. — The piece used with this mount is a 12-inch gun,
model of 1918, Bethlehem, of 50 calibers length, plate 15. It is
equipped with fixed' trunnions and counterweight on the breech end,
plate 165, to allow mounting the trunnions as near the breech as
possible. The breech block is of the Welin or step thread type,
plates 169 and 170.

183. Recoii;* Mechanism. — No recoil mechanism, in the ordinary
sense of the term, is used with this mount. The gun is fixed to the
girders, as noted above, and the entire mount slides back along the
track as a unit under the shock of recoil. Description of the arrange-
ment by which this is accomplished is given under ** Anchorage.''
Counter-recoil is accomplished by the same mechanism as traverse.

184. Elevating Mechanism. — Elevation from the loading posi-
tion, minus 4 degrees to plus 40 degrees, is secured through a seg-
mental circular rack attached to one side of the counterweight on
the breech of the gun. The pinion meshing ynih this rack connects
through a slip-friction device, a worm and wormwheel and sets of bevel
gears with two handwheels located on top Of the two side girders.
Any excessive thrust due to fire is taken up by the slip-friction device
and no dangerous strain can come on the gear. One turn of the
handwheel moves the gun through 0.625 degrees in elevation.
Details of this mechanism are shown on plate 172.

185. Traversing Mechanism. — No provision is made on this
mount for traversing the gun; pointing in azimuth is accomplished
by translating the entire carriage along the curved firing track. To
accomplish this, two translating mechanisms are provided, one on
each of the two inner eight-wheeled trucks. Each translating mech-
anism consists of a train of four gears and two sets of sprockets and
chains connecting the operating handwheel with one axle of the
truck, plate 117. The total ratio is 100 turns of the handwheel to
one turn of the truck wheel and on the shop test of the carriage, four
men on each operating Ivandle moved the mount at the rate of about
3 feet per minute. It is probable that this performance will be mate-
rially improved as the apparatus is limbered up by use. A clutch
is provided between the gear train and the chain so that the gears
can be disconnected when the. piece is fired. This is necessary in
order to avoid excessive speed in them as the car moves backward in
recoil. For traveling considerable distances, the chain between truck
axle and the rest of the mechanism is removed on all mechanisms.

227

186. An alternative power translating arrangement is provided on
the front span bolster of the mount. This comprises a 50-horsepower
gasoline engine and winch which are capable of exerting a pull of about
7,000 pounds; cable and sheaves are provided so that this may be
multiplied to the extent necessary to move the mount. It is not
possible to readily move the mount backward with this apparatus,
but if the mount is pulled somewhat too far forward, it can be run
back by the hand translating mechanism. One of the mounts, plate
168, is equipped with electric motors for driving the translating
mechanisms; the power is supplied from a 25-kilowatt gasoline
generator set mounted on a special recoiling base on the rear of the
working platform. It is possible to move the mount either forward
or backward by these motors.

187. Gun Carriage. — In this mount the gun carriage and car
body are incorporated in a single unit and are described in the next
paragraph.

188. Railway Car Body. — The railwav car bodv consists of
two large box girders built up of structural steel and connected by
transom plates. These girders are carried on span bolsters, plate
164, each of which, in turn, rests upon two trucks. Cast-steel trunnion
bearings are mounted on top of the girders and are provided with an
antifriction device which supports the gun on small trunnions for
elevating or depressing, but allows strains to be transmitted directly
to the main trunnion bearings during firing. Operating platforms,
loading apparatus, etc., are also provided on the car body. The main
girders rest upon span bolsters through a special center plate and
king bolt arrangement with removable center and side bearings. A
lever is provided on the side of the span bolster, plate 176, by moving
which these bearings can be withdrawn, so that a vertical movement of
5 inches between girder and span bolster is possible. This is provided
so that any possible sinking of the track and consequent lowering
of the main girder can not bring undue strain upon the truck.

189. Anchorage. — As noted above, this carriage is of the sliding
type and is not rigidly braced against the ground. It is fired from a
specially prepared track laid with extra long ties upon which are
set up eight lines of 12-inch, 55-pound steel I beams called bearing
stringers, plate 177. The weight of the mount is transferred from
the trucks to these stringers by means of 10 sleepers, which are special
wooden beams attached crosswise under the main girder. These are
attached to the main girder through lifting wedges, which permit them
to be lowered, so that they press upon the bearing stringers, or raised,
so that they clear and the weight of the mount is taken by the trucks,
plate 178. The lifting wedges, one of which is provided at each end
of each sleeper, consist of a fixed casting fastened to the underside
of the side girder, a movable wedge attached to the sleeper and capable

228

of vertical movement only, and a secon(I movable wedge between these
two, which can be moved horizontally by means of a screw threaded
through its center, bevel gears, and operating lever. As the lever is
turned, the upper wedge is moved along by the screw and the lower
wedge with sleeper is raised or lowered accordingly. Each sleeper
consists of a plate steel carrier into which are bolted three heavy
wooden beams at each end. While the gun is in action the two ends
of the sleeper are supported on the lower wedges of the lifting-wedge
mechanism described above. For traveling the sleepers are slid out
sideways with the help of sleeper cranes and are loaded separately.
For firing the special track with bearing stringers as above described
is laid on an Il-degree, 48-minute curve. The mount is pushed
approximately to position on this track by means of a locomotive
and is adjusted exactly by the translating mechanism. The sleepers
are inserted and the weight of the mount is transferred largely to
them by the operation of the lifting wedges. The gun is then fired
and the mount slides backward along the track for a short distance.
The wedges are raised and the mount is run forward to its original
position by the translating mechanism, or by the gasoline winch
already mentioned. Except for the span bolster center plate arrange-
ment and the character of the wedge mechanism, this anchorage
arrangement does not differ materially from that employed in the 10-
inch sliding mount.

190. Trucks. — Four eight-wheel trucks, plate 179, are provided
for this mount. They have structural side frames, cast-steel bolsters,
5.5 by 10 inch journals, and 30-inch wheels. The two outermost
trucks are provided with air brakes, plate 180, and the two innermost
with translating mechanism, as described under Traversing mecha-
nism. Semi-elliptic springs are provided over each journal box.

191. Ammunition Supply System. — The ammunition car used with
this mount, plate 181, is the standard Railway Artillery ammuni-
tion car. Special fixtures are provided, however, plate 182, for the
12-inch ammunition. The car is kept down the track at some distance
from the mount itself, and a special shuttle car, plate 183, which is
pushed by hand, is employed in transferring ammunition from the
ammunition car to the mount. In use the shuttle car is run up
against the end of the ammunition car and the trolley in the latter is
run out over it. Ammunition is picked up from the interior of the
car, run out, and let down directly on the shuttle car. The shuttle
car is then pushed along the track by hand to the mount. The ammu-
nition is picked up by means of the jib crane mounted on the rear
span bolster and is transferred to an ammunition tray which runs
on an inclined track from the back end of the main girders to the breach
of the gun. This tray is provided with a buffer, so that when it is
released it may run down the track and be stopped at the breech of

229

the gun without undue shock. The projectile slides on and seats
iteeU in the gun. The loading angle is minus 4 degrees. The general
arrangements for loading, as described above, are shown on plate 184.
192. Maintenancb. — Experience in hauling the mount over the
road has shown that there is considerable wearing of the two side
girders relative to each other which causes binding of the trunnion
bearings. A complete steel plate decking is being added along the
top of the girders to eliminate this. A similar weaving in French
mounts has resulted in the breaking of trunnion caps. None of the
mounts has yet seen sufficient service to develop serious troubles
except as just noted. It is probable when these difficulties are reme-
died that no serious problems of maintenance will present themselves
in field service.

Plate 163

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8.— AMERICAN 12-INCH HOWITZER ON RAILWAY MOUNT. (21)

193. This entire design was made up in response to a request
from the Expeditionary Forces in France for a long 12-inch mortar
with a range of 20,000 yards, mounted on a carriage that would be
emplaced in a manner similar to the 8-inch gun and 12-inch mortar
carriages, and from which the mortar could be fired over either end,
and with a traverse of from 20 to 30 degrees on each side of the center.
Accordingly a cannon of 20 calibers length and capable of being
operated at a pressure that would give sufficient muzzle velocity
to attain the desired 20,000 yards range was designed and was
mounted on a carriage similar to the carriage used for the 8-inch
gun and 12-inch mortar. The difference between the details of this
and the previous designs will be pointed out later. It is probable
that this represents the limit of the ability of the designer to com-
bine in one unit a gun of so great an elevation as 65 degrees and a
traverse of 360 degrees from a carriage equipped with self-con-
tained emplacing facilities which enable the mount to be emplaced
for action on any existing standard track in less than one hour.
From the standpoint of these characteristics of great muzzle energy,
high elevation, wide traverse, and rapid emplacement it is felt that
this is among the most valuable, if it is not actually the most valuable,
mount now in the possession of the American ^Vrmy. Recent inves-
tigations indicate that with the addition of a new cradle it will be
possible to operate an 8-inch, 50-caliber gun from the same carriage.
The mount and its details are illustrated on plates 185 to 215 and
125.

194. Gun. — The gun for this carriage is a 12-inch, 20-caliber
howitzer, model 1919, of built-up design. This howitzer has, at
various times, been termed a *'long mortar^' and a " howitzer*'; in
this treatment, however, it will be known as a howitzer. It is fitted
with a breechblock of the interrupted thread design, which is fitted
with a mechanical firing mechanism. It has 108 grooves and the
rifling twists to the right, the pitch increasing from one turn in 40
calibers to one turn in 20 calibers. Its probable life is 500 rounds.

195. Recoil Mechanism. — The recoil mechanism, plates 196 and
197, comprises two hydraulic recoil cylinders fitted into the cradle
on either side of the center at the bottom* and a pneumatic recuper-
ator attached to the top of the cradle in the center. The maximum
length of recoil is 37.5 inches. The design of the recoU cylinders,
plate 198, is not unlike that of the cylinders used on previously
designed mounts. The design of the recuperator, plate 199, is
essentially the same as the recuperator described in detail under the
12-inch mortar. An air bottle is carried on the left side of the
carri^e and is permanently connected by small tubing with the
rear of the recuperator cylinders, y>late 197. Gauges for measuring

252

the initial air and liquid pressures are mounted on the left side of the
cradle. A liquid pump, plate 200, for maintaining the floating
piston in the recuperator in its proper relative position is likewise
moimted on the left side of 'the cradle between the two gauges.

196. Elevating Mechanism. — ^The elevating mechanism com-
prises a circular rack bolted to the right side of the cradle, a pinion
meshing with this, and a train of spur gears leading to the single
handwheel mounted on the right side of the carriage, plate 201.
As a substitute for the usual slip friction device, this mechanism
includes a brake on the handwheel of a design similar to that of
the service brake of an automobile. The drum is a part of the hand-
wheel, plate 201, and the brake grips it tightly except when the
foot pedal, plate 202, is pressed down. This elevating mechanism
comprising spur gears only, follows the design of the elevating
mechanism of the 16-inch howitzer mechanism which was found
particularly efficient. An antifriction device, plate 203, is mounted
with each trunnion to reduce the effort required in elevating and
depressing the gun. The principle of the operation of this device
is the same as that of other devices already described, although it
differs in the details of its design. The elevation quadrant used
with this moimt is the special elevation quadrant, model 1917,
plate 173, designed for use with railway mounts.

197. Traversing Mechanism. — ^The traversing mechanism com-
prises a circular rack bolted to the inside of the base ring, plate 196,
a pinion meshing with this, and a vertical shaft leading to the worm
wheel, worm and hand wheel, plate 204, moimted on the left side of
the carriage. The ratio of the gearing is one turn of the handwheel
for 1.028 degrees of traverse. The panoramic sight used with this
mount is identical with that shown on plates 174 and 175.

198. Gun Carriage. — The top of the gun carriage comprises a
cradle of grid-iron design, plate 197, a top carriage body made up of
two cast steel side frames and light front and rear transoms connect-
ing these, plates 186, 187, and 196, a structural steel working plat-
form carrying the ammunition table and crane, plates 196, 205, and

206, all of which are carried on a cast steel racer, plate 196. Atten-
tion is invited to the differences in the details of the design of this
racer, plate 196, and the racers for the 8-inch gun and 12-inch mor-
tar, plates 33 and 38.

199. Railway Car Body. — The railway car body, plates 196 and

207, is in its details quite unlike that of the 8-inch gun and 12-inoh
mortar. The 8-inch gun and 12-inch mortar car bodies are built
entirely of structural steel. Even with the best work that it was
possible to secure on these mounts, the bed on which the base ring
rests was invariably so buckled as to require an undue amoimt of
lining up, and even after being properly lined, was not satisfactorily
rigid. In this design the car body is composed of three parts,

253

the two ends of structural steel and the centt>r a steel casting.
It will be noted that the casting has sufficient drop at the center
to permit it to rest on the firing beams^ sleepers being used only
at the ends. It is likewise satisfactorily rigid, and eliminates
entirely the necessity for lining up already mentioned for other
mounts. The structural steel ends are bolted to the center section.
It is possible that the car body of this design can not be so quickly
manufactured as if it were entirely of structural steel, but it is be-
lieved that the advantages in having so rigid a base outweigh the
disadvantages in time of construction. Attention is called to the
fact that this cast-steel section is open in the center permitting the
gun to recoil practically to the level of the ties. Comparison of this
mount with the 8-inch railway moimt will show that this principle
of permitting the gun to recoil through the base ring of the top car-
riage and center ring of the car body has resulted in decreasing con-
siderably the distance from the center line of the trunnions to the
top of the rails. This, of course, decreases the distances between the
trunnions and the point at which the outriggers are attached and
when firing at wide angles to the track* the line of recoil is more
nearly in line with the outriggers and the mount is much more stable.
The draft gear, plate 208, is so designed as to reduce the severe buflFing
shock when the mount is being made up into a train or when it is
traveling.

200. Anchorage. — The system of anchorage is essentially like
that of the 8-inch gun and 12-inch mortar mounts. The outriggers,
plates 186, 187, and 209, are attached to the car body by means of
universal joints giving a much wider range of action than the ball
joints used on the other mounts. Tension rods permanently at-
tached to the car are provided for each of the struts to counteract
certain tendencies of the car to jump when gun is fired at low eleva-
tions. In emplacing the mount for action, built-up beams are placed
across the rails, plate 210, and the car is raised by means of four
screw jacks, plate 211. When the carriage has been raised a sufficient
amount, the built-up steel firing beams are placed on the ties outside
the rails with two sleepers across each end. The mount is then
lowered until it rests on these sleepers and beams. The cast-steel
center section of the car body rests directly on these structural-steel
firing beams. In transit the firing beams, sleepers, cast bearing
plates and floats are arranged on the mount as shown on plate 191.

201. Trucks. — ^This mount is provided with two 6-wheel trucks
with 28-incli steel wheels and 5.5 by 10-inch outside journals, plate
212. The trucks are equipped with both hand and air brakes, plates
213 and 214.

202. Ammunition Supply System. — Ammunition tables and trays
are built into each end of the car body, plate 186. A loading stand
is built into the working platform in the center at the rear, plate 215,

254

and projectiles are transferred to it from the table on the car body
by hand operated jib cranes, plates 215 and 216. Experience on
railway artillery in France resulted in the specification that the am-
munition supply system for this mount be so designed as to permit
of operation of the gun from either end of the car with equal facility.
The gun can be traversed through 360 degrees and no matter how it
may be run in on its emplacement, it can be operated in any direction.
As long as the gun operates within the scope of either end of the car,
ammunition can be supplied directly from the ammunition car to
the tray at the end and from the tray by means of the cranes to the
ammunition table on the top carriage. When the gun is operated at
wide angles to the track, after each third shot the gun carriage must
be traversed back within reach of the shell tray on the car. This is
not a disadvantage, however, since the carriage can be traversed
easily and quickly and no time will be lost. The tables on either
end of the car, plates 189 and 190, will hold seven projectiles each,
and the ammunition stand on the working platform will hold three
projectiles.

203. Maintenance.— It is not believed that any difficulty will be
experienced in the service of a mount of this design. Quite probably
the attention required on the recoil cylinders and the recuperator?
together with the minor service to keep the elevating and traversing
mechanisms in good shape will constitute the bulk of the mainten-
ance.

204. Merits. — For a gun of this caliber and length, this is the
best designed in all of its details that the writer has seen in any army.
Its recoil mechanism is unusually fine, the elevating and traversing
mechanisms are rapid and efficient; the car-body design, involving
the use of a centrally cast-steel section is excellent; the details of the
anchorage system are very good and the ammunition supply system
equally good. When handled \\ ith care and by experienced artillery-
men, this gun ^^ill probably render more efficient service than any
other railway mount possessed by the American Army.

205. Demerits. — ^There seems to be no ground for criticism of
any part of the mount except possibly the elaborate design of the
cradle. The objection that is raised to this design is the time re-
quired to make patterns, the time required to make the castings, and
the difficulties involved in making perfect castings. Under peace-
time manufacturing conditions such a design may not be due for
much criticism. Under stress of w^ar-time conditions, how^ever, it
can not be manufactured with satisfactory speed, and is likely to tie
up shop facilities for an undue length of time. Cradles of foreign
design have been observed which are practically smooth cylinders.
It is quite true that such cylinders are not as rigid as the design imder
discussion, but they have been used with 15-inch 45-caliber guns, and
have not developed serious faults.

255

Plate 185

12 IN. HOWITZER RAILWAY MOUNT- MODEL 1919
TOTAL WEIGHT 199,249 LM

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9.— 14.INCH GUN ON RAILWAY MOUNT, MODEL E. (22)

206. This is a mount the design of which was practically finished
prior to our entrance into this war. It was designed primarily for
service in the coast defenses, although a number of special provisions
were made for its service as a field mount apd even those features
which adapt it especially for coast defense, adapt it likewise for certain
types of field service. It can be operated either as a sliding or as a
fixed emplacement mount. Only one mount of this design has been
finished, but it has made so favorable an impression from its per-
formance in recent tests against a moving target, at a distance of
6,QP0 yards, when the difficulties of following a rapidly moving
target are extreme, that it is probable that a new moiuit embodying
most of its desirable features, as well as other features found impera-
tive for field service, will be made up very shortly. General views
are shown on plates 217, 218, 219, and 220.

207. Gun. — ^The piece used on this mount is a wire-womid 14-inch
gun, model 1919, of 40 caliber length. It is provided with an inter-
rupted thread breech, which is fitted with a mechanical firing
mechanism. There are 126 grooves and the twist of the rifling is
to the right, progressing from one turn in 50 calibers to one turn in
25 calibers.

208. Recoil Mechanism. — ^The recoil mechanism is of the hydro-
spring type and is composed of one hydraulic recoil cylinder attached
to the bottom of the cradle in the center, and of the design shown on
plate 221, and six spring recuperator cylinders arranged about the
cradle and of the design shown on plate 222. This recoil mechanism
has functioned very satisfactorily in all of the tests so far conducted.
It is quite probable, however, that a pneumatic recuperator will be
substituted for the spring recuperator on the new design that will
be made up for other 14-inch guns. There are no features in the
design of either the recoil cylinder or spring recuperator that are
unusual. The maximum length of recoil is 60 inches. A by-pass
providing an additional oil passage between the end of the buffer and
outlet on the bottom of the cylinder is shown on plate 221. This is
provided to permit of an adjustment to secure the full recoil of the
gun at low elevation as well as for reduced powder charges.

209. Elevating Mechanism. — Provision is made for elevating
the gun from its loading angle, zero degrees, to a maximum eleva-
tion of 30 degrees The details of the elevating mechanism are
shown on plates 221 and 223. This elevating mechanism is essen-
tially the same in design as that provided on the 14-inch Navy
mounts, Marks I and II. It will be observed on the above noted
plates that the mechanism is made up of one large screw hinged to
the bottom of the cradle by means of a yoke and trunnions and
passing through a large nut in the oscillating housing which is in

287

turn supported by its trunnions in bearings attached to the car body.
This nut is provided with a ball thrust bearing as shown on plate 223;
and is driven by miter gears which communicate with the handwheel
through the horizontal cross shaft and two more sets of miter gears.
The elevating handwheel is mounted on the right side of the car-
riage just behind the trunnion. Each trunnion is equipped with an
antifriction device of the design shown on plate 224. This is of the
rolling wedge or knife edge type and again is almost identical in
design with the antifriction device provided on the Navy 14-inch
mounts, plate 270. It is composed of a fulcrum arm whose rounded
lower end rests in a bearing block which in turn rests on the adjust-
ing wedge. The upper end of the f ulcrmn arm is rounded to a radius
equal to the distance from the center of the lower end to the center of
the top, and bears directly against the under side of an extension of
the main trunnion. Both the fulcnun arm and the trunnion are fitted
with gear-toothed segments which mesh with each other and prevent
slipping of the arm. The device is adjusted by means of the wedge
under the bearing block at the bottom of the arm. When properly
adjusted; this device carries the weight of the gun while it is being
elevated and depressed, thereby reducing considerably the effort
required. When the gun is fired the force of recoil is transmitted,
even at the maximum firing angle of 30 degrees, almost entirely into
the inain trunnion bearing. This mechanism is inferior to the type
used in the service of the other mounts already described, in that it
contains no flexible parts that can bend or be compressed imder the
force of recoil and permit that force to be communicated more easily
and directly to the main trunnion bearings. One turn of the slow,
operating handwheel elevates the gun through 0.33 degree and one
turn of the fast-operating crank elevates the gun through 0.545
degree.

210. Traversing Mechanism. — This mount can be traversed
through 360 degrees by means of a mechanism, the design and
details of which are shown on plates 225, 226, and 227. The entire
mount rests by means of four conical rollers on a cast-steel base
plate. To the center of the base plate is bolted a pintle which takes
the horizontal component of the force of the recoil ; gears are cut on
the inside of the roller path to serve as a traverse rack. The trav-
erse pinion is cut in the bottom end of a vertical shaft which can be
raised for traveling, or lowered to mesh with the traversing rack for
traversing the moimt. This shaft passes through and is driven by
the large horizontal miter gear, as shown on plate 227, which is in
turn driven through miter gears by the two handwheels on the sides
of the carriage. The gear case through which the horizontal driv-
ing shaft passes on the left side of the carriage, plate 227, contains a

18176S-21 ^19

288

large miter gear, loose on* the shaft, but which may be thrown into
gear with the shaft by the foot-pedal operated clutch. When the
clutch engages the miter gear, the traversing mechanism is operated
by the handwheel somewhat to the rear of the handle and shown
on plate 218. This gear is used for the final fine adjustment.

211. It has been noted before that the gun can be fired without the
use of a firing platform to an elevation of 22 degrees. To secure any
great amount of traverse imder this elevation, it is of course neces-
sary to operate the mount on a curved track. For fine adjustment,
a car body traversing mechanism of the design shown on plates 228
and 229 is used. It will be observed here, that cast-steel body bol-
sters shown in detail on plate 230, riveted into each end of the car,
carry a traversing beam which is fixed with respect to the truck
when the lifting bolster is down. Between this traversing beam
and the body bolster are two rollers, 5.33 inches in diameter and 23
inches in length, on each end of which are cut spur gears which mesh
with racks attached to the body bolster and the traversing beam.
The traversing beam is connected with the handwheel on the left side
of the carriage, plates 218 and 228, by means of a screw and spur gears.
The mount is capable of being traversed 0.25 degree on each side of
the center, at each end of the car, by means of this mechanism, thereby
securing a total traverse of 1 degree. One turn of the handwheel
moves one end of the car through 0.093 degree. As the handwheel
is turned, the traversing screw moves either in or out of the travers-
ing beam. As noted before, the traversing beam is fixed with respect
to the trucks the car body must therefore mov on the traversing
rollers.

212. Gun Carriage.-^Iu this mount the gun carriage is incorpo-
rated with and is a part of the car body. The gun is carried in a
cast-steel cradle which is swung directly by means of its trunnions,
between the side girders of the car body.

213. Car Body. — ^The car body is made up of two single-web
structural steel side girders connected by a series of structural and
cast steel transoms, plate 230. The cast-steel body bolsters at the
front and the rear, the cast-steel pintle bearing in the center at the
bottom, and the cast-steel jack bolster at the rear serve further to
stiffen it. Two cast-steel side frame yokes serve further to stiffen the
car body at the top and one carries the forward end of the I-beam
ammunition trolley, plate 243.

214. Anchorage. — ^The mount may be operated to an elevation
of 22 degrees without the use of auxiliary anchorage equipment, if
desired. To this elevation it may be operated as a sliding type mount.
On plates 231 and 232 are shown the cast-steel sliding shoes which
are bolted to the bottom of the lower chords of the side girders at the
front and the rear. These shoes bear on two auxiliary rails placed on

289

the ties one on the outside of each of the service rails. When ready
for firing the mount is let down until the entire weight rests on the
auxiliary rails through these shoes. In a series of trials that have
been made, the length of recoil varied from 11 to 17 feet.

215. For firing above angles of 22 degrees, it is necessary to place
the mount on the cast-steel base ring, the design of one half of which
is shown on plate 233. . This base ring may be laid either on a con-
crete sub-base or on rock ballast. When placed on rock ballast, it is
necessary to brace it against lateral movement by means of 64
steel piles, 4 feet long, driven around its circumference. The base
ring is in halves and in traveling is carried on a standard flat car, as
shown in plate 234. The full capacity of a 160-ton locomotive crane
is required to handle it in process of installation. It is first removed
from the car and placed on the ground beside the emplacement, as
shown on plate 235. On plate 234 a lifting eye will be observed at-
tached to the hinge pin between the two sections. After the base
has been placed on the ground, it is picked up first by means of this
eye, as shown on plate 236, after which two chains are attached to
the two half segments. The platform is then spread, plate 237, and
laid in place on the leveled ballast surface of the prepared position,
plate 238. The two segments are then bolted together with eight
bolts on each side of the center and the steel piles driven around the
circumference, plate 239. Four special rail sections are placed over
the conical roUer path and are bolted to the rails of the approach
track. After these rail sections are installed, the mount is run into
position over the emplacement and lowered until the traversing
rollers rest on the roller path and the pintle engages with the pintle
bearing, plate 240.

216; The moimt is lowered by means of two identical lifting de-
vices installed on the front and rear trucks and of a design shown on
plates 228 and 229. Above the center of the front truck, plate 218,
a capstan mounted on the shaft of the pinion, which drives this lifting
gear, can be seen. This pinion meshes with two large spur gears
which are attached to the ends of identical screws which screw into
the lifting bolster. As the capstan is turned and drives these screws,
the bolster is raised or lowered with respect to the car, thereby lower-
ing the car onto, or raising it from the emplacement. This device
is supplemented by a hydraulic lift, incorporated in the center plate
of the truck. However, when this is used the movable bolster must
be raised or lowered by hand to maintain the side bearing clearance
and prevent the mount from overturning. The lifting bolster is shown
in its traveling position on plate 228. On plate 229 it is shown as
located when the mount is resting on the emplacement and the trucks
are. removed or ready to be removed. The eight conical traversing
rollers, plate 240, are removed in traveling.

290

217. When the lifting bolsters are raised the mount can be trav-
ersed until the rear end is over the supports, plate 241. This support-
ing device with the support beams is shown on plates 242, 243, and

244. The cast steel support beams are made up in segments and are
placed on short sections of I-beams which rest directly on stone bal-
last. A cast steel transom carrying two hydraulic jacks and one
screw jack is riveted to the rear of the car body. These hydraulic
jacks have swinging shoes which rest on the support beams and serve
to prevent the mount from turning over in firing. Tests have been
made which prove that the mount can be operated without supports
of this kind when the base ring is bolted to a concrete subbase. The
design of the hydraulic support cylinder is shown on plates 244 and

245. No special mechanism is provided for raising or lowering the
hydraulic cylinders. They can easily be raised or lowered by any
sort of lever, such as a crowbar, and move easily when moved very
slowly. In preparing for action the supporting beams are leveled
very carefully and the hydraulic jack shoes are lowered until they
bear on the greased top surface of the supports. A small cable is
attached to the top of the movable cylinder and passes over the top
of thp pulley to the counterweight which balances its weight. The
cylinder will remain in any position. As the cylinder moves up or
down, the oil between it and the ram must pass through the valve
shown in the center of the bottom of the ram, plate 245. Any at-
tempt to move the cylinder rapidly as is the case when the gun is
fired, simply serves to close this valve and prevent the cylinder from
moving. Thus the cylinder can be brought down until its bearing
plate rests on the support segments, and inasmuch as it exerts no
pressure, no difficulty is caused in traversing; but the cylinder fur-
nishes a positive support in firing, since as noted above, any attempt
to move it rapidly closes the valve in the ram. The top surface of the
support beams is kept well greased.

218. Trucks. — ^The trucks are constructed of structural steel and
steel castings and carry four axles each with 6 by 11 inch outside
joiunals and 31-inch wheels. Both hand and air brakes are provided.
The two trucks are identical in design. The axles are equalized
throughout, thereby transmitting the load evenly throughout the
entire truck. The design is shown on plates 246, 247, 248, and 249.

219. Ammunition Supply System. — ^The design of the loading
gear is shown on plates 250 and 251. It will be seen on the first plate
that the projectiles can be picked up from the groimd or from a plat-
form at the rear of the carriage by means of a chain hoist carried on
an I-beam trolley. The projectile is carried forward and placed on
the shot truck, the wheels of which ride on angle iron rails. The
shot truck is run forward with as great a velocity as possible until its

291

buffer strikes the breech of the gun, when the projectile slides on into
the powder chamber. The projectile is then rammed by hand. The
powder charge is picked up from the rear and placed on the shot
truck by means of the same hoist. The shot truck is run forward to
the breech of the gun and the charge pushed into the chamber by
hand. A speed of firii^ of seven shots in 14 minutes has been at-
tained in recent tests. In these tests it was necessary to lift the pro-
jectiles from the ground. Had the projectiles been located on a plat-
form, level with the working platform of the carriage, it is believed
that this time might have been reduced to one shot per minute.

220. Maintenance. — ^In the service that this one mount has so far
seen, it has proved very sturdy and practically no maintenance except
the ordinary attention required for the various mechanisms has been
necessary. It is believed that no serious difficulty would have been
experienced with mount of this design even imder the severe condi-
tions prevailing in France during the war.

221. Difficulties Involved in Service. — The one feature of this
mount which might cause what may be termed difficulties in service,
is its emplacement for high angle firing. This emplacement required
the full capacity of a 160- ton locomotive crane for installation and
removal. To those acquainted with field service of heavy artillery
in this war, it is not certain, however, that this constitutes a diffi-
culty that is serious. A heavy locomotive crane was to be included
in the equipment of the organization maintaining railway artillery
in the park of the Railway Artillery Reserve in France, and since such
a crane is required for the ordinary service of maintenance, it would
of course, be available for the installation of the equipment of such a
gun as this, of which any army would certainly have only a limited
number. This emplacement permits of operation at 90 degrees to,
any existing railway line and it can be installed in less than a day.
The platform used with the Navy 14-inch mounts Mark I, and with
French 340-inillimeter guns and 400-millimeter howitzers required
at least two days for installation and the maximum traverse that
can be secured in any one position with these moimts is not more
than 10 degrees. As a consequence, it is felt that no serious diffi-
culties would be experienced in the service of this mount for land
warfare. Trials have proved it particularly easy of service and
efficient for coast defense.

222. Merits. — ^The merit of this design is that it embodies most
of the features found desirable in mounts for large guns during the
present war. For a gun of this size, it can be emplaced in a very
reasonable time and it can be trained on a target in any direction
from any position: It can be operated from a curved track as a
sliding mount and has an internal car traversing mechanism. The

292

speed of operation developed in recent tests of 7 shots in 14
minutes with probability of its reduction to 1 shot per minute is
excellent.

223. Demeritb. — The only criticism that occurs to the writer in
connection with this design is in the matter of the limited elevation
to which the gun can be operated either as a sliding or as a fixed
emplacement mount. The maximum elevation for operation as a
sliding mount is 22 d^rees, and 30 degrees for operation as a fixed
emplacement mount. The limit for service as either a sliding or
fixed emplacement type of mount should be at least as high as 45
degrees and preferably 50 d^ees.

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10.— AMERICAN 14-INCH GUN, NAVAL RAILWAY MOUNT, MARK L (23)

224. This mount is of the cradle recoil car traverse type. The
gun is mounted in a cradle having combined hydrospring and hydro-
pneumatic recoil mechanism. This cradle is supported in turn by
its trunnions on two cast-steel deck lugs, similar to those used in the
turret of the battleship, which are attached to the side girders of the
carriage. The structural steel carriage is carried on two structural
steel span bolsters which in turn rest on two 3-axle trucks each.
The mount fires from its trucks' at elevations between 10 and
15 degrees. When fired from its trucks it is possible to traverse the
mount only by operating it on a curved track. At elevations between
15 and 45 degrees it is necessary to remove the trucks and operate
the mount on a fixed emplacement. When operated on a fixed em-
placement the internal car traversing mechanism is used to train the
gun in azimuth. General views are shown on plates 253 to 263.

225. The guns used on these mounts are 14-inoh naval rifles, Mark
IV, Modification 1, of 50-caliber length. The gim is made up of 10
main parts, including a tube jacket, hoops, breech bushing, and
locking rings. The rifling has a right hand twist increasing in pitch
from one turn in 50 calibers at the origin, to one turn in 32 calibers at
a distance of 574 inches from the origin. From this point to the
muzzle the twist is uniform; that is, one turn in 32 calibers. Holes
are drilled in the breech recess pointing toward the center of the
powder chamber to admit air for ejecting the gases from the gun.
The gas ejector valve is attached to the breech face of the gun,
plate 256. The gun is provided with a breechblock of the Welin or
stepped screw type and DeBange system of gas check. The breech
recess is threaded' and slotted into 16 sectors, one blank and three
thread sectors being included in each of four groups, and only one-
sixteenth of a revolution of the block is required to release or look it.
The block when rotated falls open by its own weight, dropping at
an angle of 16 degrees to the right of a vertical line thrpugh the center
of the bore and is checked by a combined spring and air buffer,
shown at the bottom of the breech lug, plate 256, and shown in detail
on plate 257. The breech is closed by air pressure admitted into
the combined buffer and closing cylinder. The breechblock is fitted
with a mechanical firing mechanism of the design shown on plate 258.

226. Recoil Mechanism. — ^The recoil mechanism consists of one
recoil and four spring cylinders arranged about the cradle and of a
design shown on plate 259. The recoil cylinder is the usual hydraulic
brake, but uses throttling rods, three in niunber, instead of grooves
or bars. The spring tubes each contain double spring columns,
plate 267, divided into six sections and the ends of the spring rods
are provided with air-tight pistons so that compressed air can be used
to aid in returning the piece to battery at high elevations. When the

329

gun is being fired at elevations between 10 and 15 degrees, the mount
recoils along the track a distance of from 30 to 40 feet. Under such
circumstances the mount is returned to its firing position by a winch
mounted on the front span bolster. The maximum length of recoil,
at the maximum elevation is 44.5 inches. When operated at ele-
vations between 15 and 45 degrees, it is necessary to place the mount
on a fixed emplacement which includes a pit to recc&ve the breech of
the gun at high elevations and into which the gun may recoil. The
recoil and recuperator pistons are all attached to a yoke which is
slipped over the breech of the gun from the rear and is secured to a
collar on the gun, by means of a bronze locking ring.

227. Elevating Mechanism. — Elevation from 0 to 45 degrees is
secured through a heavy screw hinged to the cradle at the breech
end and working in a nut carried in an oscillating bearing at the center
of the girder. This nut is rotated from a handwheel on the side of
the mount by means of .three sets of mite gears and intermediate
shafting, plates 268 and 269. One revolution of the handwheel
moves the gun through about 20 minutes in elevation. The elevating
mechanism includes antifriction devices of the design shown on
plate 270. It was mentioned under the head of Elevating Mechanism
in the description of the 14-inch railway mount, model E, that the
antifriction device of that mount is practically identical with that
used on the Navy mounts. This mechanism works efficiently in
reducing the trunnion friction, but as mentioned before, does not
embody those flexible elements which permit the shock of recoil to
be transmitted directly into the trunnion bearings without excessive
strain on the antifriction mechanism.

228. Tbaveksinq Mechanism. — When the gun is fired at low
elevations from the wheels, traverse is secured by moving the mount
along a curved track by means of a small winch located on the front
bolster. When the gun is to be fired at high elevations from the
emplacement the latter is so placed as to give the gun approximately
the correct azimuth. Small changes in azimuth are effected by
traversing the mount on the jacks and jacking beams which support
it, and around the pintle of the emplacement, by means of a screw
located on the rear beam. A traverse of 2.5 degrees on each side of
the center line can be secured with the jacking beams in any one
position. It will be observed on plate 23 that when the gun is
operated at high elevations, the carriage is supported on four hy-
draulic jacks placed under the ends of the two jacking beams. If
it is desired to secure more than the total of 5 degrees traverse on
one emplacement, the jacks can be lowered and the beams run to the
extreme limit in the direction in which it is desired to traverse each
end of the mount, and the jacks moved until they are in their proper
position under the ends of the beams. By this procedure it is pos-
sible to secure a total traverse of about 10 degrees on one emplace-

330

ment. It would of course be possible to move the jack supports
and secure greater traverse, but the emplacement is not so con-
structed as to take safely the shock of recoil at any very great side
angle. The details of construction of the rear jacking beam with its
traversing screw are shown on plate 271.

229. Gun Carriage. — ^The gun carriage is incorporated in the car
body and the twt> are described together in the* next paragraph.

230. Car Body. — ^The car body, plate 253, consists of two heavy
single web structural steel girders connected by structural and cast
steel transoms. The cradle is swimg by means of its trunnions in
the bearings of the deck lugs attached to the side girders. The
elevating and traversing mechanisms already described, are likewise
assembled to the girders. A bullet proof cab of 0.25 inch steel is
constructed over the rear of the girders to shelter the personnel -
This is the only mount that the writer has observed that is so heavily
protected with armor. The Italian 38-centimeter railway mount
has a shelter of armor plate over the working platform, but no side
plates.

231. Anchorage. — When the gun is operated at elevations be-
tween 10 and 15 degrees, no anchorage other than wheel friction is
required. For operating at high elevations a pit is dug, a bed of
timbers is provided at each end of the car body and the weight of
the car is transferred to these beds by hydraulic jacks placed between
them and special jacking beams incorporated in the car body. The
pit is about 9 feet deep, plate 272, and is lined with timbers. The
timbers at the rear end of the pit are united into a mat or spade and
are connected to the pintle near the center of the girders of the mount,
by structural members and a trunnion bed plate casting so that the
horizontal component of the shock of firing is taken against them.
On plate 273 the emplacement is shown complete and ready to receive
the mount. This firing platform is similar in general design to that
required for the 340^millimeter French gun and the 400-millimeter
French howitzer railway mounts, and for the American 16-inch
howitzer when operating at its maximum elevation. The braces
between the cast steel pintle block and the timber mat or spade in
the pit for the three moimts just mentioned, are made up of l^i-incL
square timbers. The braces for this mount are built up of structural
steel.

232. Trucks. — ^The four trucks are identical in construction and
are 6-wheel locomotive type with 9 by 12-inch journals and 36-inch
wheels. Each truck is provided with hand brakes. The details of
construction are shown on plate 274. These trucks are connected in
pairs by structural steel span bolsters and the ends of the main
girders pivot on these span bolsters.

233. AMMUNmoN Supply System. — ^For the service of ammunition
an I-beam trolley track is so arranged along the roof of the cab of the

331

mount, plate 253, that it can be pushed to the rear and made con-
tinuous with a similar track in the ammunition car, plate 275, which
is coupled just behind. The shell is picked up in the ammunition
car by a trolley hoist, run along into the cab of the mount and let
down onto the ammunition tray, plate 276. This tray runs on
wheels along a track to the breech of the gun. It is provided with a
buffer which brings it to a stop when it hits the breech and the shell
continues on into the chamber of the gun and is arranged by hand.
The gun is loaded at 0 d^rees elevation.

234. Maintenance. — ^Two serious defects in the design of this

mount result in considerable difficulties in maintenance. First, the
axle loads, especially on the front trucks, are so great as to make
it practically impossible to transport the mounts for any great dis-
tance at a speed greater than from 5 to 10 miles an hour without
more bearing trouble than is normally expected and certainly without
more than can be tolerated in a mount carrying a gun of this value.
Second, the structural steel members which connect the spade and
the trunnion bed plate are so flexible as to give trouble in handling.
They are inclined to buckle easily. An additional difficulty was
encountered as a result of covering the entire working platform with
armor. A great amount of moisture condenses on all metal surfaces
within the cab and does not evaporate very rapidly because of the
lack of circulation of air. This condition makes it necessary to pay
a great amount of attention to all of the unpainted metal surfaces.

235. Difficulties Involved in Service. — The winch that was
supplied on the mount as originally designed is not powerful enough
to move the mount along the track. It will be necessary to provide
a more powerful winch for the operation of the mount at elevations
under 15 degrees. The trunnion bed plate casting is very heavy,
and difficulties were encoimtered in installing the emplacement with
the special crane that was provided. It is probable that the casting
is heavier than it need be, and it is likewise probable that the crane
provided was not as powerful as it should be. The type of emplace.
ment required for the operation of this gun at high elevation has
always been considered objectionable because of the excessive time
required for its installation. The platforms used by the French
gims required from two to five days for installation and usually two
days for removal. This platform can be installed a little more quick-
ly, but from two to three days is a fair average. The use of this type
of emplacement, of course, requires a special crane car or locomotive
crane and the total battery equipment is unusually large.

236. Merits. — In speaking of this carriage from the broadest stand-
point it can not be said to have many merits. It can be fired without
any track preparation up to an angle of 15 degrees, but it would be
criminal to fire a gun of this type at any such angle except in an ex-

332

treme emergency. The loading mechanism is excellent in that it is
simple and is operated entirely by hand.

237. Demerits. — ^It should be understood in dealing with this car-
riage that it is a carriage produced purely for the emergency and may
be classed with what the French call "Aflfuts de Circonstance."
When fired at an angle, above 15 degrees it re<)uires the same cum-
bersome firing platform that is used with the BYench 340-millimeter
gun and 400-millimeter howitzer. The carriage is supported on two
six-axle trucks, and the axle load on the front truck is so great as to
cause considerable trouble with overheated journals and bearings.
Considerable difficulty was experienced in securing permission to move
this mount over French railways because the axle loads of the front
truck exceeded by 13,000 pounds the permissible axle load for
French railways. It seems quite certain that nothing but the des-
perate need for guns for this range and caliber could have secured

• * -

the necessary permission to move them about. The axle load on the
front truck is approximately 53,000 pounds. The maximum permis-
sible axle load on French railways is approximately 39,000 pounds.
It is understood that an axle load of 62,000 pounds is permissible on
main lines in America. It seems quite certain, however, that serious
difficulty would be experienced in moving these mounts over newly
constructed lines laid over areas that had been badly shell torn. For-
tunately it was not necessary to move the mounts on any lines except
those that were on fairly settled ground.

238. In moving the five carriages of this type, which were operated
by Navy personnel, from St. Nazaire to Camp Mailly, all of them but
one developed serious difficulty with overheated journals, and the one
that escaped this difficulty was run at an average speed of 5 miles
an hour. In retiu-ning one of the mounts from Camp Mailly to Bor-
deaux for return to America, it was necessary to put it in the French
shops three times to repair damages to overheated joiu-nals and bear-
ings. It would seem possible to limit this difficulty by providing
all of the bearings with hard greas,e cellars such as are used on large
locomotives. This would provide a positive oiling system that prob-
ably would make it possible to operate the mounts already con-
structed with less difficulty. The armor-plate cab is probably more
of a nuisance than an advantage. While the mounts were being op-
erated against the railway yards of Montmedy and Longuyon from
the vicinity of Verdun, the Germans located the battery positions.
Some shells biu^t very close to the mounts. One of these bm^ts
would have resulted in a number of casualties had the mount not been
equipped with armor. This is one of the few cases on record in which
the enemy were able to locate the railway positions accurately and
fire on them with any effect. None of the heavy gun mounts in the
French and British Armies were provided with any such armor and

333

apparently they never felt the need for them. As noted before, this
steel cab gave considerable di£Glculty from the condensation of mois-
ture on all metal siuf aces within it, and it is felt that the chance case in
which the enemy was able to locate the position does not warrant the
providing of armor. The Italian 38-centimeter railway mount has an
armor-plate roof over the working platform to protect the personnel
from machine gun fire from air planes. The German 28, 24, and 21
centimeter guns were likewise provided with light armor, but it is felt
that excessive use of heavy shelters, concrete as well as steel, by the
Germans indicates rather a tendency toward proved needless and
foolish precautions and should not be considered an example that

is to be followed.

Plate 252

14 IN. NAVY RAILWAY MOUNT -MARK I

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11.— AMEBICAN 14-INCH GUN ON NAVY RAILWAY MOUNT, MARK H. (24)

239. This mount is of the combined cradle and rolling recoil type.
The gun is mounted in a criidle having a combined hydrospring and
pneumatic recoil mechanism. This cradle is mounted in a heavy cast-
steel slide which is carried in guides attached to the side girders.
This slide is capable of moving upward at an angle of 45 d^rees with
the vertical, through a distance of 86 inches above ihe traveling posi-
tion. The structwal steel girder is supported at each end by a span
bolster on two five-axle trucks. Neither the car body nor the gun is
provided with any traverse, and it is necessary to operate the mount
on a curved track. When the gun is fired, the entire mount rolls
back on the track a distance of from 30 to 40 feet. General views are
shown on plates 279, 280, 281, and 282.

240. GtTN. — ^The gun for which this mount was primarily designed
is identical with that used on the railway mount, Mark I — that is, a
14-inch naval rifle, Mark IV, Modification I, of 50-caliber length. It
is possible, however, to mount a 9-inch gun with its cradle in the same
slide.

241. Recoil Mechanism. — ^The recoil mechanism proper is in
every respect identical with that of the 14-inch gun used on the rail-
way mount Mark I, plate 34. The difference in respect to recoil,
between the Mark II and Mark I moimts, is that on the Mark II
moimt the gun can be fired without any track preparation whatever
to its maximum elevation of 40 degrees, while on the Mark I mount
it is possible to fire the gun. to an elevation of only 15 degrees with-
out track preparation. The maximum recoil of the 14-inch gun is
44 inches when the gun is operated at the maximum elevation of 40
degrees. The recoil of the 9-inch gims at 43 degrees is 36 inches.
The air for recuperator cylinder is supplied from the air pump in-
stalled on the front span bolster, plate 279.

242. Elevating Mechanism. — ^The elevating mechanism in its
essential details is identical with that of the Mark I mount, shown on
plates 268 and 269. The only difference is in the connections between
the handwheels and cross shafts which drive the miter gears in the
gear case. This modified connection is shown on plate 284 in the
central figure. It will be observed here that handwheels are mounted
directly on shafts which carry pinions on the inner ends meshing with
spur gears carried directly on the cross shafts.

243. Traversing Mechanism. — ^It has already been mentioned
that this carriage is not provided with any internal traversing mechan-
ism. It is necessary to operate it on a curved track to train the gun
in azimuth.

244. Gun Carriage. — ^The cast-steel slide in which the gim and
its cradle are carried will be described under this head. One of the

359

qualifications desired of heavy railway mounts during the present
war was a practicable means of rapidly installing an emplacement or
otherwise preparing for action. With most heavy gun carriages it
was necessary to provide some design of ground platform for operating
the gun at high elevations. This provision of a heavy ground plat-
form was necessitated by two considerations. When operating the
gun at high elevations, the vertical component of the shock of recoil
is ordinarily greater than can safely be transmitted through any
except extremely heavy trucks. The second consideration is that
if the gun is to be operated at its maximum elevation without the
use of a subtrack platform and pit under the center of the gun, it is
necessary either to place the trunnions very close to the breech of the
gim or elevate the trunnions above the track by some method in
order that the breech of the gun may not strike the ties at full recoil.

245. It was understood, of course, that any gun mount operating with-
out a subtrack platform would have to be either of the sliding or roll-
ing recoil type. On the Armstrong 14-inch mount this problem was
solved by mounting the gun in a cradle, whose trunnions are close to
the breech of the gun, and by connecting the rear end of the cradle
with the piston of a large air cylinder by means of. two connecting
rods, in order that the extreme muzzle preponderance of the gun
might be counterbalanced. On the new French 340-millimeter gun
carriage the French designers solve this problem by providing two
sets of trunnion bearings. The low trunnion bearings are to be used
for transportation of the gun which will be transferred to the high
trunnion bearings for firing. In the design made for the Army
16-inch gim early in 1918, it was proposed to raise the center line of
the trunnions of the gun by means of a slide somewhat similar to
this, but sliding in vertical instead of inclined guides.

246. The slide of the 14-inch Mark II mount is shown at its lowest
position on plate 280 and at its highest position on plate 281 . On plate
283 it is shown in detail with the niechanism used in elevating it.
Two 9-inch pistons connected to the slide enter hydraulic cylinders
attached to the body of the car. By means of these hydraulic
cylinders it is possible to move the slide in the direction of the guides
through a distance of 86.28- inches, thereby elevating the center line
of the trunnions 61 inches. When at either its upper or lower position
the slide is pinned to the carriage by means of two 10-inch pins
which are entered or withdrawn by a screw operated by ratchet levers
on the outside of the mount, plate 281. These pins, together with the
slides and the hydraulic jack, carry the weight of the gun and cradle
in transit and transmit the force of recoil into the carriage in firing.
The same type of antifriction mechanism that is used on the Mark I
mount is incorporated in this design. This is shown on plate 283.

360

247. Car Body. — ^The car body consists of two heavy single web
structural steel girders connected by structural steel transoms. One
noticeable difference between this car body and that of the Mark I
mount is the absence of armor. All equipment on the top of the
carriage, hand rail, hand rail standards, and ammunition trolley,
plate 280, is removable for traveling.

248. Anchorage. — This is a rolling recoil type of mount and
the only means of anchoring it is the friction of the brakes oper-
ated by hand. On firing, the entire mount rolls back on the track, a
distance of from 30 to 40 feet. On the front span bolster, plate
280, is mounted a motor-driven winch carrying a cable which is
attached to the track some distance ahead, and by means of which
the mount is returned to its firing position.

249. Trucks. — ^The trucks are ten-wheel locomotive type with 6 by
12-inch journals and 36-inch wheels. As noted before, there are four
trucks connected in pairs by structural steel span bolsters. The
brakes provided on all trucks can be operated by hand as well as
by air. Auxiliary air tanks are charged from the pump mounted just
behind the winch on the front span bolster.

250. Ammunition Supply System. — On the rear span bolster is
mounted a track carrying a steel tray. Both track and tray are
practically identical in design with the track and tray provided on
Mark I mount and shown on plate 276 . When the shell tray is at the
forward end of the track, plate 279, the shell is picked up by tongs
suspended from the I-beam trolley, shown on plate 280. By means
of this trolley the projectile is carried forward and placed on the
tray suspended between the stand on the superplatform and the breech
of the gun. The gun is loaded at an angle of minus 5 degrees. The
loading tray is shown in position on plate 279 ; it is kept in the alter-
nate position shown when the gun is being fired. A structural steel
jib crane is likewise provided on the side of the mount, plate 279, to
pick up ammunition from the ground or from another car in the
event that it is not practicable to take the ammunition out of the car
directly at the rear of the mount.

251. Maintenance. — These mounts have not seen anv field service
and it can not be estimated with certainty-just what the extent of the
maintenance will be. They are very sturdy in construction and it
does not seem probable that they will require Excessive service in
maintenance. The loads on the axle are such as to avoid the over-
heating that gave so much trouble on the Mark I mount. The con-
struction of the slide is simple and sturdy and it is not probable that
it will give any trouble.

252. Difficulties Involved in Service. — ^Thc only difficulty
that will be involved in the service, if it may really be termed a dif-

361

ficulty, will be the construction of the heavy firing positions or epis
that are required for training the gun in azimuth. These firing
positions are always very well prepared and require an unusual
amount of ballast, extra beavy ties and rails, and considerable main-
tenance while the guns are being operated. The labor required in
constructing these epis can not be considered a cause for complaint,
because it is ordinarily difficult to keep the personnel of such a bat-
tery comfortably busy. The time required for the construction of such
epis, however, frequently is a cause for complaint. The time re-
quired to lay a new firing track and prepare it for action may vary
from two to three days.

253. Merits. — The merit of the carriage is that it can be fired
at the maximum elevation without the installation of firing plat-
forms, which are difficult to install or transport. As just men-
tioned, occasionally the time required for the installation of a firing
track may be a cause for complaint. This is not ordinarily true,
however, since the targets on which such guns operate in land war-
fare, are fixed, and some leisure is available in preparing for action.
They are practically self-contained, in that they require no auxil-
iary equipment for their service. The mount as it is seen on plate
280, practically in traveling order, can be made ready for action in
less than an hour, as shown on plate 282.

254. Demerits. — This mount was designed during the active
period of the war and was so designed as to be capable of construction
in a minimum of time with t-he manufacturing facilities available.
No internal traversing mechanism for fine adjustment of the gun in
azimuth has been provided. Such a mechanism is desirable and if
more time had been available it is probable that it would have been
provided. When considering large gun railway mounts from the
standpoint of their use for coast defense, as well as for land warfare
it is not certain that this is a desirable type. It is probable that a
rolling recoil type of carriage can be operated successfully against
a moving target, but it has not been satisfactorily proved. For
such a valuable gun it seems now that its carriage should be so
designed as to be fitted not only for field service, as this carriage is
fitted, but likewise so designed as to be capable of installation on some
type of rotable platform in order that it may be easily and accurately
traversed and efficiently operated against moving targets.

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12.— AMERICAN 14-INCH GUN ON SUDING TYPE RAILWAY MOUNT,

MODEL OF 1918. (25)

255. This is a mount of the sliding type. The gun is supported
by means of its trunnions directly in bearings attached rigidly to
the side girders of the car body. The gun and mount slide back
together along the track in recoil exactly as the 10-inch and 1 2-inch
sliding mounts. General views are given on plates 286, 287, 288,
and 289. This is one of the two designs made up in France in
August, September, and October, 1918, by a combined force of
French and American engineers. The French Government had
arranged to purchase forty-five 14-inch, 50-caliber guns from the
United States; hence the decision on the part of the French and
American technical services to combine on a conmion design of
carriage. No carriages of this design have been manufactured and
it is probable that none will be. The other of the two designs men-
tioned above is the next mount described. The essential difference
between the two mounts is that on the model 1918 it was planned
to use a maximum of structural steel, and on the model 1919 a
maximum of steel castings. This resulted, of course, in radical
differences in the details of design of many mechanisms, as will be
observed in the detailed descriptions.

256. Gun. — ^The gun employed with this mount is the 14-inch
naval rifle, Mark IV, Modification I, of 50-caliber length. It was
to be fitted with a trunnion band screwed and shrunk on, plate 290,
and it was intended to swing the breechblock to the side instead of
down. The breech was likewise to be equipped with a counter-
weight, plate 291, to allow mounting the trunnions as near the
breech end as possible. The breech mechanism has been described
in detail under the 14-inch naval mount, Mark I.

257. Recoil Mechanism. — No recoil mechanism, as it is ordinarily
understood, is used in this mount. When the gun is fired, the shock
of recoil is transmitted by the trunnions directly into the car body
and the entire mount slides back on the track, being stopped by the
friction between the sleepers in the bottom of the car, and the special
firing beams laid on the ties.

258. Elevating Mechanism. — ^The gun can be elevated from 1
degree 30 minutes, the loading angle, to a maximum of 38 degrees,
by a combined hand and electric power operated mechanism, the
design of which is shown on plates 292 and 293. The elevating rack
is bolted to the counterweight on the right-hand side, and as noted
before, the gun can be elevated either by hand power through the
handwheels mounted on the tops of the two side girders, or by means
of the electric motor located some distance forward and between
the girders. The power for operating the elevating motor was to be
supplied from a gasoUne-electric generator that was likewise to be

181768—21 24

368

mounted within the car body. This same generator was to furnish
power for elevating the gun and for translating the mount along the
track. To protect the generator from being damaged by excessive
strains in firing, it was intended to mount it on a sliding base equipped
with spring or hydraulic buffers. When operated by hand, one
revolution of the handwheel moves the gun through 0.48 degree in
elevation. The motor is 7i horsepower and is connected with the
worm shaft by means of a chain. A clutch is provided so that the
handwheel does not rotate when the motor is being used. An
antifriction device of the design shown on plate 294, is incorporated
in the mechanism. This type of antifriction device is considered
preferable to that employed on the model E and the naval mount,
Mark I, in that it includes Belleville springs which are comprised
on firing and permit the shock of recoil to be transmitted more
directly through the trunnion bearings. It is the same in design
as the mechanism used on the 12-inch, 50-caliber gun mount, plate
178, and the 16-inch howitzer mount, plate 357. Its action on the
16-inch howitzer mount has proved particularly efficient.

259. Traversing Mechanism. — Wide traverse can be secured
with a mount of this type only by operating it on a curved track.
The one difference between the operation of this mount and the
10-inch mount, under which the operations have been described in
detail, is that the piece is both traversed and returned to the firing
position by electric translating motors mounted in the extreme
forward and rear trucks. This motor driven translating mechanism
is shown on plate 295. The electric current is supplied from the gaso-
line-electric generator mounted in the car body. On this plate, it will
be observed that the electric motor (20 horsepower), drives by means
of a spur gear, a longitudinal shaft, which in turn drives a cross shaft
by means of miter gears. This cross shaft drives by means of two
sets of spur gears, two other cross shafts on the second of which are
mounted three sprocket wheels. Chains connect these three sprocket
wheels with other sprocket wheels on the three nearest axles. A
solenoid operated clutch is provided to throw the motor out of gear
in the event of an excessive overload. This translating mechanism
on each truck can likewise be driven by hand by means of four
handles, two on each side of the truck. Provision is made likewise
for traversing the entire car body on the span bolsters in a manner
similar to that employed on the 14-inch mount, model E. The
details of this mechanism are shown on plates 296 to 302. A traverse
of 2.5 degrees on each side of the center line is secured through the
provision of a traversing table or bolster with a pivot casting rigidly
bolted to it, plate 295, which at the bottom, turns in a center casting
bolted rigidly to the main bolster and at the top, turns in a ceiU-er
casting which has guides machined on two sides, and slides in grooves

369

cut in a casting bolted rigidly to the car body. A nut is machined
in the top of the upper center casting, in which the traversing screw
turns. The ends of this screw are turned down, plain on one end
and with rings at the other, plate 296, and are fitted with bearings
which are a part of the casting bolted rigidly to the car body.
When the car body is exactly on the center it may be locked for
traveling, plate 297. On the extreme ends of the screw, are mounted
sprocket wheels which are operated by chains, sprocket, pinion, and
handwheels mounted on both sides of the car body, plates 298 and
299. The car body rests on the traversing table by means of two
sets of rollers, plate 300, and the traversing table rests on rollers
carried in the main bolster, and of a design shown on plate 302.

260. Gun Carriage. -^The gun carriage is incorporated with the
car body and the two are described together in the next paragraph.

261. Car Body. — ^The car body or main frame consists of two heavy
structural steel box girders connected by deck plates and structural
steel transoms. The design is shown in detail on plates 303 to 308.
The cast-steel trunnion bearings equipped with antifriction devices
are mounted on the tops of the side girders. The 50-kilowatt gaso-
line electric generator set is mounted forward between the girders,
and the sleeper jacks and sleepers are assembled in the bottom of the
girders.

262. Anchorage. — ^The anchorage system is, in general, like that
of the 10-inch and 12-inch mounts and the French sliding mounts.
The bearing stringers on which the mount slides are 10-inch, 40-pound
I beams. Eight lines of these are bolted to the ties on the inside and
outside of the rails. Six sleepers, five under the main body of the
mount and one under the rear span bolster, transfer the weight of the
mount to the stringers and transmit the firing load. Each sleeper is
made up of three heavy timbers bolted together and is supported on
two jacks for vertical movement. The design of the jacks and
sleepers is shown on plates 309 and 310. The sleeper under the rear
span bolster is provided with steel shoes which bear directly on the
rails. It is ordinarily estimated that about half of the weight of the
mount is transferred to these sleepers in preparation for firing.

263. Trucks. — ^The trucks are special five-axle locomotive type
with 6 by 11 inch inside journals and 33-inch cast steel wheels and
structural steel side frames, deck plates, and transoms, plates 311 and
312. Hand and air brakes are installed on the exterior trucks,
plate 313.

264. Ammunition Supply System. — ^Ammunition is transported
from the ammunition car to the mount by means of a shuttle car, or
transbordeur, of the design shown on plates 314 and 315. This
transbordeur carries five full rounds of ammunition. The two ends
of the top of the transbordeur are made up of hinged wings, which

370

are swung around and locked to the main frame in traveling. The
transbordeur is equipped with an ammunition truck, which can be
run forward on the forward wings by means of a hand-translating
mechanism until it is under the jib crane mounted on the rear of the
mount, plate 2S7. The projectile is transferred hj this crane to
another truck on the loading platform. This second truck has a
tray of such length that when the truck is moved to the forward end
of the loading rail and locked in place, the tray projects into the
breech of the gun. The projectile is rammed by hand. Ammunition
cars of the same design as those used with 8-inch guns, plate 106, but
with special fixtures for this size and weight projectile, were to be
used with this mount.

Pura 285

l4M.I?AtLVMY MOUNT- MOOet 1918
TOTAL WEIGHT 616.000 LB&

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13.— AMERICAN 14-INCH GUN ON SUDING-TTPE RAILWAY MOUNT,

MODEL 1919.(26)

265. This is the alternate design that was made up in France in
1918 for 14-inch, 50-caiiber guns. As noted under the description of
the model 1918 design, this mount was so designed as to contain a
maximum of steel castings. The truck frames, span bolsters, sleeper
housings, etc., are all steel castings. The decision to attempt to
make these very large parts in the form of castings was the result of
difficult manufacturing conditions prevailing in America at that time.
It was felt that time could be saved and better results secured from
the use of steel castings than from similar parts made of structural
steel. Circumstances connected with this mount are mentioned in
the deiscription of the model 1918 mount. General views are given
on plates 317 to 320.

266. Gun. — ^The gun employed with this mount is the 14-inch naval
rifle, Mark V, Modification I, of 50-caliber length. It is identical in
all of its details with the gun described under the model 1918 design.

267. Recx)il Mechanism. — ^No recoil mechanism, as it is ordinarily
understood, is used in this mount. When the gun is fired, the shock
of recoil is transmitted by the trunnions directly into the car body
and the entire mount slides back on the track, being stopped by the
friction between the sleepers in the bottom of the car and the special
firing beams laid on the ties.

268. Elevating Mechanism. — ^The elevating mechanism provides
for a movement of the gun from the loading angle, 0 degree to
38 degrees. It consists of a circular rack bolted to the counterweight
on the breech end of the gun, plate 321, a pinion meshing with it and
two spur gears, a slip-friction device, a wormwheel and worm, and
miter gears on a cross-shaft mounting handwheels on each side of the
car body. A chain drive extends from the worm shaft to a 7i-
horsepower electric motor and a clutch is provided so that the hand-
wheel does not rotate when the motor is being used. When operated
by hand, one revolution of the handwheel moves the gun through
20 minutes in elevation. An antifriction device, of the design shown
on plate 322, is provided on the trunnions to reduce the effort required
in elevating and depressing the gun. This design is the same in
principle but differs slightly in its details from that of the model 1918
mount. -

269. Traversing Mechanism. — ^It is necessary to operate this '
moimt on a curved track to secure a wide range of traverse. It is
possible to traverse the car body on span bolsters by a mechanism,
the design of which is shown on plates 323 and 324, and the location
and general arrangement of which is shown on plates 319 and 320.
Through this mechanism it is possible to secure a traverse of 2.5
d^rees on each side of the center line. Attention is invited to the
differences in the details of design between this mechanism and the

402

traversing mechanism for the model 1918 mount. Electric-trans-
lating mechanisms are momited on the two outside trucks and each
consists of a 25-horsepower motor connected through spur and bevel
gears and two sets of reducing gears to a crank shaft on the outer
end of the truck. From the crank pins on this shaft-connecting rods
extend on each side to three of the five axles, plates 326 to 327.

270. Gun Cabriaqe. — ^The gun carriage is incorporated with the
car body and the two are described together in the next paragraph.

271. Car BooT.^The car body consists of two structuralnsteel box
girders connected by heavy deck plates and a series of structural and
cast steel transoms, plates 328, 329, and 330. One of the essential
differences between the design of these girders and the girders of the
1918 model is that provision w*as made for a maximimi of machine
riveting. The 1918 model follows more nearly the French design
and requires considerable hand riveting. Another apparent difference
is in the scheme of bracing the trunnion bearings. The trunnion
bearings on this moimt are braced at the rear by extensions of the
web plates passing through slots in the top cover plates. Special
center-pin castings of large size form the pivots for the span bolsters
at either end.

272. Anchorage. — ^The scheme of anchoring this mount is iden-
tical with that described imder the previous mount and for the 10-
inch and 12-inch mounts as well. Eight lines of 10-inch, 40-pound
I-beam bearing stringers are laid on the ties and the weight of the
mount rests on these through five sleepers. The sleeper under the
rear span bolster receives its main load on the firing of the gun and
prevents excessive stressing of the trucks. To facilitate manufactur-
ing of the girders, the sleepers are carried in castings instead of be-
tween extensions of the web of the side girders, as is the case with the
model 1918 mount. The design of the jack castings, jacks, and sleep-
ers is shown on plates 331 and 332. It will be observed on plate 343
that the rear span bolster sleeper bears directly on the rails through
steel shoes and does not rest on the I-beam stringers.

273. Trucks. — The trucks are special five-axle locomotive type
with 6.5 by 12 inch inside journals, 28-inch cast-steel wheels, and cast-
steel side frames and transoms. Hand and air brakes are installed
on the exterior trucks, plate 333. The car body is supported on these
four trucks by means of cast-steel bolsters of a design shown on plate
334. The traversing mechanism already described is installed in the
span bolsters.

274. Ammunition Supply System. — ^Ammunition is supplied from
the ammunition car to the mount by a shuttle car or transbordeur
identical in design with that described for the model 1918 mount.
The same design of jib crane, shell tray, and track are likewise used.
This gun loads at 0 degree elevation. It will be remembered that
the r lads at plus 1 degree 30 minutes elevation.

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14.— AMERICAN 16-INCH HOWITZER ON RAILWAY MOUNT, MODEL E. (27)

275. The design of this mount was begun in 1915 at about the time
the design for the 4.7-inch howitzer was being completed. In other
mounts already described it has been clear that the design has been
eflFected quite largely by French and British development in this type
of artillery. The designs for the 4,7-inch gun, the 14-inch gun,
model E carriage, and the 16-inch howitzer model E carriage were
all designed before American Ordnance engineers had had the
opportunity to study any European designs or to learn anything about
their developments. It is very gratifying that these designs, espe-
cially the 14-inch model E embody features which were considered
quite admirable and indicated considerable progress by European de-
signers even at the close of the war.

- 276. The design of the 16-inch model E carriage was completed
in September, 1916, and the work of manufacturing was well under-
way before America entered the war. A number of characteristics
in this design point to a lack of comprehension of the possibility of
the railway type of artillery and indicate likewise that the work of
design on railway mounts was at the beginning of its development.
Apparently it was not realized that it was desirable to avoid the neces-
sity for digging a pit 90 inches deep for the gun to recoil in. The
trunnions of the gun cradle, which is the same as the cradle used in
the 1918 carriage, might ^ave been mounted at such a height as to
reduce the depth of the pit to 2 feet. The other characteristic in
mind is the use of so clumsy a device as the radial truck frames for
attaching the traversing rollers to the mount. In spite of these
obvious defects the carriage stands in point of possibilities for both
field and coast service as practically equivalent to the most modem
designs in that its emplacement can be installed in a moderate
length of time; it can be traversed in any direction from any posi-
tion, and the howitzer can bo operated to a maximum elevation of 65
degrees. General views of the howitzer as it arrived from the arsenal
for proving are shown on plates 335 to 339. The general design of
the carriage is shown on plates 340, 341, and 342.

277. Gun. — ^The gun used with this mount is the 16-inch howitzer,
model 1918, Mark I, of 18-caliber length, jt is carried on the mount
in a cradle containing the hydraulic recoil mechanism and spring
recuperator system. The gun is fitted with splines which slide in
spline ways in the cradle to prevent rotation of the gun. it is rifled
with 144 grooves which twist to the right at a pitch increasing from
one turn in 40 calibers to one turn in 20 calibers. It is provided
with an interrupted thread breech block, which is fitted with a
mechanical firing mechanism.

278. Recoil Mechanism. — The recoil mechanism is of the hydro-
spring type and comprises two hydraulic recoil cylinders mounted
at the top and bottom of the cradle in the center, and four spring •
recuperator cylinders, mounted two above and two below. The

423

design of the spring recuperator cylinders, as well as the recoil cylin-
ders, is shown on plate 343. The recoil and recuperator systems of the
two carriages, models E and 1918, are identical. On plate 362, a
by-pass tube can be seen connecting the front end of the buffer with
the rear of the recuperator cylinder. A similar by-pass is provided
on the lower cylinder. These by-passes are provided for the purpose
of adjusting the length of recoil for various weights of projectiles
and powder charges. The maximum length of recoil is 48 inches.

279. Elevating Mechanism. — Elevation is provided from 0 de-
grees, the loading angle, to plus 65 degrees. The mechanism com-
prises two segmental circular worm racks attached to the sides of the
cradle, Hindley worms, miter gears and bevel gears leading to the
cross shaft mounting handwheels on either side of the car. The
design of this mechanism is shown on plate 344. To reduce the effort
required in elevating and depressing the gun, the trunnions of the
cradle are provided with antifriction devices of the rolling wedge or
knife-edge type, plate 345. This same design of antifriction device
has been used on the 14-inch gun carriage, model E and the two 14-
inch naval carriages Marks I and )I. One turn of the handwheol
moves the gun through 1 degree in elevation.

280. Traversing Mechanism. — ^The gun and cradle are fixed
with respect to the car body and it is necessary to rotate the entire
mount to train the gun in azimuth. The gun and carriage rest by
means of 16 rollers carried in radial truck frames, plate 346, on curved
railway rails attached to the base ring, plate 341. On either side of
the mount, plate 342, identical traversing mechanisms rest on the
curved rails of the base ring by means of four rollers and are attached
to the mount by means of tie-rods. In each of these a vertical shaft
carrying a pinion at its lower end meshing with the traversing rack
is driven by two handles through bevel gears. As the mechanism was
originally designed, one turn of the crank traversed the gun through
5.75 degrees. This ratio was so high as tomakeit practically impossible
for four men to traverse the mount. The mechanism has been modified
and the ratio is now one turn of the handwheel to 0.5 degree in azimuth-

281. Gun Carriage. — The gun carriage is incorporated with the
car body and will be described in the next paragraph.

282. Car Body. — The gun with its cradle is supported directly
by means of the cradle trunnions in cast-steel bearings bolted to the
inside of the side girders of the car. The car body is made up of two
single web structural steel girders connected, by cast-steel transoms at
the ends, and by a cast-steel yoke in the center, plate 347. The cast-
steel transoms at the ends serve likewise as body bolsters and carry
the body center plate which rests in the center plate of the truck.
Examination of the top view, on plate 345, gives one the impression
that the girders are not sufficiently braced with transoms and deck
plates. It is probable that some weaving of the side girders will be
experienced in traveling and consequent difficulty in the operating

424

of the elevating mechanism, similar to that experienced in the 12-
inch, 50-caliber, mount may be the result.

283. Anchorage. — The scheme of emplacing the mount is shown
on plates 348, 349, and 341. A conical pit 90 inches deep by 192
inches in diameter at the top and 70 inches in diameter at the bottom
must be dug to receive the gun in recoil. A circular trench must
likewise be prepared about this pit to receive the base ring. The base
ring is cast steel and is made in four parts, plates 350 and 351. This
base ring may be carried in four parts in an ordinary flat car or in
halves in a special flat car, as shown on plate 348. Seats are machined
on top of the base ring for two complete circles of standard 80-pound
rails. On the inside of each of the quarter sections are two lugs, the
one which serves as an attachment for the lifting beam and the other
supports one of the I-beam stringers which carry the service rails
used in placing the mount on the emplacement. Timber supports
are placed in the conical pit and two I-beam stringers carrjring rail-
waj' rails are placed across the pit, resting on the lugs just mentioned
and on the timber support on the center. The traversing rack of
each quarter section, plate 350, is cut in order that short sections of
rail may be laid across the ring. Small sections of traversing rack
are bolted into these openings to complete the rack when the mount
has been set in place.

284. Four radial truck frames of a design shown on plate 346, two
with inclined top surfaces and two with horizontal top siirfaces and
each containing four rollers, are placed on the base ring on either side
of the mount. Key plates are provided on the inclined surfaces of the
lower cords of the side girders forward of the center to receive the
forward truck frames. The mount is raised about an inch by means
of four hydraulic jacks under the ends of two H beams placed between
the car body and the trucks as far forward and back as possible and
the trucks removed. The radial trucks are then run under, the,
mount lowered and bolted to them. Cast-steel transoms connect the
radial trucks in pairs and outside clips on the trucks engage with the
outside of the traversing rack to prevent overturning of the mount in
firing, plate 341. The traversing trucks, which have been placed on
the base ring by means of the crane, are now connected to the mount
by means of tie-rods. The base ring is placed on well-tamped earth
or preferably on a bed of good rock ballast. A minimum of 1 J days
is probably required for the preparation of the pit and the placing
of the mount ready for firing.

285. Trucks. — The trucks are two in number and of standard M. C. B.
design. Each has three axles with 6 by 11 inch journals and 28-inch
wheels. The trucks are equipped with both hand and air brakes.

286. AMMUNmoN Supply System. — ^On the rear of the mount a
structural steel frame has been constructed to carry the I-beam track
for the ammunition trolley, plates 336 and 340. This I-beam track
can be slid to the rear so that it overhangs the track for a considerable

425

length and the projectile can be picked up either from the track or
from a flat car at the rear. No special scheme has been worked out
for placing the ammimition at the rear of the* mount, but it is as-
sumed that it would be supplied in the standard 8-:inch type of ammu-
nition car, plate 106, with special fixtures for 16-inch projectiles,
and that it would probably be placed from this ammunition car on
a narrow-gauge truck running to the rear of the mount. A special
tray has been provided, plate 341, by means of which the projectiles
can be carried to the breech of the gun and rammed from it. The
powder charge is conveyed to the gun in the same manner.

287. Maintenance.— rit is not anticipated that any difficulties
would be experienced in the maintenance of this mount. All of its
parts are certainly sufficiently sturdy to stand the service for which
it was intended. If any difficulty will be experienced it will be" in
the service rather than in the maintenance of the mount.

288. Difficulties Involved in Service. — ^The necessity for pre-
paring so deep a pit to receive the gun in lecoil can be classed as a
difficulty involved in service of a railway mount. In the event that
it is not found possible to operate with the base ring on tamped earth
or ballast it becomes necessary to use concrete. This will also be
classed as a difficulty in service, because in the European war it was
foimd exceedingly difficult to secure a supply of cement for such uses
on the front. It has not been determined whether the noticeable
lack of bracing between the side girders will result in difficulties in
the operation of the elevating mechanism. This is entirely possi-
ble, since the 'construction is somewhat similar to that of the 12-inch,
50-caliber gun mount on which serious difficulties have been expe-
rienced with the elevating mechanism.

289. Merits. — ^The possibilities of operating this mount at an
elevation as great as 65 degrees and in any direction from any po-
sition on the emplacement may be classed as merits. It will be
remembered that the necessity for constructing a long curved track
to secure sufficient traverse of the gim has been classed as a difficulty
involved in service. Such an emplacement as this can be concealed
perfectly while the curved track can not. The ammunition supply
system may likewise be considered satisfactory in that it is quite sim-
ple in design and operates entirely by hand without any difficulty.

290. Demerits. — The necessity for having a pit as deep as 90
inches, when this might have been avoided, is a demerit. The clumsy
traversing mechanism is likewise a demerit. This mechanism in-
volves the use of four extremely heavy radial truck frames which
are separate pieces of equipment in transit and require a heavy crane
for thfeir installation. The elevating mechanism includes Hindley
worms which it is felt wiU give serious difficulty in field service.

. This type of mechanism is not efficient in comparison with
mechanism composed entirely of spur gears, and when compared
with the mechanism used on the alternate 16-jacJi howitzer carriage.

426

it is not a commendable design. In the near future the necessity
for providing so elaborate a piece of accessorv' equipment as a 120-
ton locomotive crane for the installation of a base ring may be con-
sidered a serious demerit, although tliis is not certain. At present
one has the choice of using a timber firing platform giving a limited
traverse and installed by a Gantry crane of light construction, a
curved firing track which can not be concealed from air photographs
and reqipres at least two days for its installation, or a steel base
ring which can be installed in about 12 hours and which requires a
locomotive crane of lOO-tons capacity or more. Since a locomotive
crane will in general be included with the equipment of railway
artillery parks the necessity for its use on the front may not be a
reasonable criticbm,

Plate 335

IfcHHOWITZER ff/UUVAY MQUHT-MOOCLt"
TOTAL WEIOfT B4&000 LBS.

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443

15.— AMERICAN 16-INCH HOWITZER ON RAILWAY MOUNT, MODEL OF

1918, MARK L (28)

291. This carriage was designed as an alternate mounting for the
16-inch howitzer, model of 1918, Mark I. The howitzer was origi-
nally designed in connection with the 16-inch howitzer carriage,
*' model E,'' already described. This mount is of the cradle recoil
mechanism type, model 1918, or combined cradle and rolling recoil
type, model of 1918, Mark I, in each case with limited traverse.
The design is, in general, similar to that of the French 400-millimeter
howitzer carriage, plate 25, and the design of its emplacement is like-
wise similar to that of the 400-millimeter howitzer emplacement.
Before the carriage was completed the principle of rolling recoil was
receiving considerable attention and a number of trials were made
with this carriage operating as a rolling recoil carriage. It functioned
very satisfactorily, but it was found that it would be necessary to
replace the original five-axle trucks with a stronger type of truck
having six axles. The mount can now be used either on the emplace-
ment originally designed in connection with it, or it can be operated
as a rolling recoil mount. The maximum elevation obtainable on
the emplacement is 65 degrees and the maximum elevation when
used as a rolling recoil mount is 45 degrees. The top carriage has a
traverse of 5 degrees on either side of the center, which is of course
the maximum traverse that can be secured when the mount is used on
an emplacement. When it is being used as a rolling recoil mount, any
desired amount of traverse can be secured by operating it on a
curved firing track. General views are given on plates 353 to 361
and 35.

292. Gun. — The gun used with this mount is the 16-inch howitzer,
model 1918, Mark I, of 18-caliber length. It is carried on the mount
in a cradle which is provided with hydraulic recoil mechanisni and
spring recuperator system. The gun is fitted with splines which
slide in spline ways in the cradle to prevent rotation of the gun. It is
rifled with 144 grooves, which twist to the right at a pitch increasing
from one turn in 40 calibers to one turn in 20 calibers. It is pro-
vided with an interrupted thread breechblock, which is fitted with a
mechanical firing mechanism.

293. Recoil Mechanism. — The recoil mechanism is of the hydro-
spring type and comprises two hydraulic recoil cylinders mounted at
the top and bottom of the cradle in the center, and four spring recu-
perator cylinders mounted two above and two below. The design of
the recoil cylinders is shown on plate 35 and the design of the spring
recuperator cylinders, as well as the recoil cylinders, on plate 343,
of the model E howitzer carriage. The recoil and recuperator sys-
tems of the two carriages are identical. On plate 362 a by-pass tube
can be seen connecting the front end of the buffer with the rear of

AAA

the recoil cylinder. A similar by-pass is provided on the lower
cylinder. .These by-passes are provided for the purpose of adjusting
the length of recoil for various weights of projectiles and powder
charges. The maximum length of recoil is 48 inches.

294. Elevating Mechanism. — Elevation is provided from minus
8 degrees, the loading angle, to plus 65 degrees. The mechanism
comprises a segmental circular rack attached to one side of the cradle,
a pinion, and a train of four spur gears leading to the operating hand-
wheel. A band brake is provided on the handwheel to prevent undue
stressing of the elevating mechanism from the reaction of firing.
This band brake is substituted for the slip friction device ordinarily
incorporated in the worm wheel of a worm-gear transmission. One
turn of the handwheel moves the gun through 1.8 degrees in elevation.
The effort required to elevate and depress the gun is reduced by anti-
friction devices installed on the trunnions and of a design shown on
plate 356. This device has proved particularly eflBcient and makes
it possible to operate the elevating mechanism with very small effort.
The details of design of the elevating mechanism proper are shown on
plate 357. This is the first design completed on which the elevating
mechanism is composed entirely of spur gears. It has proved so
much more efficient than other mechanisms which include the worm
gears that practically all designs made up since this carriage was
completed have been provided with similar types of elevating mech-
anisms.

295. Traversing Mechanism. — The gun can be traversed with
respect to the car body 5 degrees on each side of the center through
rotation of the top carriage about its pintle, by means of a mechanism
whose design is shown on plate 358. The rear of the top carriage
rests on the car body by means of two Belleville spring-supported
rollers, and the carriage is rotated about its pintle, plate 335, by
turning the vertical shaft which carries on its lower end a pinion
meshing with the traversing rack. This shaft is operated by a long
ratchet handle. The uppjsr end of the vertical shaft can be seen just
in front of the ammunition table on plate 256. The upper end is held
in a bearing which is attached to the table. One rotation of the lever
traverses the carriage 4.14 degrees in azimuth. When the mount is
operated as a rolling mount any desired extent of traverse can be
secured through the use of a curved firing track. Under such cir-
cumstances only fine adjustments in azimuth are made by means of
the top carriage traversing mechanism. It is probable that a very
great displacement of the track would result from the operation
of the mount with the gun at either of its extreme positions. The
personnel operating British 12-inch railway mounts having a
maximum traverse of 1 degree on each side of the center reported
slight difficulty in the displacement of their track when the gun was
operated at even the extreme position of 1 degree traverse.

445

296. Gun Carriage. — The gun carriage, plates 256 and 53, com-
prises the cradle carrying the recoil mechanism, and the elevating and
traversing mechanisms already described, all mounted, or carried
on a structure of cast-steel side frames and transoms. The carriage
is provided with a heavy pintle at its forward end, which fits into a
bearing machined in a cast-steel transom of the car body. The r^ar
of the carriage rests on the car body by means of spring-supported
Tollers already described under Traversing mechanism. A structural-
steel working platform carrying the ammunition table and crane is
bolted to the rear of the cast-steel top carriage. Between the cradle
trunnions and side frames antifriction devices already described
under elevating mechanism are incorporated to reduce the effort
required to elevate and depress the gun.

297. Car Body. — The car body, plates 35 and 53, is made up
of two single web structural steel side girders connected by structural
and cast steel transoms. Toward the forward end a cast steel tran-
som, machined at its center to serve as a bearing for the pintle
of the top carriage, is bolted to the side girders. Center plates and
side bearings are provided at either end of the car through which it
is supported on two trucks. Outrigger struts, jack supports and ties
are attached to the lower cord of the side girders for use in anchoring
the mount to its emplacement.

298. Anchorage. — When the mount was designed it was intended
to operate it on a timber platform of the design shown on plate
53. The platform is in two principal parts. The one comprises a
horizontal bed of timbers on which the mount rests through four
jack screws and which takes the dead-weight of the car and vertical
component of the shock of recoil. The other is composed of two
triangular braces resting against a timber pad. These braces are
connected with the mount by means of ball end struts hinged to the
mount and resting in foot plates on the ends of the braces, plate 359.
This part of the platform takes the horizontal component of the shock
of recoil. When the gun is being operated above elevations of 45
degrees, it is necessary to have a pit about 2 feet deep between the
two heavy horizontal timber beds, into which the gun may recoil.
The rails which bridge this pit and on which the mount is run, are
carried on I-beam stringers, plate 53. They are removed for firing-
The time required for the installation of platforms for similar French
340 millimeter gun and 400 millimeter howitzer carriages, varies be-
tween two and five days according to the nature of the ground and
weather. When the gun is fired at angles of 45 degrees or less, the
mount may be operated on a track of heavy construction without the
use of any firing platform. The brakes are set at a pressure to barely
permit rolling of the wheels and the entire mount rolls back a dis-
tance of from 30 to 40 feet. To secure any large degree of traverse

446

it must be operated on a curved track. The mount is drawn back
^to its firing position by means of a winch mounted on the front truck.
This winch is connected with the track some distance ahead by-
means of a cable.

299. Trucks. — The trucks, two in number, are five axle (model
1918) and six axle (model 1918, Mark I), locomotive type with inside
journals. The body and bolster are made up entirely of structural
steel. The journals are 6.5 inches by 12 inches and the wheals 28
inches in diameter. The axles are equalized throughout, thereby
distributing the lo^d evenly over the entire truck. Each truck is
equipped with both hand and air brakes. French type couplers
and buffers were provided during the active period of the war, but
have since been replaced by the standard M. C. B. type.

300. AMMUNmoN Supply System. — ^The ammunition car used
with this mount is identical in design with that employed with the
8-inch railway mounts, plate 106, with special racks of course, to
hold the 16-inch projectiles and powder cans. No special provision
has yet been worked out for transferring the ammunition from the
ammunition car to the mount. A crane is provided on the rear of the

' mount by means of which the ammunition may be lifted from the
ground on either side of the mount, or from a flat car or from the
track at the rear of the mount. After being lifted by means of the
crane the ammunition is placed on a tipping tray on the top of the
loading stand located on the working platform. When the rear of
this tray is tipped up, the projectile slides forward with slight assist-
ance along the removable tray into the breech of the gun and seats
itself. The loading angle is minus 8 degrees. This loading appa-
ratus is shc)wn on plate 53.

301. Maintenance. — Every mechanism of this mount has func-
tioned very well on proof tests and no serious difficulty in the nature
of maintenance is anticipated. There is one possibility of trouble
which may be mentioned under this head. When firing with full
charges and at 45 degrees elevation from the emplacement a slight
lifting of the mount from the bed at the forward end, and a bending
of the struts under the vertical braces at the rear, was noted on two
occasions. This bending was due to crushing of the wood under
the bearing of the strut and to the fact that the strut had a reduced
section near the vertical brace. It is probable that the substitution
of another strut with large section and strengthening of the wood
beam along the top of the triangular braces will eliminate any future
trouble of this character.

' 302. Difficulties Involved in the Service. — The only difficulty
involved in the service with a piece of this type that need receive con-
sideration is the time and care required in the preparation of the
emplacement. This has already been discussed at some length under

447

the 14-inch naval mount, Mark I. It is essential either that the
emplacement be made in firm soil or that a sufficient bed of cinders,
gravel or stone be put under it to insure it against undue settling.
It has been mentioned that the mount can be operated as a rolling
recoil mount to a maximum elevation of 45 degrees. Since it is
probable that for the majority of targets a new track would have to be
installed to give the proper direction in azimuth, the difficulty in-
volved in the laying of this track must be considered. Such a firing
track must be well constructed and be made up entirely of very
heavy components. The firing so far conducted from this mount
indicates that a track similar in construction to that employed in
heavy commercial service will be satisfactory. The deduction is,
then, that the only point in this connection that can be raised is the
increase in time required (two days) for placing a special curved
track, over that required for another mount carrying a gun of similar
caliber, but using an emplacement, possibly of the type employed
with the 14-inch model E mount, which can be installed in about 12
hours. No ammunition-handling system has as yet been carefully
worked out, but it is not felt that any particular difficulties will be
encountered in finding a satisfactory solution.

303. MERrrs. — This mount has an elevating mechanism of excel-
lent design. As mentioned before, this was the first mount com-
pleted on which the elevating mechanism was composed entirely of
spin* gears. Tests have proved its excellence. The antifriction
device has proved equally excellent and the design has been followed
on other mounts.

304. Demerits. — ^The necessity for the use of so cumbersome an
emplacement for the operation of the howitzer at high elevation is a
serioiis demerit. What has been said in this respect under the
14-inch naval mount, Mark I, applies equally here. The limiting of
the maximum elevation to 45 degrees when the mount is used as a
rolling recoil mount is unfortunate. This point is mentioned here,
however, only in comparing the mount with the ideal type of mount,
for it was originally intended to operate it from the emplacement
only; the possibility of operating this particular mount at so great
an elevation as 45 degrees without the use of an emplacement is dis-
tinctly favorable. It seems certain now that a carriage can be de-
signed on which the gun can be operated to an elevation as great as
65 degrees with the mount operating either as a combined sliding and
cradle recoil mount or as a fixed emplacement mount, the emplace-
ment involving no more elaborate components than those employed
with the 8-inch gun and 12-inch mortar.

181768—21 29

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458

16.— AMERICAN 16-INCH GUN ON RAILWAY MOUNT. (29)

305. The description that follows is of what represents perhaps a
study rather than an actual design of a railway carriage for the
16-inch 50-caliber American Army gun. It was made up during tht
early suxnmer of 1918, in anticipation of a need for such equipmene
in FVance, and it is probable that the actual design would have fol-
lowed very closely if not exactly these studies if it had been decided

.to construct such a mount. The mount is of the combined cradle
rolling recoil type and is compoded of a symmetrical structiural steel
girder carrying a unique type of top carriage by which it is possible
to elevate the center line of the trunnions of the gun 40 inches above
the traveling position, and the whole is supported on fom* six-axle
trucks, plate 363. This represents the first known study of a mount
in which provision is made for elevating the trunnions of the gun in
this particular manner. The trunnions are mounted so close to the
breech of the gun as to necessitate a counterbalancing arrangement
to compensate for the considerable muzzle preponderance. It is nec-
essary to operate the mount on a curved track to secure any consid-
erable degree of traverse, but car body traversing mechanisms some-
whatsimilar to those incorporated in the 14-inch carriages, models 1918
and 1919, are incorporated in the front and rear of the mount over
each span bolster. The gun can be fired to a maximum elevation of 40
degrees without any other track preparation than the construction of
a heavily ballasted curved track made of the heaviest rails and ties.

306. Accessory crane equipment, transporting cars, etc., plate 364,
were to be provided for removing the gun and cradle from the mount
and carrying it on a separate transport car. With the very large
cradle that it was necessary to provide for this gun it was impossible
to keep the mount, with die gun and cradle mounted on it, entirely
within the clearance lines of all railwavs in France over which the
mount would probably have had to operate. It would be possible
to transport the mount complete over practically all the main lines
of American railways.

307. The need for such a mount was very carefully considered in
France and it was finally decided that such a unit would not be either
an efficient or economical competitor of the bombing plane. It was
felt that in consideration of the difficulties involved in transporting
such a mount over roads which were not always in the best of condi-
tion, and in consideration likewise of the fact that the accuracy of
fire of such a gun at its maximum range would not be such as to make
it possible to operate effectively against any targets smaller than a
large railway yard or a city, both of which could be operated against
more effectively both as to accuracy in placing the explosive charges
and as to the extent of destruction, by bombing planes, it would not
be wise to divert our limited manufacturing facilities from absolutely
essential ordnance to this experiment.

308. In the autumn of 1918 the Navy Department, on finding
that the avlps nf the 14-inch mount, Mark I, were so heavily loaded

459

as to give continual trouble from overheated journals, designed and
began the construction of a mount whose characteristics were almost
identical with this 1 6-inch mount. This mount, which is termed the
Navy 14-inch Mark II mount, has since been finished. Its total weight
is such as to require only 20 axles as against 24 for the 16-inch mount.

309. Gun. — ^The gun for which this mount was to be designed
is the 16-inch, model E, of 50-caliber length. It is fitted with
splines above and below, which slide in spline ways in the cradle to
prevent rotation of the gun, and a heavy lug or yoke is shrunk on
over the breech, to which lug the four recoil and two recuperator
pistons are attached. The gun is rifled with 144 grooves which twist
to the right at a pitch increasing from one turn in 50 calibers to one
turn in 25 calibers. The breech is of the Welin or stepped thread
type and is equipped with a mechanical firing mechanism.

310. Recoil Mechanism. — The recoil mechanism is of the hydro-
pneumatic type and comprises fom* hydraulic recoil cylinders ar-
ranged symmetrically about the cradle, two above and two below,
and two pneumatic recuperators, placed one in the center at the top
of the cradle and the other in the center at the bottom. The normal
length of recoil is 48 inches and the maximum length of recoil is 49.67
inches. The mount itself is likewise of the rolling recoil type and
while some of the energy of recoil is dissipated in the recoil mech-
anism proper, most of it is absorbed in the friction of the brakes as
the mount rolls back on the track. Most rolling recoil mounts that
have been observed roll back on the track a distance of from 30 to
50 feet. It is assumed that this might represent the probable length
of recoil of this mount also. The design of the recoil cylinders is
practicaUy the same as that of the recoil cylinders of the mounts
already described. The design of the pneumatic recuperators is
practically identical with that of the pneumatic recuperators used
on the 12-inch mortar and the 12-inch BatignoUes mounts.

311. Elevating Mechanism. — Elevation is provided from minus
3.3 degrees, the loading angle, to pliis 40 degrees, the maximum firing
angle. The mechanism comprises two worm racks, worms meshing
with these, and a series of bevel and spur gears leading to the driving
motor and to the handwheels on either side of the mount. The
mechanism is driven by an electric motor under normal conditions,
but provision was made for hand operation in the event that this
should at any time be necessary. Provision is. made likewise for
disengaging the worms from the elevating racks when the gun is in
transporting position. An accessory to this mechanism is the com-
pensating cylinder shown on plate 364, directly below the trunnions.
It was necessary to place the trunnions close to the breech. This
resulted in a large muzzle preponderance, which is compensated for
by the balancing cylinder. This compensating arrangement is an
adaptation of the pneumatic recuperator and consists of a cylinder
placed within a larger cylinder, the inner cylinder sliding in and out
as the gun is depressed or elevated. Tie-rods connect the front of
the inner cylinder with the bottom of the cradle. The stroke of the

460

inner cylinder or piston is 75.52 inches, and the maximum pressure
in the cylinder is 1,950 pounds.

312. Traversing Mechanism. — It is necessary to operate this
mount on a curved track to secure any considerable traverse. Elec-
trically driven translating mechanisms similar in design to those used
on the 14-inch mounts, models 1918 and 1919, are incorporated in
the trucks, for the purpose of training the gun on the curved track.
It is quite probable, however, that the mount would ordinarily be
returned to battery by a locomotive, inasmuch as the length of recoil
of from 30 to 50 feet is so great as to make the time necessary to
return it by means of the translating mechanisms excessive. An
additional mechanism is incorporated in the mount at either end
over the center of the span bolsters. This mechanism is of a design
similar in principle to those mechanisms used on the 14-inch mounts,
models 1918 and 1919, and affords a total traverse of 1.3 degrees.

313. Gun Carriage. — ^The gun carriage comprises a cradle of
gridiron design with its four recoil and two recuperator cylinders and
the cast-steel slide, by means of which the gun can be elevated 40
inches for firing. This slide is composed of two cast-steel side mem-
bers joined by transoms, plate 364, and carries the cradle by means
of trunnions resting in the bearings machined in the top. The car.
riage is raised a distance of 40 inches by means of eight hydraulic
jacks. The pressure necessary in these jacks is approximately 2,100
pounds per square inch. When either at its upper or lower position
the carriage is fixed rigidly to the car body by means of four large
pins inserted through the side girders and the carriage castings.
Additional safety devices are provided at the front and rear of this
carriage on top of the side girders in the shape of screw-operated cast-
steel supports, which can be nm under the extensions of the carriage,
thereby relieving the pins from excessive load. The carriage cast-
ings have four pin holes, the top ones of which are used when the gun
is transported and the lower ones of which are used when the gun is
in battery position. The carriage slides between the webs of the side
girders on fixed grooved guides. The sUdes or supports mentioned
above are provided with stepped surfaces which are intended to
serve as supports when the carriage is being raised.

314. Car Body. — ^THe car body is composed of two single web
structural steel girders joined by a series of structural and cast-steel
transoms and supported at the front and the rear on the trucks by
means of span bolsters. The construction of the girders is sym-
metrical about a vertical center line.

315. Anchorage. — The only anchorage that this mount has in
firing is the friction of the brakes. It rolls back a distance of approxi-
mately 40 feet on the track. The brakes must then be released and
the mount is returned to its firing position by the translating mech-
anism or by a locomotive.

316. Trucks. — The trucks are four iu number, of locomotive type,
and cor' '^ each with 6.5 by 12-inch journals and 33-inch
steel w "des of each truck are equalized throughout so

461

that the load is distributed as perfectly as possible. They are
equipped with semielliptical springs of sufficient capacity to stand
both the transporting and the firing load. The mount is supported
on these trucks in pairs by means of structural steel span bolsters.
The center bearings of these bolsters are of the roller type.

317. Ammunition Supply System. — It is not certain whether the
standard railway artillery ammunition car could have been used
with this moimt. If not, a car of similar design but of heavier con-
struction would have been provided. The loading mechanism is of
a design similar to that provided on the 14-inch mounts, models 1918
and 1919. The loading position of the gun is minus 3.3 degrees/and
the loaded tray acquires sufficient velocity on the inclined track to
cause the projectile to slide into the powder chamber. The projectile
is rammed by hand.

Plate 362

l6ti(S0 CALIBER) 6UN RY MOUNT
TOTAL WEIGHT 85O»00O LBS.

LOADS AT

SSftOOLM-

SS^HfOlSS.

seo'^7'

i€^

ens Ait

£n'54i£i§.ia34^s err

-■srs — —

^

1,-1 . i

Lli.

:r[

m

463

17.— <;}ERMAN 170-MILUMETER GUN, MODEL 1916. ON RAILWAY

MOUNT. (30)

318. This mount is a combination arranged for use as a railway
mount firing from the wheels with small traverse or as an emplace-
ment mount firing from a platform with all-round traverse. It is
made up of a heavy type of mobile gun carriage set on a special drop
frame flat car. The gun carriage is quite similar in design to the
German field carriage mounting 15-centimeter 40-caliber guns and
may be operated from the same type of platform. The mount is
shown on plates 365 to 371 . The car trucks of the mount exammed
bear the date 1917.

319. Gun. — ^The gun is a modem Navy piece, model 1915, of 40
calibers length. It is rifled with 52 grooves twisting to the right at
uniform pitch of 1 centimeter in 10 centimeters. It is provided
with the ordinary type of Krupp sliding wedge breechblock and
uses semifixed ammunition.

320. Recoil Mechanism. — ^The recoil mechanism is of the hydro-
spring type and comprises one hydraulic brake cylinder attached to
the cradle in the center at the bottom and two spring recuperator
cylinders attached to the cradle on either side of the brake cylinder,
plates 366 to 368. The length of recoil is 15 inches. Two round
rods screwed into the recoil lug on either side of the brake piston rod
extend to the rear and carry the yoke which is attached to the two
spring piston rods.

321. Elevating Mechanism. — ^The elevating mechanism com-
prises a rack bolted to the left side of the cradle and a pinion with a
worm wheel, worm and bevel gears leading to a handwheel. Another
handwheel, or rather a crank of 12-inch rs^dius for high speed elevat-
ing, is connected to the first through a sprocket and chain. Sudden
shocks of fire appear to be taken care of by Belleville washers on the
worm shaft, which allow it a slight motion in an axial direction.
This entire mechanism ia disposed along the left side of the carriage
and can be traced out in plate 366. A total elevation of 45 degrees
is indicated on the elevation scale, although a publication at hand
states that 47.5 degrees is possible. The first, 'or adjusting hand-
wheel, gives a ratio of 0.4 degree per turn of handwheel, while the
second at the end of the chain, for rapid movement, gives 1.25 de-
grees per turn. No antifriction trunnions are provided and the
operation of the second handwheel even at slow speed is hard work
for two men.

322. Traversing Mechanism. — ^As noted above, traverse is ob-
tained by moving the field carriage upon the railway car. The car-
riage is kept In place by means of an angle-iron circle fastened to
the flat car floor and around which the wheels of the mount can roll,

181768—21 30

464

plate 236. At the center of this circle is a large pin, fastened to the
car, from which swiveled tension rods extend back to the trail of
the carriage. The gxm carriage wheels bear against the circle of
angles and prevent sidewise movement, whUe the rods prevent
lengthwise movement, but the carriage is free to roll on its own
wheels about the pivot. The two large wheels of the carriage are
about 6 feet in diameter with 19.5 inoh face, of which the center 7.75
inches is raised 2 inches higher than the remainder. These wheels
are made, both rim and spokes, of structural material, generally of
channel section.

323. The rear end of the trail of the carriage body rests, on the car
floor and against a circular rail fastened thereto, plate 368. On the
outside of this rail there is a series of pins, forming a rack, into which
a star wheel fastened to the trail meshes. This star wheel is operated
through a worm, horizontal shaft, and bevel gear, from a handwheel
located near the trunnions on the right-hand flask of the trail. The
weight of the trail during traversing is carried upon two spring-sup-
ported rollers, which give under the shock of fire and allow the trail
to rest directly on the car floor. Twenty-six degrees total traverse
is allowed and the gim is moved 0.167 degree per turn of handwheel.

324. Gun Carriage. — ^The gun carriage is very much like that
provided for the British and American 6-inch mobile guns and, as
noted before, is quite similar to the German carriages mounting 15-
centimeter guns. It comprises a cradle of naval design, plate 366,
and a built-up structural steel body, plates 366 and 368. The cradle
is carried on the body by means of two cast-steel trunnion bearings
without any friction-reducing devices. The cradle is identical in
design with those used on' German ships and in their coast defense*
There is a possibility that this is one of the guns removed from their
second navy late in 1917. The body consists of two built-up struc-
tural flasks of channel sections with flanges 7 inches wide and a
depth of web tapering, as shown on plate 366, from 38 inches in front
to 13.5 inches at the extreme rear. The axle on which the wheels
described under Traversing Mechanism are mounted is bolted to the
bottom of the flasks.

325. Railway Car Body. — ^The railway car is a drop frame flat
car of special and very strong construction. The side sills are built-
up plate girders of very heavy and varying sections, plates 365 and
366. The entire body is decked with about 0.625-inch steel plate.
Except for the very strong construction, there is nothing of special
note about the car body.

326. Anchorage. — For firing at angles up to 13 degrees on each
side of the center line of the track, cast-steel wedges are placed on
the ties under corresponding wedges on the side sills and the mount

465

is moved by a locomotive until it is wedge'd up on these. See plate
366 for wedges under the side sills.

327. For wider traverse and other special service a field platform
and foundation mounted on a special wagon on road wheels are
carried on a flat car, plate 369.

328. The field platform foundation consists of four box girders of
light steel, each about 20 by 35 inches and perhaps 10 feet long. At
one end of each, two 1-inch steel plates are attached to the top and
bottom and extend a foot or so beyond the end, plate 368. A large
hole is formed in these to receive the pivot pin. A rigid equal-legged
cross, which when buried in the ground constitutes the anchorage
or foundation for the field platform, is formed by placing the girders
radially, so that these holes match, inserting the pin, and putting in
place between the girders some special I-beam spacers, plate 371.

329. The field platform, plate 370, consists of a forward member
containing a hole for the pivot pin above mentioned and having
formed at its sides guides for the carriage wheels similar to that
formed by the circle of angles on the car. This is joined by radial
structural members to a large steel plate on which the trail is intended
to rest and which is equipped with a circular arc, inside of which the
end of the trail rotates, and a chain into which the teeth of the star
wheel can engage for traversing. This platform slips down on
top of the foundation above described, and it can be pulled around
into any desired direction for firing the gun. The gun is rolled onto
this platform and the tiebars secured between the trail and the
center pintle just as on the railway car. It can be rotated through a
small angle, perhaps 10 degrees, upon the platform in any position,
and for wider traverse the platform can be moved around any
desired amoimt.

330. Trucks. — ^The trucks are of structural construction, two
axles each, with semielliptic springs and no equalizers. The wheels
are nearly a meter in diameter and have very light spokes. Each
wheel has two brake shoes.

331. Ammunition Supply System. — The shells of this gun are
sufficiently small so that they can be handled by two men with a
tray. The tray employed is provided with eyes, which fasten to
hooks on the breech of the gun. It is hooked in position and the
projectile rammed from it.

332. Maintenance. — The sturdy construction of the car body as
well as of the gun carriage itself, including the cradle and recoil
mechanism, indicates that comparatively no difficulty would be
experienced in maintaining this mount even under the hardest
service and most difficult conditions. The semipermanent emplace-

466

ment is likewise of such sturdy construction that it is not probable
that it would be damaged except with most careless handling.

333. Difficulties Involved in Service. — ^The construction of
this mount indicates that when serving as a railway mount it mi^t
be placed for firing in 10 or 15 minutes. The indications from the
construction of the trucks are that the whole moimt can be rendered
sufficiently stable so that the personnel could remain on the car at
all times and serve the gun with maximum speed, probably one shot
per minute. From the standpoint of efficiency of service this
improvisation certainly seems to fill the bill.

334. Merits. — ^The merits of this improvisation are its sturdy and
simple construction, resulting in a minimum of maintenance, its
exceedingly simple method of emplacement for firing from the rails,
and the excellent and simple scheme of attaching the ammunition
tray to the breech of the gun.

335. Demerits. — If one considers this mount simply from the
standpoint of an improvisation it could not be said to have any
demerits. Under ''Trucks/' it was mentioned that the wheels are
of exceedingly light construction, but the fact that the car body rests
on four wedges when the gun is fired and that when placing the car
on these wedges the mount is likely raised considerably from the
trucks would indicate that there would be no likelihood of breaking
the wheels through shock of fire. From the standpoint of the Ger-
mans it would appear unfortunate that this mount had no greater
traverse than 26 degrees in any one position on the track. It must
be remembered, however, that it was an improvisation, built much
more quickly than any type of all-round fire mount could have been
made, and that probably the limited extent of traverse has been jus-
tified after all.

TRAVKRaiNO GEAR OF THE 170 UM. QBRUAN GUN UODNT.

472

474

18.-<SERMAN 210.MILUMETER GUN ON RAILWAY MOUNT.(31)

336. This mount is of the cradle recoil type, plate 372, firing either
from the wheels with limited traverse or from a structural steel or
reinforced concrete ground platform with all-round fire. It is
similar in general type to the German 240 and 280 millimeter mounts,
and all of them can be operated on the same ground platform.

337. Gun. — ^The gun is a modern naval piece, model 1913, of ^^1
feet total length, probably 45 calibers. The powder chamber :»
only a very little larger than the bore and semifixed ammunition
is used. The tube is rifled with 64 grooves twisting to the right at a
uniform pitch of 1 centimeter in 10 centimeters. The breechblock
is of the ordinary Krupp sliding-wedge type and is fitted with a
mechanical firing mechanism.

338. Recoil Mechanism. — ^The recoil mechanism is of the hydro-
spring type and is composed of two hydraulic recoil cylinders mounted
on the top and bottom of the cradle in the center and four spring
recuperator cylinders moimted two on the top and two on the bottom
of the cradle and on either side of the recoil cylinders, plates 373 and
374. Each recoil cylinder is attached to the cradle by a heavy pin,
about which it can swivel in a vertical plane. The forward ends of
the springs are connected to the recoil b.and by a stirrup and two
tension rods each. The length of recoil is about 24 inches.

339. Elevating Mechanism.— Elevation is provided from 0 de-
gree, the loading angle, to 45 d^rees. The elevating mechanism
comprises two racks with inside teeth bolted to the bottom of the
cradle, two pinions on a common shaft meshing with these, worm
wheel, worm, bevel gears, and a special two-speed gear transmission
leading to a handwheel. The double-speed gear is entirely similar
to that on the 240-niillimet.er mount, shown in detail on plate 381.
The worm and wheel can be seen on plate 375. The ratio of the gear
for slow motion is 0.125 degree of elevation per turn of handwheel;
for fast motion it is 1.50 degrees per turn. A roller-bearing, anti-
friction device is provided on the trunnions, plate 372, which is simi-
lar in every way to that provided on the 280-millimeter mount and
shown in detail on plate 388.

340. Traversing Mechanism. — ^Two traversing mechanisms are
provided on this mount. The one is for the purpose of rotating the
car body about the pintle of the front truck in firing from the track.
It affords a total traverse of 2.25 degrees, or 1.12 degrees on each side
of the center line. The other is for the purpose of rotating the mount
around a center pivot which is fastened to a groimd platform. This
mechanism affords 360 degrees. The first mechanism is entirely
similar to that employed with the 280-millimeter mount and shown
on plates 370 and 391. It comprises a gear case bolted to the side

475

of the mount, a traversing beam housing bolted into the side girders
over the center of the rear truck, and a traversing beam, which is
likewise the upper center plate of the rear truck, sliding in guides in
the housing. The traversing beam is moved with respect to the hous-
ing by a screw, plate 390, which in turn is driven by the handwheel
through the gears in the case on the side of the mount. Since the
beam is fixed with respect to the truck, any motion of the screw
forces the housing and the rear of the mount to the right or left. An
indicator is provided in the top of the gear case to show the extent
of the traverse, and there is a lock for securing the mount in traveling.

341. The second mechanism comprises a center pivot and two
rear support rollers, plate 376. The center pivot comprises a base, 70
inches in diameter, which bolts to the ground platform by twenty
2.5-inch bolts. This base contains a pintle about which the mount
rotates and supports a ball bearing with sixteen 5-inch balls on which
the swiveled racer carrying the mount rests. This pivot is identical
in design with that of the 2S0-millimeter mount, plate 394. The
racer is carried by means of its trunnions in steel bearings bolted to
the bottoms of the side girders. Thus the car body can rock in a
vertical plane as well as rotate in a horizontal plane about the base.
The rear end of the mount is supported on a track in the foundation
by two rollers, 24 inches in diameter by 4 inches on the face, the
housings of which are bolted to the side girders just forward of the
rear truck. These are set on a radius of 14 feet 9 inches from the
center pivot. One of these rollers is provided with gearing, plate 376,
through which it may be driven by one two-man handle. Twenty-
four turns of the handle give one revolution of the roller. This is
equivalent to about 1 degree of traverse per turn of the handle.

342. Gun Carriage. — The gun carriage and car body are one in
this mount and will be jointly discussed in the next paragraph.

343. Railway Car Body. — ^The gun is carried in a cylindrical
cast-steel cradle, about 9 feet long, which is supported in cast-steel
bearings on the side girders of the car body by means of trunnions
about 10 inches in diameter by 7 inches long. The railway car body
consists of two single web plate girders, built up of about 0.625-inch
plate, and 5 by 5 inch angles with cover plates. The, dept^ of these
girders is about 52 inches at the center, 28 inches over the front
trucks, and 34 inches over the rear trucks. Structural steel transoms
are employed throughout and the bracing against skew consists of
a decking of about 0.625-inch plate over the two trucks and against
the underside of the girder. As shown on plate 372, a number of
folding platforms are provided along the sides of the mount, and a cab
of 0.5-inch armor plate is provided around the breech of the gun to
protect the personnel. Special I beams are supported under the

476

front and rear ends of the girder for use in jacking the mount off the
trucks and letting it down on the foundation. The girder rests on
these beams through roUer bearings; adjusting screws are provided
to facilitate exact adjustment of the bolt holes in the pivot flange
with those in the foundation.

344. Anchoilaoe.— This mount must be operated on a curved
track to secure wide traverse when it is fired from the wheels. Special
wedges made in identical halves are bolted to the rails behind each
wheel by one bolt each. These wedges are about 12 inches long by
6 inches high at the rear and are curved to fit the circumference of
the wheel. The ground platform employed to secure all-round fire
is identical in design with that shown on plates 397, 55, and 56.
The mount is run into place on the platform and the small section of
track over the center, as shown in the upper view, plate 397. is re-
moved in order that the pivot base may be lowered on to the struc-
tural base by means of the lowering screw, plate 394. It is bolted
fast by 21 bolts. Four special jacks of a design shown on plate 398,
and attached to .the jacking beams located under the front and rear
of the mount and described in the preceding paragraph, are then let
down and the mount is raised by means of them sufficiently to permit
the trucks to be removed as well as the two sections of track connect-
ing the center with the outside. The entire mount is then lowered
until the rear rests on the circular track by means of the rollers and
the forward end rests on the 16 steel balls in the central pivot.

345. Trucks. — ^The trucks are of structural steel construction
throughout with four axles each, outside journals, semi-elliptical
springs and equalizers between outside axles only, plate 372. A
capstan headed screw is provided over each journal bearing and is
so arranged that it can be screwed down on to the spring clip and
relieve the springs of undue strains when the mount is fired from the
wheels. Hand brakes only are provided.

346. AMMUNITION Supply System. — An overhead trolley runs on
an I-beam track secured along the top of the cab. An extension
beam is so hinged to the fixed beam that it can swing in a vertical
plane, can be lowered for traveling or raised and braced in place
to allow picking up a shell from a car or from the track some distance
behind the mount. The extensible trolley arrangement of the 240-
millimeter mount, plate 378, is identical in design. The shot tray is
provided with two two-man handles, a yoke above with an eye, and
four wheels below, so that it can be carried by the trolley hoist, by
hand, or rolled on the floor. It can be hooked in place on the breech
as with the 17-centimeter mount, plate 373.

347. Maintenance. — ^There are no apparent difficulties in the
maintenance of this design of railway mount, which, as mentioned

477

before, has been used for 24-centiineter guns and howitzers and 28-
centimeter guns. All parts are very simple in design and substan-
tially constructed. The elevating, traversing, and loading mechan-
isms had all seen considerable service and no apparent difficulties had
developed. The trucks had likewise given no difficulty. The speed
transmission introduced in the elevating mechanism of this and the
24-centimeter mount is very sturdy in construction and apparently
did not give any trouble.
. 348. DiPFicuLTiBS Involved in Service. — ^But one difficulty is
apparent in the service of this mount. This difficulty results from
the necessity for using a heavy platform, usually of steel, which likely
requires from three to six days for placing. Without this traversing
mechanism it is, of course, necessary to operate the carriage on a
curved track, making the necessary smaU adjustments in azimuth
by the traversing mechanism on the rear truck. The use of this
steel platform necessitates the providing of a knockdown Gantry
crane, and seven cars are required to carry the crane and platform.

349. Merits. — ^The double speed transmission on the elevating
mechanism is simple in design and very effective. The design of the
traversing mechanism is good. The mount requires either a struc-
tural steel or reeufprced concrete platform, both of which require
some time for instkllation, but in comparison with other mounts now
in existence, this design must be considered good. This is the first
mount on which so simple and effective a type of anti-friction device
has been used and it deserves consideration for our own work of de-
sign. The traversing mechanism installed over the rear truck is
simple in design and excellent for service in .firing from the track.
The scheme of attaching the loading tray is simple and excellent and
warrants consideration. It may be well to mention that although
the groimd platfonn of this requires some time for its installation,
it is neverthheless easy to conceal after it is installed, smce the ap-
proach tracks may be removed and the mount completely covered.

350. Demerits. — ^The one apparently bad feature which has been
mentioned likewise under the head of Merits, is the firing platform. At
the beginning of this section it was mentioned that criticism would be
made of the firing platform on a basis of the ideal apparently attain-
able. The steel platform, however, required seven cars for its trans-
portation and can not be installed in less than from three to five days.
The concrete platform can probably be installed in the same length
of time and of course, with fewer facilities. It seems possible to
design a mount in which the same general features may be embodied
but which will not require such elaborate accex^sory equipment in
the shape of a platform as is used here.

CRADLE, RECOIL CYLINDER, AND SPRINO RECDPEHATORS OP THE 310-MlI.
neRUAN GUN MOUNT.

p. ELEVATINQ WORM, AND ANTI-FRICTION BEARING OF THE
210.MM. GERMAN CUN MOUNT.

483

19.— GERMAN 240-MILLIMETER HOWITZER ON RAILWAY MOUNT.(32)

351. This mount is of the cradle recoil type, firing either from the
wheels with limited traverse or from a structural steel or reenforced
concrete platform w^ith all round fire. It is of the same general type as
the 210-millimeter mount just described and only the differences be-
tween the two mounts will be described in detail. The mount exam-
ined bears the date ** Essen 1918." It is illustrated on plates 377 to
383. Apparently, the mount was designed for a 240-millimeter gun,
since the counterweight provided on the top of the cradle gives evi-
dence of being a recent improvisation placed there to compensate for
the difference in weight forward of the trunnions, between the gun
and howitzer now mounted on it.

352. Gux. — The howitzer is a naval piece of 30 c-alibers over-all
length and uses semi-fixed ammunition. The tube is rifled with 52
grooves twisting to the right at a uniform pitch of 1 centimeter in 10
centimeters. The breech block is of the Krupp sliding wedge type
and is provided with a high-pitch screw for closing and a low-pitch
screw for locking. The breech block is fitted with a mechanical
firing mechanism.

353. Recoil Mechanism. — The recoil mechanism is of the hydro-
pneumatic type and comprises two hydraulic recoil cylinders set into
the cradle in the upper corners, and a pneumatic recuperator attached
to the cradle in the center at the bottom. The pistons of the recoil
cylinders are attached to the recoil band as shown on plate 379 and
the forward end of the recuperator piston is connected with the
bottom of the recoil band by means of a cross head and two tension
rods, plate 380. The length of recoil is about 1 meter. The striking
feature of this mechanism is the recuperator. The piston is a hollow
plunger of uniform diameter facing the air directly and the packing
which holds the air in, consists of four U-shaped leathers only. When
the recuperator was disassembled, it had been standing for months
without recharging but it still contained a very high pressure of air-
The indicator was broken and it is not known exactly what the
pressure was. The recoil band of this howitzer is made in halves
and is bolted on, as shown in plates 379 and 380.

354. Elevating >[echanism. — This mechanism is similar in gen-
eral design to that on the 210-millimeter mount. The differences
are that the main racks, plate 380, have outside instead of inside
teeth and are of much wider face. An antifriction device of the
rolling w^edge type, plate 382, is employed. The double-speed trans-
mission on the elevating gear, plate 381, is identical in design with
that used on the 210-millimeter mount.

355. Traversing Mechanism. — Two systems of a design almost
identical with those used on the 210-millimeter mount are provided.

The noticeable differences are thai the truck traversing mechanism
gives 2 degrees on each side of the center or 4 degrees total as against
2 degrees on the 210-millimeter mount, and the rear traversing rollers
are housed in and geared t<^ether.

356. Gun Carriage. — ^The gun carnage is incorporated with the
car body and is described in the next paragraph.

357. Railway Car Body. — ^The gun is carried in a cradle of curi-
ous boxlike design, 45 inches by 52 inches by 105 inches, built up of
castings and planed plates, plate 377. This cradle is suspended by
means of its trunnions in cast-steel bearings mounted on the side
girders of the car. As mentioned before, apparently the mount was
originally designed for a 24^entimeter gun. Counterweights mounted
above and below the gun and forward of the trunnions, plate 377, have
apparently been added recently to compensate for the difference in
the muzzle weight of the gun and howitzer. This cradle carries the
recoil cylinders in its upper corners and the recuperator cylinders in
the center at the bottom. The car body is similar in general design
to that of the 210-millimeter mount, but differs considerably in its
details. The car body is made up of two single web structural steel side
girders connected by a number of structural steel transoms. Jacking
beams are incorporated in the car body at the forward and rear ends,
plates 377 and 383. These side girders are 39 inches deep over the
front and rear trucks as against 28 inches for the 21 -centimeter. This
mount is likewise more liberally supplied with armor than the 21-
centimeter mount.

358. Anchorage. — See * 'Anchorage*' under the 210-millimeter
mount.

359. Trucks. — See * 'Trucks-' under the 210-millimeter mount.
They are identical.

360. Ammunition Supply System. — This is practically identical
with that of the 210-millimeter mount, with the exception that tha
tray is not supplied with wheels and apparently is not used in carrying
the shell. The shell is carried forward by means of the tongs, plate
392, and placed on the tray which is hooked to the breech of the gun.

361. Maintenance. — See '^Maintenance" for the 210-millimeter
mount. Some additional maintenance probably results from the use
of a pneumatic recuperator.

362. Difficulties Involved in the Service. — See the same for
the 210-millimeter mount.

363. Merits.— See ''Merits" for the 210-millimeter mount. The
one exception is in the case of the antifriction device of the rolling
wedge type, which does not appear to be so admirable a design as the
roller bearing.

485

364. Demerits. — See ^'Demerits'' for the 210-milliineter mount.
Additional criticisms may probably be made on the construction of
the cradle. On further study it might develop that there are some
advantages in the use of this quite clumsy looking cradle, but none
are apparent now. It is possible that this cradle is an improvisation
and was so constructed as to avoid the making and machining of a
large casting.

365. Although it possibly has no place here, it may be well to
mention that, in these three mounts, the 21(>-millimeter, the 240-
millimeter, and the 28(>-millimeter, there are a great many differences

«

in the design of details that do not seem to have any logical explana-
tion. On the 240-millimeter mount the traversing rollers are housed
and geared together, the elevating rack meshes on the outside, and
antifriction device is of the rolling-wedge type, and the rear truck
traverse is 4 degrees. On the 210-millimeter mount the traversing
roUers are neither housed nor geared together, the elevating rack
meshes on the inside, the antifriction device is of the roller type, and
the rear truck traverse is 2.25 degrees. On the 280-millimeter mount
the traversing rollers are housed and geared together^ the elevating
rack is straight, the antifriction device is of the roller type, and the
rear truck traverse is 2 degrees. Apparently the three mounts can
be operated on the same platform. Just why these minor variations
in design were made is not at all evident.

210-MM. GERMAN HOWITZER ON RAILWAY MOINT <REAR VIEW).

RREECH.CttADLE.AND LOADING TRAY OF THE 210-UU. GERMAN BOWITZEK.

ELEVATING KACK AND RECUPERATOR OF THE 240-MM. GERMAN' HOWITZER.

4^

493

20.— <SERMAN 240-MILUMETER GUN ON RAILWAY MOUNT. (33)

366. On plate 384 a 240-inillimeter gun is shown on a type of
railway mount resembling more the 38-centimeter mount than the
design used with the 21 and 24 centimeter mounts already described
in detail. The writer has not had an opportunity to examine a
mount of this type and to the best of his knowledge none of them
were captured. Xo attempt will be made to describe it in detail.
Attention is called to certain features easily seen on this plate. The
mount is carried on two four-axle trucks, the axles having inside
journals. This is the first German mount observed on which inside
journals have been used. On the horizontal portion of the lower
cords of the side girders a number of plates which appear to be key
plates can be seen, and it is assumed that this mount was operated
on a turntable type of emplacement somewhat similar in design to
that used with the 38-centimeter railway mount. It is probable
that the key plates mentioned engaged with similar plates on the
racer of the emplacement. It is probable that hydraulic jacks were
placed under the four corners of the car body after it was in position
over the emplacement to raise the mount for the purp(>se of removing
the trucks.

495

21.— GERMAN 280-MILUMETER GUN ON RAILWAY MOUNT. (34)

367. This mount is of the cradle recoil car traverse type, firing
either from the wheels with limited traverse or from a structural
steel or reinforced concrete ground platform with- all round fire. It
is similar in type to the 210-millimeter gun and 240-millimeter how-
itzer mounts already described and operates from the same ground
platform. Three batteries of these mounts operated from concrete
platforms were included in the German defenses on the coast of
Belgium. (See Appendix III for description of these.) The mount
examined and illustrated herein was captured by the British Fourth
Army before Amiens, on August 8, 1918, in the great offensive being
waged by the Allies at that time. It was exhibited for a time in a
railway yard in Paris and later was taken to England. To the best
of our knowledge this was the only mount carrying a gun of this cali-
ber that was captured. The Belgian Army captured several 17-
centimeter mounts and one 38-centimeter mount, and the Americans
have two 17-centimeter one 21 -centimeter, and one 24-centimeter
mount. These mounts are illustrated on plates 385 to 399, 36, 55
and 56.

368. Gun. — ^The gun on the mount examined is a 40-caliber naval
piece of model 1914 of 42 calibers total length. The tube is rifled
with 80 grooves having a uniform twist to the right of 1 centimeter
in 10 centimeters. The breechblock is of the ordinary Krupp
sliding wedge type and is fitted with a mechanical firing mechanism.
As with all other large guns having this type of breech, this gun
uses semifixed ammunition.

369. Recoil Mechanism. — The recoil mechanism is of the hydro-
pneumatic type and comprises one pneumatic recuperator cylinder
mounted at the bottom of the cradle in the center and two hydraulic
cylinders likewise mounted on the bottom of the cradle and on either
side of the recuperator cylmder, plate 36.

370. Elevating Mechanism. — The elevating mechanism com-
prises two straight racks, plate 387, engaging with two pinions
inclosed in floating housings and attached to one shaft. This shaft
is connected by means of a worm, wheel, and shaft and on the right
side of the gun with elevating handwheel shown near the elevation
quadrant.. This is the only railway mount so far observed in any
of the armies in which the attempt has been made to use this straight
rack, which is much more easily machined than any of the usual
curved elevating racks. On the under side of the floating housings
two rollers are carried on which the back of the rack rides and which
hold the rack in perfect mesh with the pinions. These two racks
are attached by means of heavy pins to the rear of a cradle. The
cradle trunnions are provided with the same roller type of anti-

181768—21 32

496

friction device used on the 21-centimeter mount, already described.
The mechanism used on this mount is shown on plate 388. An
elevation arc, plate 403, is attached to the cradle on the right side.

371. Traversing Mechanism. — See '* Traversing Mechanism" for
the 21 -centimeter railway mount. The design of the car traversing
mechanism over the rear truck is shown on plates 390 and 391, and
the mechanism used in giving the mount all round traverse is shown
on plates 392 to 395. The traverse rollers on the 21-centimeter
mount are separate and exposed, while on this mount, plate 396,
they are housed in and geared together.

372. Gun Carriage. — The gun carriage is incorporated with the
car body and is described in the next paragraph.

373. Railway Car Body. — The gun is carried in a cradle of the
design shown on plate 36. The cradle is provided with a heavy
counterweight just above the trunnions to raise the center of gravity
of the tipping parts sufficiently to permit of easy elevating and
depressing. This cradle is suspended by means of its trunnions in
cast-steel bearings mounted on the side girders of the car body.
Each of the trunnions is provided with an antifriction device of the
design shown on plate 388. The car body is built up of two single
web structural-steel side girders connected by a series of structural-
steel transoms and deck plates and the car platform is covered with
light armor, plate 385. Both the traversing roller housings and
center pivot trunnion bearings are bolted to the bottom of the side
girders and serve to stiffen it. Jacking beams, which, in the case of
the mount examined, had the jacks attached, plate 385, are carried
under the forward and rear ends of the car body. The car traversing
mechanism, a part of which forms the upper center plate over the
rear truck, can be seen on plate 391.

374. Anchorage. — See ^^Anchorage" for the 21-centimeter mount.
The emplacement shown on plate 397 was used with batteries installed
along the Belgian coast. This battery is only about 1 mile north of
Ostend. The designs of the concrete and structiu^al-steel platforms
and the emplacing jacks are shown on plates 55, 56 and 398.

375. Trucks. — The two trucks on this mount, plate 385, are
practically identical. The frame is of structural steel and each
carries five axles with outside journals. The brakes are operated by
hand only, and the end and center wheels are provided with two
brake shoes each. Above each spring clip there is a capstan head
screw, identical in design with those used on the 21 and 24 centi-
meter mounts, which is run down hard on the clip to relieve the
springs of undue strains in firing from the track.

376. Ammunition Supply System. — The ammunition car captured
with this mount is a wood box car of apparently standard design,

497

tilted with racks to cany 25 projectiles, plate 397. These projectiles
are carried to the forward end of the car by means of an overhead
trolley and are lifted through the roof of the car by means of a
chain hoist on the end of the extension of the trolley track in the
cab of the mount. It is carried forward by this second trolley, and
placed on a tray attached to the breech of the gun, similar to those
used with the 21 and 24 centimeter mounts. The projectile is rammed
into the gun from this tray by hand. All of the projectiles in the
car had an ogive of 10 calibers radius and all were fitted with false
caps. The caps were placed on the projectiles as they were used.
In the end of the cap there is a tapped hole through which a stick
of wood is passed until it rests against the fuse. Considerable pres-
sure is brought on this piece of wood w^hen the small plug is screwed
into the end of the cap. AH of the projectiles captured were provided
with time fuses of the 90-second clockwork variety.

377. Maintenance. — ^There are no apparent difficulties in the
maintenance of this railway mount, all parts of which are very simple
and substantially constructed. The elevating, traversing, and load-
ing mechanisms had all seen considerable service, and yet no apparent
difficulties had developed. The trucks had likewise apparently
given no difficulty. It is not known just what difficulty may have
been experienced with the recoil mechanism, but probably com-
paratively little.

378. Difficulties Involved in Service. — See same for the 21
and 24 centimeter mounts.

379. Merits. — See same for the 21 and 24 centimeter mounts.

380. Demerits. — See same for the 21 and 24 centimeter mounts.

ANTI-FRICTION BEARING OF TUB SW-UU. GEBUAN OUN H

ELEVATING ABC OF THE 280-MM. GERMAN GUN MOUNT.

503

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507

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CENTER PIVOT OF THE 280-M\f. GERMAN GUN MOUNT.

508

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TRAVERSING MECHANISM OF THE 280-MM. GERMAN GUN MOUNT.

LE8 AND AUUUNITION CAR FOR THE 280-HM OERUAN OUN UOUNT.

513

22.— GERMAN 380-MILUMETER GUN ON RAILWAY MOUNT. (35)

381. This mount, plates 400 and 401, is of the cradle recoil type,
firing from the wheels with limited traverse to an elevation of about
18 degrees, or from a structural-steel turntable type of ground plat-
form with all round fire. The mount examined was captured by the
Belgians and is in serviceable condition. Emplacements on which it
could have been operated have been found in only two places, the one
in the Forest of St. Gobain, west of Laon, and the other in the Bois de
Chatelet, about 5 miles north of Chateau Thierry. All evidence avail-
able to-day indicates that while it was being operated from the em-
placement in the Forest of St. Gobain it was serving as a mount for
the long-range guns, all of which were made from worn-out 38-
centimeter, 45-caliber naval guns. The mount bore the date of
February, 1918, at which time it was probably completed by the
firm of Krupp, and the evidence available to date indicates that it
was the onlj' mount of this design that they had. Gen. Amoulde,
Chief of Artillery of the Belgian Army, informed the writer that the
mount had been found on a special track in the Bois de Leugenboom
near the permanently emplaced 38-centimeter gun in that same
woods, about 10 miles south of Ostend. There was no evidence that
it had ever been operated from this position.

382. Gun. — ^The gun found on the carriage inspected was of the
1916 model and was number 33L. The total weight is 77,552 kilo-
grams. The total length of the gun is 17.13 meters and the distance
from the face of the breech block to the muzzle is 16. 13 meters,
making the gun about 42 calibers long. This is very significant,
considering the fact that the gun is supposed to have a range of 55
kilometers (50,095 yards). The breech is of the standard Krupp
sliding wedge type, the wedge being operated by one handle through
a series of spur gears, to One screw.

383. Apparently the gun, plates 400 and 402, is built up of five
main sections; the tube is reinforced by two hoops which are further
reinforced by one jacket extending from the breech forward about
two- thirds of the length, and a breech section attached to the last
named jacket by the recoil lug. In the case observed, the tube has
evidently lengthened to the extent of about 0.562 inches. The
evidence of this is the extension of the tube beyond its original
position with reference to the end of the forward hoop a distance of
^bout 0.187 inches and the parting of the forward hoop from the
hoop to the rear to the extent of 0.375 inches. This same condition
was observed on several other guns of this design. The number of
grooves is 100. The width of the grooves is approximately 0.219
inches, and the width of the lands 0.236 inches. The lands show
slight signs of wear on the driving side and copper was visible both on

514

the lands and in the grooves at the muzzle of the gun, although not
to such an extent as probably to have much effect. The diameter
of the powder chamber is 42.5 centimeters. The recoil lug to which
the two pistons of the hydraulic cylinders and the one piston of the
recuperator cylinder are attached likewise serves to prevent rotation
of the gun. It is forked at the bottom and bears on two sides of the
recuperator cylinder which serves as a guide, plates 403 and 404. In
this connection, it is significant that with every heavy German gun
observed, rotation of the gun was prevented in this same manner,
the breech lug having an extension which either bore on two sides
of a recuperator cylinder or between two recuperator cylinders. It
is certain that there were no cases of a spline on the gun sliding in
a way in a cradle. In traveling, the gun is locked in battery by the
very simple device shown on plate 402.

384. This gun is identical in design with the guns of the Battery
Deutschland and the Battery Pommern, at Leugenboom, described
in Appendix III. The guns of these batteries are accredited with a
maximum range of 55 kilometers. In the report which was examined
in Gen. Arnoulde's office, the range was given as 42 kilometers.
There is no question but that the Battery Pommern fired on the
city of Dunkirk, requiring a range of 45 kilometers. Whether the
Battery Deutschland, which is 2 kilometers northeast of Ostend,
likewise fired on Dunkirk is a question. The basis for the statement
in the Bulletin de Reseignements de I'Artillerie of January-February,
1918, crediting these guns with a range of 55 kilometers is not known.
Whether the provision for an elevation of 55 degrees has any real
connection with the unusual range of a gim 42 calibers in length and
credited with a muzzle velocity of 800 meters per second, is not
known definitely. It seems certain, however, that the specification
given the designers for a maximum elevation of 55 degrees resulted
in the type of elevating mechanism described later.

385. Recoil Mechanism.— The recoil mechanism is composed of
two recoil cylinders and one spring pneumatic recuperator cylinder,
all located on the bottom of the cradle, plates 403 and 404. Each of
the recoil cylinders is a separate cylinder carried in brackets cast on
the cradle and each is provided with a bufi'er approximately 32 centi-
meters long. The filling plugs are on the ends of the buffers. The
maximum length of recoil is 1.3 meters. This distance is, of course,
approximate, and was arrived at after careful examination of all of
the apparatus. In a report examined in the office of Lieut. Gen.
Amoulde at Brussels, the length of recoil was given as 1.15 meters.
On inquiry, it was found that this was likewise an estimate. Two
rods screwed to the recoil lug and extending to the rear, plate 403,
carry a cross head to which the piston of the recuperator cylinder is

515

attached. The recuperator cylinder, plates 405 and 406, is likewise
a separate cylinder carried in brackets cast on the cradle, and at the
rear on both sides it is planed to serve as a guide for the recoil lug, to
prevent rotation of the gun.

. 386. Elevating Mechanism. — ^The elevating mechanism of this
mount is unique in several respects. Provision is made for elevating
the gun from 0 degrees, the loading angle, to 55 degrees. It is com-
posed of two straight racks, plate 407, driven through pinions, a
wormwheel, worm, a double speed transmission, sprockets and
chains, by four two-man handles, plates 408 and 409. The straight
racks slide in ways which are parallel to the inclined lower face of the
forward end of the side girders. It was necessary to put them in
this position to secure* sufficient movement to elevate the gun to 55
degrees. At the lower end, they are connected with each other by
a heavy shaft, plate 407, to which are attached the two connecting
rods running up to the bottom of the cradle. It will be observed,
plate 409, that provision is made for two handles on each side of the
car, each for two men. A double speed •transmission, similar in
design to those used on the 21 and 24 centimeter mounts is incor-
porated in this mechanism. The ratio on the low gear is 4.125
turns of the handle for one degree of movement of the gun. One
man can operate the elevating mechanism with some difficulty at
low gear. It seems probable that eight men could operate the high
gear without serious difficulty. The gun and cradle were identical
with five others observed in the coast defenses of Belgium. On all
of the other guns, however, the elevating mechanism included
double telescoping screws. It is probable that this gun when used
on a ship or in the coast defenses was likewise so elevated, and that
it was impossible to accommodate this mechanism, on a railway
mount and secure the elevation desired. It is likely that under the
specification of such an extreme elevation no other type of mecha-
nism could have been adapted to this cradle and mount without
serious difficulty. tTudging from the diagram, plate 404, which was
made up from measurements of the gun and cradle and the estimated
length of recoil of 1.30 meters, it seems probable that the gun can
be fired from the track, the mount operating as a roDing mount, to
an elevation of 18 degrees, 30 minutes. If the length of recoil is
1.15 meters, as given in Gen. Arnoulde's report, it is probable that
an elevation of as much as 20 degrees can be secured. The gun can
be fired above 18 degrees only from a special emplacement.

387. Traversing Mechanism. — This mount is provided with a
car traversing mechanism installed on the front span bolster, giving
a maximum traverse of 1 degree on each side of center. This mecha-
nism, which includes the usual screw, plate 411, is operated through a

516

series of spur gears and chains, plate 412. There seems a good reason
for providing a high and low speed elevating mechanism, but just why
the designers provided both high and low speed on this traversing
mechanism is not known. In comparing this design with French and
American designs, it is significant that no rollers are provided between
the body of the mount and the span bolster. Cast-steel shoes narrow-
ing down to a wedge are provided on each side, plate 426. The
designers evidently preferred to count on an ample supply of man
power rather than provide the usual rollers. A second traversing
mechanism for alUround firing is installed in the emplacement, plates
419 and 420. In this case the racer of the emplacement rests and
rotates on 112 8-inch steel balls. A complete circular traversing rack
made up of angles and steel pins is bolted to the structural steel base,
plate 419. A pinion carried on a vertical shaft on the side of the
racer which corresponds to the rear of the carriage engages with this
rack, and the mechanism is driven either from two 2-man handles
on shafts carrying a worm engaging with a wormwheel on top of this
vertical shaft or by means of four handles carried in gear cases on
either side of the mount, plate 420. Motion is communicated to the
vertical shaft from these four handles through two shafts carrying
two universal joints each. These latter handles are apparently the
ones ordinarily used, if one may judge from the scheme of operation
shown on plate 422. •

388. Gun Carriage. — ^The gun carriage is incorporated in the car
body and will be described in the next paragraph.

389. Railway Car Body. — ^The cradle is a cylinder of simple
design having ribs at long intervals and of a depth of only about 3 centi-
meters. Other cylinders observed for the same design of gun were
without any ribs whatever. The walls of the cylinder have a mini-
mum thickness of 10 centimeters and a maximum thickness of 13
centimeters over the ribs. The design of the antifriction mechanism
is shown on plate 414. As shown on plate 411, a counterweight in
two sections is attached to the top of the cradle. Both sections can
be raised and locked together, or, if desired, the rear section raised
and locked in place by the two tie-rods. The railway car body,
plates 400, 413, 414, and 415, is made up of two single-web side
girders connected in the front and rear by heavy structural-steel
tran3om8 and further reinforced in the front by the heavy cast-steel
housings for the elevating mechanism. The trunnion bearings are
of cast steel and are simply bolted to the top chord with single keys to
the rear of them. These single key^ have the positive backing of one
top cover plate each. The face of the horizontal section of the lower
chord of the side girders is planed and is provided with a key at each
end, plate 416. Eight 2-inch holes are provided in each lower chord

517

at the front end and six at the. rear. The purpose of the hooks
shown on the front is not known.

390. The designers avoided the use of sharply curved angles, plate
415. There are only two slight curves on the angles of the lower
chord. The working platforms provided on each side to the rear of
the trunnion seat are locked in their traveling positions, as shown on
plate 425.

391. Anchorage. — ^The gun can be fired to a maximum elevation
of 18 degrees 30 minutes with the mount operating as a rolling mount.
Above this elevation the trucks must be removed and the mount is
operated from a fixed emplacement.

392. In August, 1918, when the German Army had retired from
the salient between Soissons and Rheims, the emplacement shown on
plates 417 and 418 was found in the Bois de Chatelet. All evidence
indicated that this emplacement had not been used in this position.
It was simply in process of erection when it was abandoned. The
Germans attempted to destroy it, but succeeded only in ripping loose
a few plates. At the time that this emplacement was captured, no
descriptions of any kind were available of the carriage for which it
was intended. The writer's failure to find any emplacement in
Belgium from which the mount could be operated led to a search for
emplacements in France, and an examination, of the emplacement
shown revealed the fact that it was the one sought.

393. The mount is run in on the emplacement in a position shown
approximately on plate 417. It is then raised by four jacks, one of
which can be seen in the left foreground on plate 419, and the trucks
removed. The rotating section of the emplacement is then turned
90 degrees, and the carriage lowered onto the side girders. In the
right center of plate 417 is shown one of the key plates, which cor-
responds to a similar plate on the bottom chord of the carriage girders,
plate 426. The six bolt holes shown in the key plate on plate 418
correspond to the six holes in the lower chord on plate 426. On this
plat« only the bolt holes on the outside of the girder web are visible.
From the fact that the key plates for the forward end must have
eight bolt holes and those for the rear six, it is evident that the
traversing mechanism is located on the part of the emplacement
corresponding to the rear of the carriage.

394. It is necessary to install two auxiliary construction tracks on
either side and parallel to the approach track for the service of the
Gantry crane used in installing the emplacement. Ope of these
tracks is shown on plates 417 and 418 and both are shown in both
elevation and plan on plates 419 and 420. The emplacement, as
well as the Gantry crane used in the work of installation, are shown on
plate 421. German handbooks allow a period of three weeks for the

518

installation of the structural-steel emplacement. The mount is
shown completely installed and in operation on plate 422. This
plate is made from a cut contained in a printed publication of the
Krupp Co., which manufactured the mount.

395. Camouflage. — In the case of the emplacement found in the
Bdis de Chatelet, sockets were placed in the center of the approach
track at intervals of about 30 feet, into which trees with trunks up
to about 6 inches could be placed for the purpose of concealing these
tracks.

396. Trucks. — ^AD of the trucks, as well as the span bolsters, are
constructed entirely of structural steel, plate 401. The front trucks
contain five axles each and the rear trucks four axles each. The
journals are approximately 14 centimeters in diameter by 32 centi-
meters in length, and the wheels are 95 centimeters in diameter.
On the front trucks, three wheels have two brake shoes each. On
the rear trucks, the end wheels have two shoes each and the inner
wheels one shoe each. The braking is done by hand only. A por-
tion of the circular track on which rubbing plates attached to the
span bolster on each side bear, can be seen on the front truck, plate
400. There are no rollers on any of the trucks or bolsters. The
axles are equalized in pairs only, the center axles of the front trucks
having no connection with the others, plate 423. The various di-
mensions of the trucks are given on plate 401.

397. Ammunition Supply System. — ^The provision made for sup-
plying ammunition when the mount is operated on the emplacement
is shown on plate 424. This narrow-gauge ammunition track can be
seen likewise around the pit on plate 422. ^ The indications are, from
plate 422, that the track formed a loop around the pit in this case
and that it was not a complete circle with turntable as was found in
other emplacements in Belgium. A removable plate can be seen be-
tween the shot truck rails on the operating platform of the mount,
plate 425. Over this plate is a light bridge, in the center of which is
seeVi a ball on the end of the cable used in hoisting projectiles through
the hole in the floor. The cable (0.5-inch) runs over a series of pulleys
to a small drum in the box on the top of the left-side girder.

398. The ammunition is supplied from the storehouse over the
narrow-gauge track already mentioned, the portion of the track
around the pit being under the opening in the working platform.
The projectile is raised by means of tongs attached to the hook
under the ball and when at the top of the bridge the shot truck is
run forward and the projectile placed on it. The shot truck inspected
has no buffers, but four holes can be seen in the flange on the front
which may have been provided for the attaching of a pad of some
sort. The clear space over which the men could get up speed with
the truck is about 5 meters. The gun is loaded at 0 degree ele-

519

vation. It is understood that the projectiles of the 38-centimeter
gun of the same design at Leugenboom were rammed by 12 men.
It is probable that the same number of men were used on the railway
mount.

399. When the mount is operated as a roDing mount, the ammu-
nition is supphed directly from the ammunition car. This necessi-
tates the use of the extension to the car body, which extension, by
the way, gives one the impression of having been an afterthought.
This extension is pinned to the rear of the car body and is likewise
connected by means of the two tie rods shown on plate 426. These
tie rods do not seem absolutely necessary since the weight of the
extension is carried by the rear truck. When the shot truck is at
the end of the extension, the projectile can be placed upon it from
the trolley that extends a short distance from the end of the ammu-
nition car. When operated as an emplacement moimt the extension
of the car body was removed.

' 400. Maintenance. — ^There seems to be no evidence that this
mount involved any difficult problems of maintenance. The design
^ simple throughout and quite sturdy. It is not known how much
difficulty they may have had in maintaining the desired air pressure
in their recuperator cylinder. It will be observed on plate 413 that a
smaU pump is provided on the left side of the mount, which presuma-
bly was provided for charging the recuperator. A gauge at the rear
of the recuperator cylinder gave evidence of the existence of a floating
piston. The gauge on the top of the cradle, plate 402, is capable
of registering a pressure of 250 kilograms per square centimeter. If
the pressure maintained in the recuperator was even half the pressure
which the gauge was capable of registering, it is possible that they
may have had some difficulty in maintaining their recuperator.

401. Difficulties Involved in Service. — ^The mount is operated
above 18 degrees 30 minutes from an emplacement of the type
shown on plates 417 and 418. Any such contrivance as this is con-
sidered a decided nuisance and would not be tolerated in our own
designs; neither would it be tolerated by any of our allies. It is
significant that in German handbooks the time aUowed for installing
gun emplacements is usually from three to five times as great as that
permitted in the American Army. It is probable that the full three
weeks allowed was required for the installation of this emplacement.
No other difficulties are apparent in the service of this mount

402. Merits. — ^The simple design of cradle, generally simple de-
sign of the mount throughout, convenient ammunition supply system
and high elevation, may be classed as merits.

403. Demerft. — ^The necessity for the use of an emplacement of
this type for the operation of the mount at high angles is a decided
demerit.

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546

SECTION 4.

PRACTICAL QUALinCATIONS OF RAILWAY ARTILLERY FOR
LAND WARFARE AND COAST DEFENSES.

404. To arrive at a proper conclusion with reference to the quali-
fications desirable in railway artillery, the relative merits of various
details of design, as brought out in sections 1 and 3, will be con-
sidered first. Next, the various services required of the pieces will
be given as discussed in section 2, and the general characteristics
necessary in a mount to satisfy each service wilt be determined.
Finally, on the basis of the above discussions, the best combination
of design details to satisfy the requirements of each mount will be
recommended.

RELATIVE MERITS OF DESIGN DETAILS.

405. Design details will be considered under the same headings
used in describing them in section 3. In addition, attention will be
given to special requirements for coast defense.

406. Gun. — Practically all of the guns used on railway mounts are
of old or obsolete design. None of the novelties of design brought
out by the war were developed to a point of actual utilization on
railway mounts. A few of these new ideas are briefly described
below, however, as they may develop to some importance in relation
to railway artillery.

407. Autofrettage is a system of gun-tube construction in which
the distribution of initial stresses (which is ordinarily obtained by
the shrinkage of concentric rings, one upon the other) is attained in a
single homogeneous tube, or better, in one tube and one jacket,
through the application of internal hydraulic pressure. This system
has not yet.been applied to the manufacture of anything larger than
field guns. It has been used, however, in the making of the French
long-range gun. The 33-meter tube of 21 centimeter bore, used in
converting a 34-centimeter, 45-caliber naval gun into a long-range
gim, was placed in the gun cold and expanded by hydraulic pressure.
The hoop placed over the projecting portion of the tube was likewise
put on cold and the tube expanded into it by hydraulic pressure.

408. ** Artillery C is a term used by the French to designate an
experimental system of M. Charbonnier, in which copper rotating

(547)

548

bands are replaced by machined rifling on the shell. The rifling ixi
the gun is made to correspond, and the shdl is made longer and heavier
than normal. Experiments have been made in 75 and 155 milli-
meter field guns along this line, in which shells up to 9.5 calibers in
length and weighing 60 per cent more than the regulation shell,
were fired and attained ranges up to 35 per cent in excess of the range
for the standard shell.

409. The turbo-cannon of Lieut. Delemerr-Mayo, of the French
Army, is a gun without rifling, in ^hich the rotational velocity is
given the projectile by the impact of the poi;rder gases on special
vanes. Such tests as were made indicated rotation of the projectile,
but no further conclusions were possible.

410. Muzzle brakes, or gas deflectors, for reducing recoil have been
experimented on by Lieut. Bory and Capt. Galliot, as well as in the
American Ordnance Department. The best results so far attained
in experiments are a reduction of 40-60 per cent in recoil energy on
the 75-millimeter field gun and a reduction of 83 per cent on a 3-inch
seacoast gun. Measurements taken of the atmospheric pressures in
the case of the seacoast gun indicate that the gun crew is not in any
danger from the outwardly deflected gas stream.

411. Recoil Mechanism. — ^The various recoil systems were dis-
cussed very fully in section 1 , and the following points were brought
out:

(a) Cradle recoil with air recuperator is the highest develop-

ment of recoil systems.

(b) Top carriage recoil is obsolete, being particularly un-

suited to high-angle fire.

(c) Sliding recoil is unsuited to small guns because the time

of firing can not bo reduced below a minimum which
is too great for the efficient service of such guns. With-
out the use of a cradle, it is unsuited also for the very
largest guns, on account of excessive trunnion forces.
It is very satisfactory for medium and large calibers.

(d) Rolling recoil is similar to sliding recoil in regard to the

pomts mentioned above. A rolling mount requires less
track preparation than any other type. In all known
types of rolling mounts cradles have been used, makmg
them more complicated than the sliding mounts.

412. Mounts with rolling or sliding recoil must be pushed back
hito battery after firing. This is accomplished on the lighter of the
sliding type mounts by the use of a hand translating mechanism,
consisting of a crank, a train of gears, and some chains leading to
one or more of the axles. In the mounts constructed to date one
translating mechanism is provided on one or two of each four to six

549

axles, and the ratio of gearing is from 100 to 132 turns of the handle
to one revolution of the wheel. The mount can be moved at the
rate of from 8 to 5 feet per minute. With the mounts having rolling
recoil, the length of recoil is considerably greater and a gasoline-
driven winch, mounted on the front truck or span bolster and taking
up a cable fastened to the track ahead, is preferred for returning
the mount to its firing position. For this sort of movement, exper-
ience has showTi that the rollmg friction is much greater than is
ordinarilv assumed for railwav work. The tractive effort on a level
track with the American 16-inch howitzer ran up to 50 pounds per
ton. On the heaviest sliding mounts electrical translating mechan-
ism is provided. This is very convenient, of course, but requires a
power plant and complicates the design and accessory equipment.
Manpower is always available and is reliable. Electrical equipment
has the bad habit of failing when it is needed most.

413. Elevating Mechanism. — Elevating mechanisms are so
diverse in type, and the speed of operation of the piece is so largely
dependent on them that a somewhat lengthy consideration is felt
to be justified. First the requirements of the mechanism will be
discussed, and then their practical embodiment will be described.

414. The requirements of an elevating mechanism are thai; it
shall:

(a) Afford proper extent of elevation.

(6) Give proper ratio of handwheel to gun movement.

(c) Be sufficiently strong to withstand shocks of fire.

(d) Be efficient enough to allow operation at the required

speed with the power available.
Ce) Be simple in construction and easily maintained.

415. In regard to extent of elevation, (a) above, ideas have been
modified considerably by the experience of the European War. For
howitzers, a maximum elevation of 65 degrees is required to give
the desired plunging fire. For guns there may be objectives at long
ranges of such size that the high dispersion incident to fire at maxi-
mum range is not disadvantageous. Therefore the mount should
always allow sufficient elevation for the gun to attain this maximum
range. For medium caliber guns at medium velocities, this approxi-
mates the theoretical 45 degrees. For large guns and high muzzl^
velocities, however, the decreased air resistance at high altitudes
so far increases the range that the maximum appears to be attained
at from 50 to 55 degrees. The long range 21()-millimeter German
gun which operated at a muzzle velocity of 1,500-1,600 meters per
second, was fired at an angle of at least 55 degrees. The French
220-millimeter gun will be mounted with provision for an elevation
of 55 degrees.

550

416. The ratio of handwheel to gun movement, (b) above, will
be expressed as the gun movement in degrees over the corresponding
handwheel movement in turns, 2/1 meaning 2 degrees of gun move-
ment per revolution of handwheel. This ratio should be such that
the necessary fine adjustment for laying can be had, on the one
hand, and that the gun may be depressed and elevated rapidly for
loading. On some of the older mounts, the ideal for both require-
ments is sought by the use of a slow elevating gear and a quick
loading mechanism together, as on the 190, 200, and 240 millimeter
French howitzers. Railway artillery, however, is riot called upon
for extreme speed in firing, and late designs of mounts show that a
satisfactory compromise can be found in a single mechanism. As
an indication of the requirements for accurate laying, it is found that
the adjustment of elevation to a precision corresponding to one
quarter of the probable error in range, requires setting to within
from 1 to 2.5 minutes, depending upon the accuracy of the particular
gun considered. Such a setting could easily be made with a hand-
wheel ratio of 1/1 to 2/1. The smaller handwheels can be spun at
from 60 to 90 revolutions per minute, which would give a speed of
operation to 45 degrees elevation, of from 15 to 45 seconds. This
is amply fast enough for railway artillery. Practice shows a varia-
tion of this value per tiurn of handwheel between about 0.33/1 and
1.80/1. The ratio for the heaviest guns approximate a value of
0.5/1, but as Qne of them which has an efficient elevating gear, has
a value of 1/1, it is thought the lower value is adopted for the sake
of mechanical advantage, rather than because it is inherently desir-
able. The conclusion from the above is that a ratio of 1/1 (1 degree
movement of gun per revolution of handwheel) is amply fine enough
and that the value may be run up to 2/1 with the less accurate
and smaller guns.

417. In reference to strength (c) above, the chief forces to be with-
stood are two. The first is a turning moment due to the powder
pressure. In American ordnance design, the center of gravity of the
recoiling parts is usually put a short distance below the center line
of the gun, so that, as long as the projectile is in the bore, there is a
couple due to the powder pressure against the breech, which tends
to elevate the gun. The elevating mechanism must be made strong
enough to stand this without movement, so that the accuracy of fire
will not be reduced. The second force is the moment due to the
breech preponderance of the gun when in full recoil. If the elevating
mechanism is so constructed that it can not be moved by this couple,
then it must be made strong enough to withstand this moment as
well, which is usually considerably larger than the one first mentioned.
On most heavy mounts (tipping parts weighing over 25,000 kilo-

551

grains) the elevating mechanism is arranged so that it can slip slightly
under the action of this couple, the slip-friction device being inserted
ahead of any worm or screw which^ of course, are irreversible. The
movement takes place only after the projectile has left the bore and
does not affect the accuracy of fire. Even in these cases, the gearing
seems to be made strong enough to stand this moment, with a
safety factor of perhaps two. On the sliding moimts, with fixed
trunnions, neither of the above stresses occiu*, but if the center of
gravity of the gun is not exactly coincident with the axis of the trun-
nions, a turning moment develops as the mount recoils. A turning
moment is developed in a similar way with a rolling mount where the
trunnions are very likely to be behind the center of gravity, as on the
British 14-inch mount.

418. Under the above analysis the turning moment to be resisted
is calculated or assumed. With the heavier gims the moment be-
comes more and more difficult to provide for. Ordinarily, one tooth
of a pinion must take it. Next, a second pinion with another rack
may be added. After these, plain worms, Hindley worms, and
screws, give possibilities of progressively increasing strength within
the practicable limits of the mechanism.

419. The efficiency (d) above, required of the gear, depends upon
the work to be done in elevating the gim and the power available.
The work is, in general, that of overcoming the friction of the trim-
nions in their bearings. With the small guns of light weight and sup-
ported by trunnions of small radius this is comparatively insignificant,
but with heavy guns and large diameter trunnions, particularly with
the sliding mounts, where particularly large trunnions are required,
this friction may be considerable. When the work of overcoming
this becomes too large, recoiu*se is had to various antifriction de-
vices, which support the gun diu'ing elevation but give under the
shock of fire and allow the main trimnions to take that shock.
These devices operate either by reducing the coefficient of friction,
as with the roller bearings, or by reducing the relative move-
ment, i. e., using a very small radius auxiliary trimnion (St. Chamond
type). Some devices combine these two ideas, and the arrangement
on the 280-millimeter German mount, plate 388, is perhaps the best
which has been seen. In practice these devices seem to be adopted
almost universally for mounts with tipping weights exceeding 25,000
kilograms. The second factor concerned, as noted above, is the
power available. This is preferably hand power and may be approxi-
mated as varying from one-tenth horsepower, for a man spinning a
handwheel for a short time, to perhaps 1 horsepower for four men
working at top speed on long radius cranks. Some French mounts
have 7^ horsepower electric motors for elevating and the British 14-

552

inch has a 20-30 horsepower gasoline engine. For the sake of sim-
plicity of construction, operation, and maintenance, it is highly de-
sirable that hand power be used where possible, and it is believed that,
if ef&cient gear trains and good antifriction devices are employed, this
is possible even with the heaviest gun; and even where power ele-
vating is used, the hand mechanism should always be provided as
an auxiliary.

420. The required efficiency of the gear train can be approximated
from the preceding considerations. Manifestly, it is a function of the
number and character of the mechanical elements in the train.
These are, usually, spur gears, bevel gears, chains, worms, and screws,
with efficiencies falling off in about the order named. Low pitched
worms and screws are very inefficient. It is, of course, necessary to
make careful calculations on the efficiencies of each individual ele-
vating mechanism but these will always be found to involve two con-
stants which must be assumed, the coefficient of friction in the trun-
nion bearings and the efficiency of the gear train. The relation of
the former divided by the latter is taken as an indication of the effi-
ciency of the mechanism. As an indication of values, data has been
taken from proof tests of a number of seacoast carriages, and the effi-
ciency of the mechanisms has been computed. Itisfoimd tovaryfrom
0.372 to 2.67 with an average of about 1.14. The gear trains of all
these mounts included a worm or a screw and from one to four pairs
of bevel or spur gears. Assuming 0.15 for the coefficient of friction,
this would indicate a gear train efficiency of from 40 down to about
6 per cent. By contrast, the American 16-inch howitzer with a train
of three pairs of spur gears, gives a value of approximately 0.15; that
is, a gear train efficiency of about 60 per cent, with a coefficient of
friction of about 0.10. This indicates clearly the superiority of spur
gears from the standpoint of efficiency. Since the gun of this mount,
the tipping parts of which are at least half as heavy as those of the
largest gun to be considered, can be elevated in 25 seconds by one
man with one hand, it is felt that spur gears give a sufficiently efficient
train so that even the largest gun could be operated through them by
hand power. The best example of this construction is the St. Cha-
mond 340-millimeter gun mount, plate 427, with a gear ratio of
approximately 1/1 and on which the elevating gear is apparently
entirely satisfactory.

421 . In the matter of simplicity, (e) above, manufacture is probably
simplest on chains and spur gears, and becomes progressively more
difficult on bevels, screws, worms, and Hindley worms. As to main-
tenance, the difficulties involved are confined largely to the necessity
for close adjustment. Within limits, practically all that is required
of the chain drive is that the two sprockets be in approximately the

554

same plane. With spiir gears, the distance between shaft centers must
also be fairly closely maintained. With bevel gears the shaft center
lines and planes of the gears must both be exactly maintained. With
worms, the shaft distances and the plane of the worm shaft must
similarly be kept just right, and with Hindley worms, the position of
the worm along its shaft must be exact as well. With the screw,
screw and nut must be coaxial, but if they mesh at all, this con-
dition is assured. This indicates that screws, chains, and spur gears
are the easiest mechanisms to keep in adjustment, and that bevels,
worms, and Hindley worms are more difficult in the order named.

422. The way in which these five requirements are realized may be
understood by a study of the various mounts described in section 3,
Volumes I and 11. Tlie following summary, extracted from section 3,
is given, covering some of the points discussed in the preceding
paragraphs:

Use of slip-friction device: Almost invariable with mounts
whose tipping parts weigh over 25,000 kilograms. Excep-
tions have screw elevating gear.
Use of antifriction device: Almost invariable with mounts
whose tipping parts weigh more than 25,000 kilograxns. The
single exception has a power drive for the elevating gear.
Mechanism at the gun: Forty-one examples classify as follows :

Curved rack and pinion 29

Straight rack and pinion 1

Worm and wheel 3

Screw and nut 8

41
Gea;; train, exclusive of above:

Spur ^ears only 5

Bevel gears only , 6

Spurs and bevels .* 2

Worm and bevel 17

Chains employed 4

General type of entire mechanism:

Rack and spur gears 5

Rack, worm, and bevels, etc 19

The only types of mechanism which occur with almost or iden-
tically the same arrangement of components, on a number of mounts,
are the rack with spur-gear train, which is found only in American
and French designs, and the rack, pinion, worm, wormwheel, and
bevel combination, which is very popular and occurs in American,
French, British, and German designs. The chief objection to 'this
latter type of gear is low efficiency, which has necessitated a low
ratio of gun to handwheel movement — from 0.33/1 to 0.67/1.

555

423. The conclusions with regard to elevating mec^hanism are:

(a) Extent of elevation: To 45-^5 degrees for guns ; 65 degrees

for howitzers.

(b) Ratio of handwheel to gun movement: One to 2 degrees

of gun movement per turn of handwheel.

(c) Strength: Usually safeguarded by a slip-friction device.

In exceptional cases great strength may be obtained by

the use of a screw.
'id) Efficiency: Spur gears most efficient. Screws and worms

may reduce efficiency to very low values.
(e) Simplicity: Spur gears, chains, and screws are simplest

mechanisms. Bevels and worm^ to be avoided when

possible.

424. Tbavebsino Mechanism. — ^Traversing mechanisms are dis-
cussed in a general way in section 1. A detailed discussion of the
mechanical featiires of the different schemes follows.

425. Nontraversing mounts must be pointed in azimuth by some
extraneous means, as a curved epi or a turntable. These mounts
are usually of the rolling or sliding recoil type and have some sort of
translating device to bring them back again into firing position. See
description of recoil mechanisms above. This same mechanism can
be used, of course, to move the gun along the epi for training in
azimuth. In the case of a turntable a special rotating mechanism,
usually motor driven, is, of course, provided in the tiirntable itself,
plate 428.

426. Railway car traverse, as explained in section 1, allows usually
only a very limited movement on the trucks, perhaps 4 degrees. Car
traverse in connection with an emplacement is best worked out
through the use of a center-plate arrangement built into or attached
to the car body; it usually includes roller or ball bearings on which
a part or all of the weight of the car body is supported. All round
fire mounts of the car traversing type, as at present developed (Amer-
ican 14-inch model E, German 380, 280, 240, and 210 millimeter
mounts), require elaborate foundations. Car traverse maybe supe-
rior to top carriage traverse for a wider range of fire than can be
obtained from the trucks, with guns which are not so powerful but
that a rapidly built emplacement is possible, yet which are so large
that top carriage weight is comparable with car body weight. So far
as is indicated by present practice, however, this type of traverse is
best applicable to high-powered guns requiring only limited traverse
in the mount and firing usually from an epi.

427. Top carriage traverse, as noted before, is suited to a maximum
traverse of from 10 to 360 degrees. The top carriage consists usually
of cast-stool side frames carrying the trunnion bearings in which the

gun cradle swings, and transoms connecting the side frames. It will
be more fully discussed later. The components of the traversing
gear should be strong enough to resist the forces tending to rotate the
carriage when the piece is fired at high elevations. The ratio of the
gearing should be such as to allow of fine adjustment — that is, to one
mil. Efficiency is not of as much importance here as in the elevating
gear, except, perhaps, for coast defense work. As previously pointed
out, this type of traverse finds its best application in mounting the
less powerful pieces for all round fire, where carriage weight is small
in proportion to car body weight.

428. A discussion of the relative advantages of these systems of
traverse is narrowed down by the following considerations:

(a) Top carriage traverse is so simple for howitzers and the
smaller guns (8 inches or less) that the other tvpes do
not merit consideration.

(6) Nontraversing carriages have so little advantage in sim-
plicity over the car traversing type that they need not
be considered.

429. The question becomes, therefore, one as to the type of traverse
to be adopted for heavy guns — specifically between epi curve-car
traverse combination and an emplacement top carriage traverse com-
bination. The chief objection to the former is the ease with which
the battery may be located by aerial photography; in other words,
the difficulty of effective camouflage. The answer to this objection
lies chiefly in two considerations; first, that the type of target fired
on from an epi is usually such that the gun is placed, delivers the
required number jof shots, and is then returned from the epi to the
base, so that, even though the enemy may know where all the epis
are, he is by no means sure just where the gun is, and it may quite
easily deliver its fire and retreat before he can be sure of its location
and start counter-battery fire. The second consideration is that
camouflage has proved ineffective against the various means of detec-
tion which have been developed — aerial photography, sound ranging,
flash ranging, earth vibration ranging, etc. The Allies found, after
the conclusion of the war, that the vast majority of the German bat-,
teries had been exactly at the points where these various agents had
indicated them to be. In the special cases known where careful and
effective camouflaging was worth while, for instance for fire of de-
struction against the bridges east of Metz, the mounts were in position
for a long period, but, on the other hand, they were firing at practi-
cally a single target, and needed no epi curve, car traverse being
ample for the service. With top carriage traverse, on the other hand,
ordinarily either no more traverse is realized than with the other type
or a special foundation has to be installed, which, with heavy guns, is
a very difficult and time-consuming job.

558

430. The general conclusions with regard to traversing mecha-
nisms are that two types should be considered for services as follows:

(A) For heaviest cannon (14-inch 50-caUber guns and 16-inch 25-
caliber howitzers) : Top carriage or car traverse as wide as stability
will allow, using outriggers to take most of the horizontal component
of the force of recoil. These same mounts should be so designed as
to be capable of operation as rolling mounts if desired and be equipped
with traversing rollers and a base ring of the 14-inch model E type
for service in coast defense.

(B) For medium-powered cannon (10-inch 50-caliber and 12-inch
25-caliber howitzers) : Car traverse with wide angle of fire, plates 59
and 60.

431. Gun Carriage. — ^Most of the components of the gun carriage
have already been discussed, but there remain to be mentioned some
facts regarding the types and construction of the main frame and the
types and construction of pintle and traversing rollers.

432. The main frame of the carriage consists normally of two side
members which support the trunnion bearings; and connecting tran*
soms and perhaps a racer. In American and early French practice
these parts are uniformly steel castings. Later French and English
practice, however, is to build these parts up out of structural shapes
and plates.

433. Such practice appears entirely satisfactory, providing pro-
vision is made (by additional clearances, etc.) so that the greater
flexibility of the structural, as compared with the cast frames, can not
cause trouble.

434. Pintle and roller arrangements are of two types. The first,
or front pintlQ type, has a large vertical pin under the front of the
carriage, around which the carriage swings. Rollers, usually spring
supported, are provided imder the rear end of the carriage, and these
travel on a special track on the base, or railway car. This type is
exemplified, for instance, in the BatignoUes mounts and the American
16-inch howitzer. The advantages of such a top carriage are com-
paratively small forces on the traversing rollers, due to the relatively
long lever arm at which they act and great simplicity of construction,
faciUtating both original manufacture and field maintenance. The
disadvantage is that the work involved in traversing is large in pro-
portion to the distance between the pintle and rollers, and because of
the large radius of the roller path the type can be used on railway
mounts for limited traverse only. The second, or center pintle type,
is provided with cylindrical pintle (either a pin or a large radius sur-
face) and a complete circle of conical traversing rollers or balls, both
concentric with the carriage. The rollers circulate between conical
paths on the base ring and racer, and constitute a roller bearing; the
balls, varying in diameter from 4 to 8 inches, circulate between two

559

grooved paths of circular cross section on the base ring and racer.
Both rollers and balls take the entire shock of fire directly. The
radius of the roller or ball path is made as small as possible to reduce
the work of traversing. The advantages of this type are that a mini-
mum traversing force is required and that the apparatus is sufficiently
compact to allow all-round fire in the limits of railway clearance. The
disadvantages are the heavy loads which must be carried by the travers-
ing rollers, or balls, and the comparative complexity and exactness
required in fabrication, especially in the case of the rollers.

435. The conclusion from the above is that the center pintle type
would be most usuaUy employed on railway mounts for medium
howitzers and light guns, and for heavy guns and howitzers in con-
nection with some type of separate base ring. The other type will
be employed for heavy howitzers and medium and light guns when a
greater carriage traverse (10 degrees) than can be secured in car
traverse (4 degrees) is desired.

436. Railway Car Body. — ^Railway car bodies are, with the ex-
ception of certain improvised French mounts, always of structural
steel and are of two types, flat car and girder.

437. The car bodies of the first type may be merely flat cars of the
ordinary freight pattern with the carriage mounted on top of them, as
in the case of the 155-millimeter howitzer, plate 429, the 240-millimeter
gun, plate 237, or the 194-millimeter gun, plate 431. This tjrpe is
simple, sturdy, and satisfactory for these mounts.

438. In most cases, however, the height of the gun carriage is such
that headroom demands a drop frame type of flat car body. This
tjirpe is illustrated by the 200-miUimeter howitzer, plate 10, the British
12-inch howitzer, plate 432, and the American 8-inch gun, plate 88.
Experience has shown two defects with this type of flat car body,
one the difficulty of making it stiff enough to prevent undue deflection
under the load of the gun, thus perhaps causing deflection of the gun
carriage base ring and cramping or jamming of the traversing mecha-
nism; and the other is the same as that experienced with commercial
drop frame flat cars, viz, their inability to stand under the severe
buffing strains to which they are subjected in coupUng, and being
hauled over the road, with heavy trains.

439. The girder type of car body is employed when the weights
become too great to be carried on the ordinary flat type. PracticaUy
all of the larger caliber mounts furnish examples of this type. This can,
of course, be made as strong and as stiff as occasion demands. Only
one point needs to be mentioned, and that is the necessity for rigid
cross bracing between the two side girders. The lack of such suffi-
cient bracing results in racking or weaving of the side girders relative
to each other and the binding of the gun trunnions in their supports
breakage of trunnion caps, and the like. There must be actual contact

181768—21 36

563

H
04

564

between the webs of the transoms and the webs of the side girders to
produce the desired rigidity. The rirets can not be depended upon.

440. An experimental car body of reinforced concrete, plate 433,
for a 30-centimeter mortar has bcNen made in France. In spite of the-
fact that it was successful, this type of construction is not thought to
merit consideration where steel is available.

441. Anchorage. — ^The discussion under section 1 brought out
most of the points regarding the existing types of anchorage. They
may be summarized as follows:

(a) Mounts requiring no preparation: Must be of the rolling

recoil type, can have but very limited traverse, and are
in general best suited to the very heavy guns.

(b) Mounts requiring a track platform: Sliding type, suited

for heavy guns with limited fire. Strut type, suitable
for light and medium gims with 60 to 360 degrees trav-
erse.

(c) Mounts requiring a ground platform: Suited for medium

guns with all-round fire, and for heaviest guns with lim-
ited fire. (All-round fire for heavy guns in exceptional
cases.)
Something remains to be said regarding mechanical details and
relative desirability of the different designs under the various types.

442. The first type is, of course, ideal from the standpoint of
anchorage. The chief objection, however, is that in all types here-
tofore constructed it has been necessary to include » recoil system
to reduce the maximum pressure on the trucks, and a counter-
balancing system to compensate for the extreme muzzle prepon-
derance resulting from mounting the trunnions close to the breech
to secure great elevation. Further, the length of recoil along the
track (30 to 50 feet) is too great. Improvements now being experi-
mented with on sliding mounts, and detailed in paragraph below,
suggest that some means might be adopted to transmit the force
directly to the rail instead of through the truck springs. If the car
girder were sufficiently strong to distribute the pressure along the
track for the length of the mount, pressure on the ties would be
nearly as low as on the sleepers of the present sliding mounts, and
the pressure on the ground would be halved. If this arrangement
did not require too great a weight of girder or too great a complica.
tion of jacks it would seem to constitute a most excellent system for
guns requiring only very limited traverse.

443. The sliding type of track platform mount requires an epi
built with special, long, closely spaced ties, and laid with I-beams
in addition to the regular rails. The mount is distinctly^ at a disad-
vantage, as compared with the rolling type of mount, in that stand-
ard track can ordinarily not be utilized and, indeed, no standard

566

track materials, except rails, can be used to advantage in the special
construction required. A modification of the sliding type mount is
now being experimented with, in which the I-beams, or bearing
stringers, are fastened to the mount and slide along the top of the
ties instead of having them fastened to the top of the ties and
allowing the moimt to slide over them. This involves the use of
dressed ties of extra length in laying the epi, but on the other hand,
it avoids the use of a large amoimt of structural material in making
the epi and saves time in its construction. ^ The proving ground
tests show that this construction is satisfactory and it offers a disr-
tinct improvement over the previous types. It would seem that this
scheme might be developed by lengthening the beams carried by the
mount, so that enough ties to take the shock would be covered on
standard track. With such a modification and the addition, perhaps,
of a set of cutters on the mount for surfacing the ties, it would seem
that this type might be adapted to operate as satisfactorily on stand-
ard track as the former type operates on a spur of special construction.
This would have the same advantage as the modified type suggested
above, but would, like it, be limited to heavy guns requiring only
limited traverse. The sliding type of anchorage, as at present de-
veloped, however, still possesses considerable advantages over other
types of platform. While it requires the construction of an elaborate
epi, this can be built while the mount is still far beliind the lines ih
safety, and when it is finished the mount can be run up, fired, and
gotten out again in an absolute minimum of time.

444. The other types of track platform anchorage also employ
stringers of beams laid over the ties, to take the vertical component
of fire, but they employ guys, rail clamps, struts, spades, and floats
to take the horizontal component and prevent overturning. No
difficulty is experienced with taking care of the vertical component
of fire, but serious limitations have developed with the devices em.
ployed to take care of the horizontal component and the overturn-
ing tendency. This limitation is of course most marked in an all-
round fire carriage operating at right angles to the track, and it will
be discussed from that point of view. Rail clamps alone sufficed
on the early 155-millimeter howitzer moimt, when used on standard
gauge track. Horizontal floats, just outside the rails, with jacks
attached to the side of the car and screwed down on them, sufficed
for the 164.7 and 194 millimeter guns. On the 200 millimeter
howitzer it was necessary to place these horizontal floats further out
and mount the jacks on the end of swinging arms. This same scheme
was tried and found inadequate for the American 6-inch seacoast
gun. With the addition of a vertical spade to the float it was tried

567

on the British 9.2-inch mount and cables attached to deadmen had
to be used as a supplement. The next step is the use of struts,
with floats arranged at their ends perpendicular to them and bearing
against a prepared and properly sloped surface on the ground. This
is employed on the American 8-inch gun and 12-inch mortar mounts
and the St. Chamond 240-millimeter mount. These seem to mark
almost the upper limit of the possibilities of track platform anchor-
age for all round fire. It is felt that the American 8-inch scheme is
a better design than the St. Chamond. It is more effective and can
be put in place in one third of the time.

445. Ground platforms, requiring removal of the track and the plac-
ng of special work under it, are of two distinct types — the steel or

concrete emplacement type and the wooden float and strut type.
The former is exemplified in the Batignolles platform, plate 54, for
limited traverse carriages, and in the 280-milUmeter German plat-
form of steel or concrete, plates 55 and 66, and American 14-inch
model E, steel platform, plate 239, for all-round fire. Under this
head come also the tui'ntable emplacements used with the German
380-millimeter, plates 417 to 422, and suggested for United States
coast defenses, plate 428. The latter type noted above, i. e., wooden
float and strut, is merely an extension of the track platform and
strut type of mount. It is illustrated by the St. Chamond mounts,
plates 51 and 52, and the American Navy 14-inch mount M. I,
plate 23. This type allows only of limited traverse. Relative
speed and simplicity of installation give a decided advantage to the
Batignolles type of ground platform for limited traverse carriages,
but the manufacture is, of course, relatively costly and elaborate.

446. A general study of the various types of platforms shows that
the permissible load figured on is approximately two tons per 9quare
foot, or 20,000 kilograms per square meter. General Peigne's early
researches led him to recommend a pressure just half this, i. e.,
10,000 kilograms per square meter, and it is undoubtedly true that
for horizontal thrusts near the surface of the ground, as in the track
platform and strut type of mount, the use of a figure less than
20,000 kilograms is advisable. For vertical stresses or in case of
floats deeply buried, the figure is probably perfectly good.

, 447. Trucks. — The trucks used for railway mounts do not diflfer
from those required for other types of heavy railroad work and no
detailed discussion of merit need be entered into. It may be said,
in brief, that the outside type of journal should be used if at all
possible, for the sake of simplicity, and that both hand and air brakes
should be provided. It should also be added that a number of
peculiarities which will be noticed on French trucks — such as lack of

568

equalizers, mounting the centerpin off center of trucks, etc., are
improvisations, and are not to be considered desirable for this
type of service.

448. Axle loads, during the present war, have been limited by
French railways to 17 metric tons. The American Navy 14-inch
moimt, which exceeded this by about 35 per cent, gave a great deal
of trouble, especially from the overheating and scoring of journals
and bearing brasses. Mounts with rolling recoil take the firing load
directly through the trucks, and this force must be reckoned with
in the design. This force is about 35 long tons on English mounts
and 27 long tons on the American 16-inch howitzer.

449. Ammunition Supply System. — ^The ammunition supply sys-
tem consists of two essential parts, as a rule, a hoisting and translating
mechanism for bringing the shell near the gun and a tray or truck for
guiding it into the breech. The hoisting and translating mechanism
is usually a Triplex block suspended either from a jib crane or an over-
head trolley. The jib crane appears to be the favorite for small cal-
ibers, and for large calibers where the gun lias a fau* amount of
traverse. The overhead trolley, however, is used in most of the heavy
mounts where there is very little traverse, and where the shells can
be taken directly out of the ammimition car, or oflf the transbordeur.

450. The guiding mechanism is a tray onto which the shell is
lowered, and which extends into the breech of the gun. On some
mounts, as the American 8-inch gun, this is very small and is carried
by a second jib crane. Usually, however, a part of it constitutes
the top of a stationary shell stand, while another portion can be
pushed into the breech when the latter is opened. The shell is then
slid along it into the gun, plate 161. Another type consists of a tray
provided with wheels, which rolls along a track and part way into
the breech of the gun. The tray then brings up against a buffer,
while the shell continues to move of its own inertia and comes up to
a full or partial seating against the forcing cone. Here. the same
line of demarkation occurs as in the lifting mechanisms — the plain
tray appears to be the favorite for all light shells, and for heavy
mounts with considerable traverse. In many cases a negative loading
angle Is given to assist in moving the shell into the gun. The rolling
tray or shot truck is more used with the heavier calibers and mounts
having small traverse, plate 162.

451. It is felt that the above indicates the best use of the various
arrangements discussed, i. e., "the crane and tray arrangement for
practically all small guns and the overhead or trolley cranes and
shot truck arrangement for heavier caliber guns having very small
traverse.

452. Special ArranoeXients for Coast Defense. — As noted at
the end of section 2, the use of railway mounts for coast defense calls

569

for special characteristics not demanded in land service, viz., provision
for operating the sighting, elevating, and traversing mechanisms up
to the moment the piece is fired, so that a moving target can be fol-
lowed and also for operating them simultaneously for the entire
battery for volley firing. It is proposed here to discuss the merits
of the several possible arrangements for accomplishing this end.

453. The diflficulty encountered in ther evident solution of leaving
men on the mount to carry on these operations is that, in rolling and
sliding mounts, and quite probably in all mounts with any but the
heaviest anchor^e, the shock of fire is so great that this has never
been felt to be safe.

454. For the purposes of this discussion, mounts may be divided
into three classes:

(a) Heavy mounts with top carriage traverse arid operating

fixed to the anchorage.

(b) Light mounts with top carriage traverse and operatirg

fixed to the anchorage.

(c) Sliding and rolling mounts traversing by movement alorg

curved epis.

455. With heavy mounts fixed to an anchorage, it is felt that the
evident solution mentioned above, of leaving the personnel on the
mount, is feasible. This same condition may be realized with heavy
guns with small traverse, by mounting them on a turntable, plate 428,
which would be electrically operated. The latter arrangement has the
disadvantage that turntables must be provided wherever firing is to
take place, and the former would seem to be feasible only when an
elaborate anchorage is employed. With either of these arrange-
ments, however, the guns can be controlled and fired just as if thev
were installed in a fort in the ordinary wa\-.

456. With light moimts fixed to an anchorage, the vibration of
the structiu'e from the shock of fire would probably be too great to
permit the personnel to remain upon it. Three arrangements suggest
themselves as possible solutions for this case.

(a) Remote control of elevating and traversing mechanism
either mechanical or electrical, and observation of
azimuth circle and elevation indicator through tele-
scopes. In this case the azimuth circle should be
rotatable, so that correction of zero could be made
after each shot. For the case where the target is ob-
served directly prism telescopes would have to be
employed and arranged as shown in the sketch, plate
434, so that their eyepieces, rotatable around the center
of carriage rotation, would be so connected with the
traversing mechanism as always to point in the same
direction.

equal!
impT

7t

:^ro

571

(b) Provision of a simple recoil mechanism on all seats occu-

pied by personnel during firing. The shock and vibra-
tion in these moimts is very sudden but not of great
amplitude y so that this cushioning mechanism would be
very simple. It would, of course, be essential that all
optical instruments be arranged so that the eyepiece
recoiled away from the observer.

(c) Provision of concrete foundations to which the car can

be firmly fixed. This is the Luellen idea and would, of
course, be equivalent to a gun moimted on a permanent
emplacement.

457. The first scheme (a) above is quite feasible but somewhat
complicated, the third has the disadvantage that fire can only take
place at prearranged points, and the second seems best if it can be
worked out satisfactorily.

458. With sliding or rolling mounts operating on curved epis, two
alternatives are possible:

{A) The pointer may be located on the ground, with remote

control arrangements for elevation and traverse.
(B) The pointer may be located on the mount and his seat
provided with a long recoil mechanism, such that the
shock of fire will not injure him.
In either case somewhat elaborate apparatus for laying the piece
is required. The aiming point may be located at the center of the
epi or at some other point. In order to show what may be done,
the following four cases will be discussed.

(a) Pointer on ground, reference point at center of epi.

(b) Pointer on groimd, reference point anywhere.

(c) Pointer on mount, reference point at center of epi.

(d) Pointer on mount, reference point anywhere.

459. Case (A) is illustrated in plate 435A. A mirror is so fixed
on the mount that its plane is always parallel to the vertical plane
through the center line of the gun. (If the mirror is tilted up to
raise the line of sight, so that it moves in a cone instead of a plane,
the following reasoning ^ still holds. This may be necessary with a
group of mounts controlled from a tower.) At the center of the
epi the pointer is located on a platform rotatable about that center.
He looks through a telescope A, whose angle 6 with the baseline
can be varied by rotating the platform and can.be read on an azi-
muth circle. His line of sight is turned at right angles by means
of the prism P, which can be moved back, and forth for a distance
of perhaps 10 inches each side of the center along the line of sight
of the telescope. The operation of training then is as follows:
The telescope and rotatable platform are set, either by an assistant

' from telephone instructions or automatically through mechanical

572

PiJ^.TE 435A

3LWJN6 /9A//? /rOLUN6 /f/fJLWAY Mai//^T5

f^»

C/f3E '/9

573

or electrical synchronizing from a central observation point, so
that the angle a equals the required deflection of the gun from the
base line. The pointer sets his prism directly over the center of
the platform (in mid-position), and by operating the controllers
of the electric translating motors on the mount he brings it up until
he sees the reflection of the prism (or a pointer arranged on it) in
the mirror of the mount and registering with the vertical cross hair
of his telescope. This would mean that both angles B and C are
right angles, and therefore that angle 8 equals angle a the required
deflection.

460. Due to the irregularities of the track and the following of
the mount upon it, the line AB may not always pass exactly through
the center point. In such cases the prism may be slid back and
forth until this line passes through it.

461. This scheme may be greatly simplified if the observer of the
targets is placed in a tower just above A, and arrangements are made
so that his telescope and the telescope and platform shown here
rotate together. The services of the man setting the azimuth circle
at A would then be unnecessary. In actual practice, however, it
will likely be found more desirable to place the observer's tower on
high ground at some distance from the crenter of the epi, which will
be in low positions not visible from the sea.

462. Case (B) is illustrated on plate 435B. A horizontal azimuth
circle and a rod marking its vertical center line are mounted on the
gun, so that the rod and the zero of the circle are both in the vertical
plane through the axis of the gun. At any point whatever, as A, the
pointer is located on a rotable platform with a telescope. Attached
to this telescope, and so arranged that it occupies half of the field of
view of the latter, is an independently rotable azimuth circle, which
can be read against the cross hair through the telescope, and also
against the base line at h. The operation of training is then as
follows: The circle -4 is rotated either by an assistant from telephoned
instructions, from the observation tower, or automatically through
mechanical or electrical sychronizing, from a central oj^servation
point. The pointer keeps his telescope trained on the central rod of
the azimuth circle on the mount. He then traverses the mount,
through remote electrical control, until the reading of the azimuth
circle on the mount against the telescope cross hair is the same as
the reading of the azimuth circle at A against the same cross hair.
Each of these circles occupies half of the field of the telescope, so
that his task is simple to bring like graduations opposite. Now, if
the circle at A is always kept with the required angle reading at 6,
then the reading on the circle by the telescope will be required
angle + a. It B is made equal to this, then by constructing 5 will
equal the required angle.

574

Plate 435B

^r vi:

F/RE CONT/^OL

ji/o/A/a ^No MLL/r^s /f/fiLw/ir /^oi/Afrs

C0/I5T i>EFENS£,
C/9SE "3"

575

463. Case (0) ia illustrated on plate 435C. A telescope with a
movable prism, similar to that described under case (A), is mounted
on the mount so that it is always parallel to the vertical plane through
the gun center line. At A, the center of the epi, a rod and azimuth
circle are moimted. The 90-degree graduation of the azimuth circle
is placed at b on the base line with the graduations decreasing in a
clockwise direction. The operation of training is then as follows : The
pointer is given the required angle by telephone, or an index on the
azimuth circle is moved to it, by an assistant or by automatic
mechanical or electrical synchronizing arrangements from a central
observation point. The pointer, looking through his telescope, moves
his prism to bhng the central rod of the azimuth circle on the vertical
cross hair. He then traverses the moimt until his cross hair inter-
sects the desired graduation or the index on the azimuth circle.
The required angle, as set off, is that between AC and AB. This is
evidently equal to angle d by geometry.

464. Case (D) is illustrated on plate 435D. On the moimt are
located an azimuth circle and rod, similar to that described for
case (B), and a telescope, rotable about the vertical axis of this circle.
At any point, A, there is located another telescope and azimuth circle,
simUar to that used at ^, iii case (B), except that it reads the gradua-
tion on its own azimuth circle corresponding to the intersection with
base line, as a h, rather than that corresponding with intersection
with telescope line of sight, as in the previous case. This azimuth
circle is rotable independently of the telescope and its graduations
rise in a counterclockwise direction. The operation is then as
follows: An index is set on the graduation of the azimuth circle A
at the graduation corresponding to the desired deflection from the
base line. This may be done automatically as before, or the deflec-
tion may be telephoned to the pointer instead. The assistant at the
A telescope trains this instrument on the rod on the mount and gets
the reading on the azimuth circle B. He then turns the azimuth
circle A until this same reading appears at a. The pointer at B
trains his telescope on the azimuth circle A and translates his mount
till his cross hair intersects the index or the required angular gradua-
tion on azimuth circle A. From the geometrical construction it is
seen that 8 equals B — a or the required angle of deflection.

465. Of these various schemes, it is felt that (C) is probably the
best and (D) the most complicated in operation. (G) would allow
mounting a battery of guns on concentric epis and training them
from a single point, which might be in the base of a high observsr-
tion tower, and which would lend itself admirably to the arrangement
for mechanical synchronizing of indices, as suggested. This would
be accomplished by having these indices rotated by the same vertical

181768—21 37

576

Plate 4S5G

d<^

<!^S^

■/^ J

\

\ \

/ / \

>.^

F/ZTjE^ coa/t/tol

n?/^

3l/l>//V(P /fA/O /rOLUA/C /frNOC//VT^

f'O/^

CO/95T PrF£A/^£,

C/fSE- ^."

577

Ftjlte 435D

/30* c/frck£

r//ff COA/T/fOL

3UP/N6 /f/vp mtuNif /F/9/1 w/fr /ioarrrs fo/^

COAST P£F£NS£.

C/f5£ "a

578

shaft which carried the observation telescope through which the
target was being followed. Plate 436 gives a rough sketch of such a
scheme.

466. Discussion. — ^The various design details just discussed are so
closely interrelated that it is seldom possible to realize an advantage
in respect to one of them without a corresponding sacrifice in respect
to another. The following tabulation is given of examples drawn
from practice to illustrate this interrelation :

Point gained.

Point sacrificed.

Cradle recoil (easy anchorage;

rapid fire).
Slidmg recoil (simple construction,

little maintenance).
Rolling recoil (no anchorage)

High elevation (long range)

Rapid elevation (rapid fire)

Efficient elevating gear (easy oper-
ation).

Nontraversing (simple construc-
Uon).

Car traversing (accuracy of laying).

Top-carriage traverse (accuracy of
laying: ability to shift targets).

No anchorage (rapid emplace-
ment).

Track platform (fairly rapid em-
placemrait; all round fire; rapid
fire).

Ground platform (wide traverse
on heavy guns; rapid fire).

Simplicity and rapidity of manu-
facture; small maintenance.

Rapid construction of emplace-
ment; rapid fire. (Small guns.)

Same as cradle recoil; rapid fire;
minimum number axles.

Balanced gun; gun without
counterwdght or counterbal-
ance.

Simple trunnions; easy operation .

Compactness of gear; sdf-lockhig
gear.

Rapid construction of emplace-
ment; acciuacy of laying.

Wide traverse; rapid emplace-
ment.

Simple construction

Example.

Rapid fire; simple construction

of mount.
Utmost rapidity of emplacement;

simple construction of mount.

Rapidity of emplacement; simple
construction of mount.

St. Chamond and BatignoUes

mounts.
Schneider mounts.

Armstrong 12 and 14 Inch and 14
and 16 inch American mounts.

Armstrong 14-inch, American 12
and 14 inch.

St. diamond 400-millimeter.
St. Chamond 400-millimeter.

Schneider mounts.

Armstrong 14-inch; German 280-
millimeter.
American 8-inch mount.

American 16-inch.

American 8-inch.

St. Chamond 400-millimeter.

467. For every class of service, therefore, those characteristics
must be chosen which possess the maximimi number of points ad-
vantageous for the particular service and the minimum nimiber of
points which are disadvantageous.

SERVICE REQUIRED OF RAILWAY ARTILLERY.

^ 468. Guns. — ^In a broad way, the service required of railway
artillery may be defined in terms of caliber and range. Referring
to plate 58 and the discussion of it at the end of section 2, it appears
that the field here discussed lies between calibers of 200 and 500
millimeters and ranges of 10 to 50 kilometers. A single type of gun,
of the largest caliber and longest range required would, of course,
cover the entire field, but this would manifestly be imeconomical.
The subdivisions which should be made in range and in caliber will
be considered in the next section.

469. Subdivision by Range. — ^As noted above, the range to be
covered by railway guns extends from 10 to 50 kilometers. The
distances at which the guns will be located behind the lines will vary

579

Plate 436

.^•^

•Htr

ELEVATION

^PLAN

riRE COt^TROL
FOR-
SLiPING AND ROLLINGS FAILY/AY /ARTILLERY
FOR COAST DEFENSk

SVGGESTEJ? ARRAN6EMENT OF CONCEHTRlC EFl$ ,
FOR CONTROL OF ENTIRE BArTERY FROfA
CENTRAL Og5ERVATI0N TOWER

580

greatly; approximates from practice are given in the table below.
The question to be investigated is how many diflFerent caliber
lengths of gims should be provided for each caliber. The theoretical
points covering this will first be brought out and they will then be
compared with experience.

470. The ideal aimed at in this subdivision is, of coiu^e, to hit
each of the individual targets which may be presented at any point
in the field above, with a minimum average cost per shot. At a
given caliber the cost of charge does not vary greatly with the range.
The cost of gun wear varies enormously and it is this factor alone
which will be considered.

Characteristics of heavy and railway artillery.

HOWITZEB.

8-inch British Mk. 6.

9^inchMk.2

240-ziiin

12-ixich, 2(><;al

16-inch, 18<»d

OUN.

166 0. P. F....
194 0. P. F....
10-inch, 50-caI.
14-inch, 50-ca].

Tyx)e of
carriage.

Caterpillar.

do

do

R.R

do

Caterpillar,

do

R.R

do

Aver-

age

Trav-

dist-

erse

ance

desired.

behind

front

lines.

Deg.

Km.

360

4

360

4

360

4

360

10

10

10

360

5

360

5

60

10

5

10

Maxi-
mum
range.

Km,
10
12
16

ao
ao

17
25
35
45

Effec-

Uve

range

behind

enemy

lines.

Km,

6

8

11

10

10

12
20
25
35

Weight

projec-

tUe.

Weight
explo-
sive

charge.

Lbs.

IAm.

200

20

200

34

356

. 40

700

100

1,600

235

05

«2

176

32

510

65

1,200

181

life of
gun.

roonds
full

charge.

6,500
3,700
2,800
1,000
6S0

4,500

2,000

620

360

471. Consideration of a large number of actual cases shows that
the cost per shot for gun wear varies with the maximum range at
which the gun can shoot. These cases as well as theoretical calcu-
lations show that the variation in cost per shot is directly as about
the cube of the range. On the basis of the above it can be shown
that two guns, one having 100 per cent and the other from 70 to 80
per cent of the maximum required range, constitute probably the
most advantageous subdivision to cover the above field. A study
of the caliber length of the entire existing line of the United States
Army cannon indicates a decided grouping around average caliber
lengths of 12, 32, and 50. This corresponds approximately to ranges
of 100, 75, and 45 per cent. This may be taken as a rough check
on the above, because the variation in range covered by these guns is
greater than that in question here.

472. Subdivision by Calibers. — As noted before, calibers of
pieces are determined by resistance of targets; but there are targets

581

of two kinds as regards resistance, and these require separate con-
sideration . They are :

(a) Targets which* require only a certain amount of explosive
to destroy them; i. e., which may be demolished by a
few large or many small shells.
(6) Targets requiring at least a given caUber shell on which a
larger caliber represents a waste and a smaller is in-
effective.

473. A detailed investigation of the ranges, weights, and rounds
life of existing guns indicates that for targets of type (a) the cost in
gun wear of placing a given weight of projectiles is nearly independent
of caliber for ranges above 20 kilometers. (Details of these calcula-
tions are given in Appendix II ; in such cases hence, subdivision of
calibers is of relatively small importance.) For ranges of 20 kilometers
or less it becomes progressively more economical to use the smallest
possible cahber, sending over the required larger number of shells to
accomplish the demohtion.

474. For targets of type (b) the above investigation indicates
that the cost per shot in gun wear varies as about the caUber cubed,
and the laws* governing the most advantageous subdivision would be
similar to those deduced in the case of range.

475. In land warfare it may be said that the targets of type (a)
occur at ranges (over 20 kilometers total or more than 10 kilometers
behind the lines) and under circumstances for which guns are em-
ployed (interdiction, long-range destruction of buildings, railroad
yards, store yards, etc.); while targets of type (6) (fortified works,
troop shelters, etc.) are generally fairly close and often demand a
plunging fire, thus requiring Howitzers. Hence it may be concluded

that:

(a) Great subdivision as to calibers is not called for theo-
retically for guDS. Here such subdivision would
probably be decided wholly on the basis of other con-
siderations, such as strength of given types of mounts,
relative range, etc.

(6) Howitzers, however, should be well subdivided, probably
with three sizes between the limits given. A subdivision
of 400 millimeters or 16 inches, 305 millimeters or 12
inches, 240 millimeters or 9.2 inches, checks well with
theoretical requirements. The latter Howitzer will
probably be mounted upon a caterpillar and need not
be considered here.

476. In coast defense, targets are practically all of class (&), para-
graph 472. Of necessity, plunging fire will be conducted at shorter

582

ranges than> direct fire; those targets requiring the largest caUbers,
however, will generally also be at the greatest ranges.

477. SuBDiYisiON Based on Requibements of Service. — ^In the
spring of 1918 the allied armies were planning a great offensive for
the year following and elaborate consideration was given to heavy
artillery requirements. The following condensed tabulation is based
on the report of the allied conference on this subject.

FOB DESTRUCTION.

Oallber reqolred.

Range
required.

Traverse required.

Timefdr
prepaiatioii.

MO millimften

JTm.

18

40
22

rrjmifMi

Ifinlmfim.

400 mi IlimHera

nil

Do.

370 millimeten

Do.

340 mll]lmftt4»n

Immaterial.

IM milUmeteni

Not too knuE.

FOR COUNTERBAT

TERY WORK.

240 nf niiTn^ten

22

22

A-U round .,....,--,-,,-.,,...

iritiltnii-m.

320 millimeters

do

Do.

4

FOR INTERDICTION.

340 milllmAtAnf

36
30

All round

Mfnlmnm.

164 millimeter* .

do

Do.

The railway guns in other armies also give some information along
this line. Some of these are as follows:

CaUber.

Caliber
length,
maxi-
mum.

35

17.3

45

40

45

Range.

Traverse.

Time for preparation.

232 mtlHmeters

Km.
16.7
13.1
24.7
-23.1
31.0

Deg.

360 FairlT small.

305 millimeters

360

20

2

Do.

232 millimeters

No preparaticn.
Do.

306 millimeters

M6 minin»«te»*s- - - - - -

4

Do.

The German railway mounts were:

Caliber.

170 millimeters
210 millimeters
240 millimeters
280 millimeters
380 millimeters

Caliber
length,
maxi-
mum.

40
45
MO
40
45

Range. ' Traverse. ' Time for preparation .

Km.
26.0
26.4
23.1'

7

Deg

27.
26.
55.

2 (17')

or "

50*)

26 10 minutes.
95 I 2-4 days.
40 10 minutes.
40 3-6da3rs.
Epi. No preparation.
360 3 weeks.

> A. 30«aliber howitser is also mounted on this same carriage.

583

It will be noted that this list includes no mortars or howitzers.
The German mortars and howitzers, even up to the largest calibers
(420 millimeters), were generally arranged for wheel transportation.
The one exception is the 420-millimeter mortar mentioned in the
historical introduction. As, however, it has not been possible to
obtain really authoritative information on this piece, it is not in-
cluded above.

478. A further point can be brought out regarding maximum
caliber. Only two 520-millimeter howitzers were made, neither
of which was ever used on the front. The Germans, it is understood,
experimented with a 540-millimeter howitzer, but it was not satis-
factory. Both of these facts point to about 400 millimeters or 16
inches as the* practical maximum caliber.

479. For coast defense, general conditions will not be outlined,
but some idea of the calibers and ranges desired can be gained from
the following table showing calibers of mortars, howitzers, and guns
now in or contemplated for the coast defenses.

CANNON.

MORTARS.

10 Inches.
12 inches.

12 inches.
16 inches.

CaUber

CaHb«r
length, max-
imum for
each caliber.

Muuie
velocity.

10
10

1.150
1,500

HOWITZERS.

20
18

Approximate

range at

maxtmom

elevation

allowed by

carriage.

1,050
1,900

km.

0.9
14.0

2ao

20.6

GUNS.

2 24 inches..

3 00 inches..,
4.00 inches..
4.72 inches. . .
5.00 inches.,.
6.00 inches. . .
7.00 inches. .
8.00 inches. . .

10 inches

12 Inches

14 inches

16 inches

18 inches

50

55

40

48.92

50

50

36.6

50

40

50

42.70

50

42.667

?,400
?,«»
2,300
2,600
2,600
2,600
2,700
3,350
2,250
3,200
2,800
2,700

7.0

8.0

8.1

10.3

9.6

10.8

15.6

29.2

11.2

32.0

38.0

584

Judging from the above, it would seem that almost anything
suitable for land warfare would also find a useful place in the coast-
defense armament.

480. Conclusions as to Guns. — ^The conclusion as to the caliber
and length of guns which should be adopted for a railway artillery
program should be based upon the foregoing considerations and also
upon a comparison with the pieces of heavy mobile artillery which
cover the field inmiediately below.

481. In making this last comparison, account must be taken of the
fact that mobile artillery, especially the pieces moimted on caterpil-
lars, can be taken much nearer the front line than railway artillery; to
bring this out, a tabulation of^characteristics for some heavy wheeled,
caterpillar-moimted and railroad guns, is given on page 602. On the
basis of this data, another curve similar to plate 58 has been drawn,
but this time with abscissae representing the distance of the target
from the front lines. On this, the field covered by each of the
guns, also trench artillery and bombing planes, is indicated, plate 437.

482. In view of all of the foregoing, the following is felt to be a
logical selection of guns for a railway artillery program :

12-inch 20 to 25 caliber howitzer for destniction and counter-
battery work.

16-inch 18 to 25 caliber Howitzer for destruction.

10-inch 50-caliber gun for destruction and interdiction.

14-inch 50-caliber gun for distant destruction.
The fields of these guns have been plotted on the curve, plate 437.
It will be noted that the subdivision, in general, follows the require-
ments of the theory before outlined, except for guns of intermediate
range between the 14-inch 50-caliber and the 16-inch howitzer, and
the 10-inch 50-caliber gun and the 12-inch howitzer. In these cases,
it is felt that most targets, existing at ranges of more than 10 kilo-
meters from the lines, will be of the type which can perfectly well
be handled by a sufficient number of smaller shells (10-inch instead
of 14-inch and 194-millimeter instead of 10-inch), so that occasions
for using the 10-inch and 14-inch guns at short ranges ought to be
rare. It is telt that these guns are also well suited to coast defense.

483. Mounts. — In section 2 it was brought out that types of
mounts (considered on the basis of traverse and anchorage) were
assigned according to the number of different targets to be fired
upon (amount of traverse required) and the time available for the
preparation of emplacement. Other characteristics, as extent of
elevation, are determined by the type and size of gun to be moimted.
A consideration of the report of the allied conference and of general

586

practice in the French and British armies shows these requirements
to be as follows (these points have already been partially brought
out in section 2):

(a) For heavy destruction at short range:

Traverse: It is seldom that more than one target
^ need be covered at a time and limited traverse,

10-12 degrees, appears to be satisfactory.
Time for emplacements: These guns often must work
close to the front line. It is highly important tliat
they advance, deliver their fire, and retire as quickly
as possible. Time for emplacement should therefore
be as small as is practicable.
(6) For destruction at long range:

Traverse: As above, but 2 degrees is sufficient.
Time for emplacement: Abundant leisure is usually
available for construction of emplacement of this
class.

(c) For counter-battery work:

Traverse: 360 d^rees if possible; 60 degrees as a
minimum.

Time for emplacement: These pieces must be even
more mobile than those for destruction at short
range. Time for emplacement should be the mini-
mum consistent with the abo^e traverse (one or
two hours).

(d) For interdiction:

Traverse: Practice in the armies indicates that
limited fire with a fair amount of traverse (60
degrees) is sufficient for railway mounts. This is
further justified by the probability that smaller
mobile guns on caterpillar mounts will cover the
field for which all round fire railway mounts would
be required.

Time for emplacement: This should be the minimum
consistent with obtaining the traverse required.

(e) For seacoast defense:

Traverse: Field of fire 60-180° perpendicular to track.
Must be possible to sight, traverse, and elevate the
mount up to the moment of fire. It must be possi-
ble to do this for a battery simultaneously. This
will probably involve much auxiliary equipment.

Time for emplacement: Should be fairly short.

587

CONCLUSIONS AS TO MOUNTS.

484. Appropriate mounts for each of the guns decided upon, both
for land service and coast defense, will next be considered, and the
various characteristics which the services demand of it, will be
tabulated.

485. Twelve-Inch, 25-Palibeu Howitzer. — A mount of the
general design of either {a) the 12-inch howitzer mount No. 8, or (6)
the 10-inch, is recommended. The desirable characteristics for the
services of counter-battery work and destruction, which this design
should possess, gun mount plates 59, 60, and 438 to 448 are, for
each of the design details:

Recoil: Cradle, with pneumatic recuperator.

Spur gearing with anti-friction device on the trunnions.

Elevation :

Ratio about 2 degrees elevation of gun per turn of hand-

wheel.
Elevation to 65 degrees.
Traverse: Top carriage, center pintle type, with all round fire.
Railway car: Drop frame flat car type, but strongly reen-

forced.
Anchorage: Track platform and struts, like American 8-inch.
Ammunition supply: Crane and tray.

For seacoast defense, recoil mechanism or shock absorbers for
' seats of personnel should be added.

486. Sixteen-Inch, 25-Caliber Howitzer. —This mount is for
fire of dei^truction only. It is felt that a combination of the top
carriage of the 16-inch howitzer, model 1918, MI, the struts of the
12-inch howitzer, the base ring and steel sliding shoes of the 14-inch
model E, and certain rolling recoil features fulfills the requirements
in respect to time for emplacement, wide angle of fire, and adapta-
bility for coast defense. The following detailed characteristics
should be included:

Recoil: Cradle, with pneumatic recuperator.

Spur gearing with anti-friction device on the trunnions.

Elevation:

Ratio, 1.5 degrees elevation per turn of handwheel.

Elevation to 65 degrees.
Traverse: Top carriage traverse, limited fire, 8 to 10 degrees.
(Electrical translating motors for counter-recoil and training
on an epi).
Railway car: Girder type.

Anchorage: (a) Rolling, Qi) strut, (c) base ring.
Ammunition supply: Crane and shot truck.

588

Recoil mechanism or shock absorbers for seats of personnel
and air brakes set by the recoil might well be added, so that
the mount might be used either as an emplacement (base
ring) or as a roUing recoil mount for coast defense, if the
latter method were found necessary.

487. Ten-Inch, 60-Caliber Gun. — This mount must supplement
the long guns on caterpillars on interdiction and long-range^ destruc-
tion work. It must be capable of quick emplacement, should have
a wide field of fire and should be able to deliver a number of shots in
a minimum of time. A consideration of these points leads to the
following recommendations on desirable characteristics:

Recoil: Cradle, with pneumatic recuperator.
Spur gearing with anti-friction device on the trunnions.
Elevation:

Ratio, 1 degree elevation per turn of handwheel.
Elevation to 45 degrees.
Traverse: Car traverse:

On trucks for limited fire of 11 degrees.
On center pintle for limited fire of 60 degrees.
Railway car: Girder type.
Anchorage:

Rolling for 11 degrees fire.
Track platform and struts for 60 degrees fire.
Ammunition supply: Crane and shot truck.
Plates 59, 60, and 438 to 448 show how this design might be worked
up. While details have not been investigated, enough has been done -
on each important feature to demonstrate that nothing is required
r of it beyond that required of a similar feature on an existing suc-
cessful mount. It is believed that this type of mount would be well
adapted to emergency coast defense.

488. Fourteen-Inch, 50-Caliber Gun. — This mount will be used
for the longest range destruction work. It will, in general, be
employed some distance back of the lines, ample time will be avail-
able for placing it and its field of fire at any time is apt to be narrow.
It is recommended that the carriage suggested for the 16-inch, 25-
caUber howitzer be used likewise for this gun. An elevation of at
least 50 degrees and an elevating gear ratio of 0.5 degrees per turn
of the handwheel is recommended.

589

H
H

i

a H

^)

lis:
iiil

- rs

-

'K

w „

w

n

TT"

4

r ^

0

\

!

§1

o

0.
0
N

i

f ■ i

3

fe

i

1

__i

181768—21 38

592

597

SECTION 5.
PROCEDURE IN PREPARING FOR ACTION IN LAND WARFARE.

489. In brief and in effect the procedure in preparing batteries or
groups of railway artillery for action is as follows:

490. The commander of the heavy artillery receives instructions
to operate on a certain group of targets in any of the sectors covered
by the various armies. (This of course is based on the assumption
that all the heavy artillery is available for use in any of the armies."^
In the event that the heavy artillery be divided into imits. a unit being
allowed to each army, then the commander of the heavy artillery
assigned to any given army will receive his instructions from the
commander of that army.

491. The targets in the group as.^igned may be any of the great
variety noted under the heading, "Scope of utility of railway
artillery." The significant point is that they are always of the type
that may be termed "fixed," in the sense that they can not be
moved, or are not likely to be moved, in a short time. This makes
it possible to prepare for an action in a thorough and accurate manner,
and with comparative deliberation. As given in the instructions
to the heavy-artillery commander, the targets are in terms of coordi-
nates with reference to the adopted system of quadrillage. When
given in such coordinates they may be readily located on any
military map and the necessary firing positions selected and prepared.

492. The orders mentioned above are transmitted to the artillery
officer, likely a colonel, directly in charge in the sector concerned,
who, after consideration of the characteristics of the targets and the
probable operating conditions, decides upon the type of artillery
required, and places a request with headquarters that a certain
number of groups of railway artillery of the desired caliber be
ordered to report in that sector for service. The staflF of this officer
further carries out the work of reconnaissance, selecting the firing
position, terrestrial observation posts, and parking stations for the
troop trains. The orienteur officer in charge attached to the staff
proceeds with the work of preparing the necessary data for laying
out the epi curves, etc.

493. Upon receipt of orders from the railway artillery head-
quarters the group commanders proceed with their troop trains to
the sector designated and report to the officer in charge. The troop

(601) ,

602

trains are parked in prearranged places and the personnel of the
various batteries at once proceed with the work of laying all nec-
essary telephone lines, constructing epis, dugouts, etc. When all
preparations to the minutest details have been completed, the
group commander orders the portion of his personnel still at the
artillery camp to proceed to the front with the guns. Each gun,
with its attendant ammunition cars, is provided with its own loco-
motive. It is desirable always to have the guns arrive during the
night and placed on the firing positions so that firing may begin as
soon as it is light enough for satisfactory observation. This observa-
tion may be either from terrestrial posts or from the air; if ter-
restrial, it is desired to have three posts. It is desired to have the
observation handled by airplanes, if at all possible, inasmuch as
they are able to make their observations approximately over the
targets.

494. If necessary or desii:able, the guns may remain in one position
for several days, since it may take the enemy four or five days or
even longer to locate them and place artillery of sufRcient range to
return fire. Generally it is not necessary to remain in one position
very long. In one of the engagements in which the Americans,
operating 320-millimeter howitzers, were engaged, one battery fired
11 shots and the other 45 shots. The targets were demolished and
the battery moved out at night and returned to camp about 30 mUes
behind the lines. They remained in camp until needed at the front
again for similar service.

495. The understanding that at first prevailed in the Ordnance
Department that the various units of railway artillery would be
kept in the field, as the term is used with reference to light artillery,
proved erroneous. This artillery may occasionally be idle for months
and when needed it may be for only a few days, after which it is
moved back to the permanent camp. Incidentally, the shops for
the maintenance of this artillery are likewise located in the- per-
manent camp.

496. Construction. — As indicated in the preceding, considerable
construction of various kinds is necessary in preparation for the use
of railway artillery. This is described and specified very completely
in the instructions for ^'Trackwork for Heavy Artillery,'' issued by
the French Army. This manual is so good a treatise on the subject
that it is quoted entire at the close of this section.

497. Camouflage. — The subject of camouflage is too broad to be
more than touched upon here, but it will be outlined by indicating
first the means developed for locating batteries, and on the other
hand, the steps taken to defeat these means and hide the positions.
In general, camouflage is of less importance, relatively, on railway
artillery than on the lighter pieces.

603

498. Gun positions are located by:

Ordinary observation from —
Advance posts.
Balloons.
Airplanes.
Aerial photography.
Ranging by flash of guns.
Ranging by sound of guns.
Ranging by earth vibrations from fire.
It is understood that the French have learned, through captured
documents^ that the Germans were, in many cases, able to obtain
almost complete information as to French battery locations by
these means. The French, on the other hand, found when the
Germans were driven back in certain regions, that the German
batteries they had previously located by these methods, were cor-
rectly located, and represented in one instance 27 out of 30 of the
batteries in the region studied.

499. The chief scheme used to camouflage railway mounts and
positions are, first, and most effective, the choice of a protected
position, in a wood or a ravine. Next, the careful concealment of
all approaching tracks and all preparations. Then the use of painted
paulins, tree branches and raflia nets, plates 449 and 451, as well
as the camouflage painting of the mount itself, plate 174. Perhaps
one of the most effective schemes was the interchange of gun posi-
tions and, of course, as previously brought out, the removal of the
railway mount before suitable counterbattery fire could be brought
into play.

500. In view of the great accuracy of the various locating methods
successful concealment for long periods is almost impossible, and
more reliance is to be placed on delivering the necessary shots and
then getting away rapidly.

501. The most elaborate known attempt at concealment is the
emplacement installed at Pont-a-Mousson between Nancy and Metz;
plates 452 to 456. The concrete roof is about 2 meters thick with
several meters of earth above. The gun was fired through a hole
in the roof, as can be seen from the photograph. There was never
any indication that the Germans ever located this battery, though
their observation planes were seen above it while the gun was firing
on a bridge just west of Metz on the first two days of the St. Mihiel
offensive.

502. In another instance, a railway mount was located in the
bottom of a very steep and wooded valley, and fired through a tun-
nel dug through the hill in front of it. This position was never
located by the Germans so far as is known.

604

ENTRANCE TO (-ONCRETE SHELTER TO MO-MM. FRENCH OUN (CON-
STRUCTED BY AMERICANS).

INTERIOR OF CONCRETE EMPLACEMENT FOR 340-UU. FRENCB OUN (CON-
STRUCTED BY AMERICANS).

610

TRACK WORK FOR HEAVY ARTILLERY.

503. The material which follows oa **The study and locating of
track/* ^* Track construction,'' ^'Placing of firing track," etc., has
been extracted almost verbatim from a translation of a French
pamphlet entitled '* Manual of the Course for Student Officers, "('•).
This manual was prepared by the French Service for the instruction
of officers assigned to their Railway Artillery Camp at Mailly, France.
The translation was made by Capts. C. L. Nelson and A. N. Clark,
Engineers, U. S. R., and was edited by Maj. Orville Benson.

504. Study and Locating of Track. — ^The studies and the locat-
ing of railway tracks are made by topographic parties of certain
regiments of the Corps of Engineers, or of the Standard Track Con-
struction Batteries, who are part of the Railway Artillery Reserve.

505. The beginning and end of a line are always indicated approxi-
mately by the authority that orders the studies. After making a
study on the topographic map, the chief of the party makes a recon-
naissance on the ground, covering the zone of the eventual construc-
tion. This reconnaissance will reveal to him the points of necessary
passage, the points favorable for the departure A, and of arrival B,
the obstacles to be avoided, the parts defiladed from the view of the
enemy, the camouflage which will be necessary, and permits the
determination of the strip of land on which the location is possible.

506. In default of a good topographic map, it is necessary to run
a grade line on the ground, to make sure that the maximum grade
is not exceeded. The topographic, party then proceeds to survey
the aforesaid strip of land. An experienced operator runs a pre-
liminary traverse line there, formed by a series of straight aUgn-
ments, of which the extremities are indicated on the ground by
stakes. These stakes and alignments are chained {Aa, ah, he, cB)
and angles A, a,b, c, figure 1, plate 457, are measured with a transit,
beginning with A of the traverse. These measures allow the making
of a map of the traverse which is plotted on a scale of 1/2,000 or 1 /5,000.
On this traverse numbered stakes are also placed at all points (1, 2)
where there is a break in the slope. A level line is then run over all
the points, ^, 1, 2, a, 6, c, B, At all these stakes a cross profile is
surveyed reaching 30 to 40 meters to each side, in the same manner
that the longitudinal profile was made.

507. All of the lines of the traverse and the traverse profiles (cross
sections) are drawn on a plate. In this way one has the position
and elevation of all of the essential points of the strip of terrain; it
is easy to draw the contours on the plate. Another more rapid
method is to take stadia shots directly to the essential points of the
terrain from instrument stations placed successively at stations A,
a, 6, etc., of the traverse. On this contour map it becomes possible

611

Plate 457

/J^>V

lOMSmJUmL PKOHLE

r/s.a

I

^^J-

OfOSS SBC770N/N CUT

^

:^

/ cmss secncN /n fill

r 1

/76.S
CU& Ctmrj^TS OF B/IUjIST: 13 CUM PER RUfi M£7FR

—soo —

\ /A/COT

\11RA1BL£

df^mL

BS^ft^?=9!S5

^;^-

5/DfN6S

* <

Oa CQt^ENTS or MLUST: a7SC(/,M. KR /^UN. Af£7ER

\ /A/a/r

SLOPE

67A

2.SS

t^liit

a<Pi3HM?<4J*Jr44t*':.'-f!?

^.fl?

6^

^

>2&7

/TS-^

612

to study a line answering all the technical conditions imposed, which
will be discussed in detail later. This line, drawn in a heavy or red
line on the map, permits the plotting of the longitudinal profile, in
which the distances between different points of the terrain appear as
abscissae and their elevation as ordinates, figure 2, plate 457. On this
longitudinal profile one may draw the red line or profile of the track
by a series of grades joining the track of departure with the objec-
tive without ever exceeding the maximum grade.

508. When the red line passes underneath the black line repre-
senting the terrain the track is in cut; when the red line is above
the black line the track is on fill, figure 3, plate 457. The difference
in elevation between each point of these two lines of the profile
gives the height of the road bed above or its depth below the natural
surface.

509. In taking account of the vddth of the road bed and its em-
placement one may, in utilizing only the longitudinal profile, com-
pute the voluine of cut and fill necessary, and accordingly determine
the number of days' work. When the project is approved the line
is located on the ground; that is, it is staked out.

510. Staking. — ^The numbered stakes of the preliminary survey
are useful in laying out on the ground the line adopted, the distances
from the line to these stakes being scaled from the map.

511. Center Stakes. — ^The stakes are placed at the points of
tangency of the curve with the tangents. In the French Railway
ArtUleiy Engineers' Service, these stakes are painted white and
carry the letter **T" with a number in order; intermediate red
stakes, of which the numbers are of the same series as the preceding
ones, are placed every 50 meters, on tangents, and every 25 meters
on curves. A tack is driven in the stake at the center of the track.

512. Elevation Stakes. — ^These stakes are set in such a manner
that the head has the elevation of the top of rail. They are placed
at the side of the track, about 2^ meters from the rail. Breaks in
grade are painted in yellow and marked ** C, P.,'* with a serial num-
ber on stakes. Intermediate stakes of the same color every 50
meters are numbered in a series distinct from that of the line stakes.

513. Specifications of Standard Track. — Minimum radius of
curves, 150 meters; tangents to be inserted between reverse curves,
25 meters; maximum grade on tangents and on curves above 150
meters radius, 20 millimeters per meter, or 2 per cent. Reverse
grades should be joined by a vertical curve of 1,000 meters radius.
Gauge, distance between the inside of the heads of the rails. The
gauge used for artillery is slightly wider than for standard track
work, e. g., tangents and curves over 150 meters radius (4 feet, 8,875
inches), 1.445 meters; curves of less than 150 meters radius (4 feet,
9.312 inches), 1.445 meters. Spacing, C to C, of ties, 0.80 meters;

613

width of subgrade, 4 to 5 meters. The clearance required for rolling
stock is given by sketch, figure 5, plate 457. The rails ought to be
at least 1 meter from any obstacle, and it is necessary to increase
this distance on curves to allow for leaning and the cutting in of long
cars. A detailed discussion of clearances for American railways as
weD as French is given in paragraphs 664 to 688.

514. Earthwork. — ^The study of projects ought to be conducted
in such a manner as to make necessary the least possible amoimt of
earthwork. The execution of earthwork may be done, either by
the method of "borrow and deposit," in which necessary earth is
taken from borrow pits along the side and .excess material is thrown
back over the sides of the cuts; or by the method of "transports,"
in which the earth is carried from the cuts to make up the fills. While
the earthwork is in progress care is necessary that the grade stakes
be not disturbed.

515. The depth to which it is necessary to go to reach the subgrade
may be indicated to the excavators in a striking manner as follows:
(a) In cut, a hole, half a meter square, is made at the side of each
stake with the bottom at the level at the subgrade; or, the depth to
which it is necessary to descend is written on the head of the stake.
(h) In fill, the red line of the fills is represented in profile with pickets
of the proper length. In fills the height is increased 10 per cent to
allow for settling. The earthwork is controlled with a set of " nivellets
en bois."

516. Side Slopes of Cut and Fill. — ^In ordinary soil the slope
of a cut varies between 1 to 2 in height to 1 on the base. In chalk
one may adopt 5 in height to 1 on the base. The slope of fill is 2 in
height to 3 on the base; sometimes this is reduced to 1 to 1 to reduce
the base, figure 1, plate 478.

517. Amount of Earthwork per Excavator per Day. — ^A

man ought to dig and load into a wheelbarrow, or dig and throw with

one toss of the shovel, from 2 to 4 cubic meters of earth in cut in a

10-hour day. In firm soil, e. g., chalk, or moist soil, i. e., clay, the

production may fall to from 1 to 3 cubic meters. With a shovel a

man can load or unload from 8 to 10 cubic meters of soil, gravel, or

ballast per day.

TRACK construction.

518. Material. — In France two types of track have been adopted;
they are distinguished by the form of the rail and the method of
attachment to the ties. These are: (1) Voie Vignole or T rail; the
tie is notched to provide a seat in which the flange of the rail rests;
the rail is fastened to the tie by two or three screw spikes, figure 2,
plate 478. (2) Voie & Coussinets (chair track) ; the raU has a nearly
symmetrical section and is held by a wedge in the chair, which is
fastened to the tie by screw spikes, figure 3, plate 458. The rails

614

Plate 458

FIG. 2

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PROFILES, RAIL SECTIONS, AND SWITCHES.

615

should be ijiclmed 1 m 20 toward the axis pf the track so that the
bearmg surface of the head of the rail wid the wheel tread may be
parallel; in the first type it is the seating in the tie that gives the
inclination, and in the second it is the shape of the chair.

519. Superelevation. — To facilitate traveling on curves of short
radius 'an inclination is given to the track by raising the outer rail.
For railway artillery rolling stock, which travels at a slow speed, a
difference of elevation of from 3 to 5 centimeters between the two
rails is sufficient for curves of a radius of from 150 to 125 meters.
To bring the two rails on tangents to the same level the difference is
eased off along a length of about 1 2 meters beginning at the point of
tangency.

520. Expansion and Joints. — A small space is left between the
rails when they are laid to allow for the expansion of the metal.
This interval, which is a function of the length of the rail, should be
veiy large in summer and very small in winter. In France a varia-
tion of 0.6 millimeters per meter is allowed between the two extremes
in temperature.

521. Plan op Placing or Laying Ties. — The spacing between
ties may vary between 0.5 and 0.85 meters. In general the following
numbers for rails of different lengths are adopted :

Length of rail. Ties per rail.

5.50 to 6 meters 7

8 meters ., 10

11 meters 14

12 meters 16

522. Plan of Placing the Rails. — In standard gauge mihtary
track laying the rail joints should be exactly opposite each other.
Since the lengths of the radii of the inner and outer rails on curves
differ to the extent of the gauge of the track, it is necessary to
supply rails of different lengths to obtain this result. For quick
laying in a campaign the rails are usually supplied in equal lengths,
and the following principles are then adopted :

(1) Trails: Little attention is paid to the locating of the joints.
They may fall on a tie, since this does not prevent the rails from
being spliced and screwed to the ties ; or, the joints may come between
the ties. In this latter case the ties at the joint should be a little
closer together to lessen the suspension of the rails.

(2) Chair rails: With rails of this, type it is Necessary, of course,
that the joints come between the ties, and the requirements, espe-
cially on curves, will be a little more severe.

523. In laying rails of either type the following principles are fol-
lowed with reference to the relative position of opposite rails: (a)
On long tangents the joints should be even, (b) On curves the
joints should be staggered with an overlap of about half a rail length*

616

(This necessitates starting with half a rail length at the point of
tangency.) (c) On crooked lines or wherever tangents are not
predominant, staggered joints should be used throughout the entire
length.

TRACK LAYING.

524. Before beginning the track laying it is necessary to check for
the stakes that may have been disturbed during the excavating.
These stakes will serve as guides for distributing the ties and the rails,
and after the ballasting has been completed they will serve as guides
for the exact placing of the track. Following are brief rules for the
laying and assembling of the track components:

(a) Ties: The ties are properly spaced by means of a gauge and
are aligned approximately through the use of the rail notches as
guides.

(b) Rails: As noted in the preceding paragraphs, spaces should be
left at the joints for expansion, and care should be exercised to avoid
any considerable displacing of the ties.

(c) Joining of the rails: . The connecting or fish plates are placed
at the rail joints and bolted tight.

(d) Adjustment of ties: After the rails are bolted together the
exact positions of the ties may be marked off on them with chalk,
and the ties adjusted to this marking by hand or with bars.

(e) Spiking or wedging: As soon as the ties are adjusted the
rails may be spiked to them, using a gauge to keep the rails the
proper distance from each other, if T rails are being used. If
rail chairs are provided, these chairs will have been previously spiked
to the ties at 'proper distances apart and the rails need only be wedged
into them.

(f) Firing track: For this section of a track T rails of a heavy
weight and from 11 to 12 meters in length are always used. No
particular attention need be paid to the locating of the joints. Par-
ticular attention must be paid, however, to the locating of the ties
with respect to the holes in the structural steel sliding beams.

525. TuKNOUTS. — ^A turnout is composed of three parts. These
are (1) A switch, which is the operating section; (2) a junction,

. which carries two ordinary tracks; and (3) a crossing with a frog or
guard rails. A crossing may be defined in two ways — that is, either
by the angle between the two. tracks which it cuts, for example, 5
degrees and 30 minutes, 7 degrees and 30 minutes, which are angles
in use on the Est Railway, or by the tangent of the angle between
the two axes.

526. Study of Turnouts. — ^In preparing for the placing of a switch,
the type having been determined, it is necessary to know the follow-

617

ing: (1) The total length of the turnout, L, and (2) the position of
the tangent of the turnout, TTj which is defined by the position of
the point -B, with intersection of the axes/ with reference to one end
of the switch, and by the angle between the two axes, figure 5, plate
478. Figure 6, plate 458, illustrates the standard 5-degree 30-minute,
model 1909, 45-kilogram rail switches in use on the Est Railway.

527. Ballasting and Adjusting. — Before ballasting, grade stakes
are set regularly at intervals of 25 meters as well as along or inside
the track at changes in grade. The top of a stake gives the elevation
of the rail (inside rail on curves). The quantities of ballast per
meter of track are: (1) Through tracks, 0.60 cubic meters to 0.75
cubic meters, according to the nature of the terrain; (2) firing tracks,
1.200 cubic meters.

528. The straightening, adjusting and tamping is handled succes-
sively, and with repeated corrections until the desired regularity both
in plan and profile is obtained. The raising of the track includes:
(1) The raising and bringing to grade of points at the grade stakes,
and (2) the raising and bringing to grade of all points between the
grade stakes. In this second raising three little blocks of equal
heights may be placed at the points first raised and the point being
raised for convenience in sighting. The track having been raised
by means of screw jacks or levers, the ballast is gradually filled in and
tamped ufider the ties with tamping picks or bars. The tamptngr
should be energetic under the rails and to a distance of from 30 to 35
centimeters on either side; under the middle of the tie it should be
very gentle. The straightening is handled ordinarily by a gang of
about a dozen men using large bars. The track is lined up with the
line stakes by measurement and for final and fine adjustment by
sighting with the eye.

529. EoLMER Switch. — ^The instaUation of the standard type of
switch generally requires two days with a gang of 20 trained men and
necessitates the complete cutting of the main line for a distance of
about 30 meters for several hours. The Eolmer is a removable
switch which can be placed in a few hours at any point whatsoever of
a track in service and without taking up the raib. To clear the main
line £or traffic, it is necessary to take up only three pieces of the switch,
which can be done in about 10 minutes.

530. The whole of the Eolmer switch is represented in figure 1,
plate 459. It is shown here turned to the left. The switch points,
6 and Z?, fit to the main line rails on the top instead of along the side.
The tops of the switch points are shaped to a gentle grade and raise
the wheels gradually imtil the flanges are aboVe the rails of the main
track. At this point the wheels may follow the switch and they
defijiitely leave the main line when the one wheel crosses the frog at
Cf figure 3, plate 459. Figure 2 shows how the points are attached

619

and figure 3 shows the type of frog used. It is necessary to take up
only three pieces of the switch, the two points and the frog, to reestab-
lish the main line. The pieces of rail MM may be left in place.
Naturally the turning off of a locomotive and railway gun carriage
to an epi by means of a removable switch requires care and very slow
speed. It has been used, however, with perfect success and the sav-
ing in time in installation is so great as to commend its use.

531. Grade Crossings. — Crossings for the passage of wheeled
vehicles arc shown in section in figure 1, plate 460. On both sides of
the track, slopes of well rammed earth covered with gravel or rock are
made. Inside the track the space is brought to the level of the rails
by well rammed gravel and earth flanked by ties or timbers placed
0.05 meters from the rails, and spiked to the ties. It is of course
preferable' to build up the entire space between the rails at grade
crossings with timbers if they are available.

532. Buffer Stops. — ^At all dead ends of tracks some variety of
buffer stops should be constructed. If material and time are avail-
able, an effective stop can be constructed of ties reinforced by a
momid of earth as shown in figure 2, plate 460. If less time is avail-
able a stop may be constructed of several ties laid on the track and
reenforced by a mound of earth, figure 3. A single tie backed up by
two rail clamps of the variety used with the 19 and 24 centimeter
French railway mounts is effective.

533. Reversing Triangles (Wyes). — In artillery parks or yards
or in a position on the front in the vicinity of which a number of
firing positions have been installed, i. e., any place where it is not
practicable to provide turntables of the usual type for reversing loco-
motives, railway mouints, etc., reversing triangles or wyes must be
provided. In yards this may be especially laid out for the purpose or
on the front it may be made by connecting an existing spur with the
main line by* an additional curve forming a triangular inclosure or

wye.

EPIS.

534. Railway mounts are operated on a specially constructed piece
of track called a ''firing track'' (epi de tir). These tracks (epis) are
constructed for two classes of gun mounts: (1) Those which are
supported by firing beams (Poutrelles) at the moment of firing, so
that the shock of recoil is absorbed by sliding friction along the beams;
(2) those in which the shock of recoil is absorbed by hydraulic
cylinders, the mount being securely clamped to the track which, in
the case of the heavier gims, is reenforced to withstand the shock of
firing. Epis are curved in such a way that guns can be oriented, to
cover the desired field of fire, by moving them along the track. The
''Orienteur officer" places grade marks on the web of the outer rail
of the curve as a guide for the battery commander in placing the gun.

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CROSSINGS, TRACK ENDS, AND FlRTNfl TRACKa

621

SUDING MOUNTS (MATSRIELS a GUSEMENT).

535. Guns mounted on sliding carriages are fired from a track
called a firing track or epi, laid on the arc of a circle so as to permit
the orientation of the piece to cover the field of fire selected. For
firing, beams (poutrelles) are placed parallel to the rails and screwed
to the ties; the jacks which relieve the wheel trucks of their load bear
on these beams and provide friction for absorbing the shock of recoil.

536. Firing Beams. — ^The above platforms- or beams are about
37.50 meters long. This length permits 8 grads (7.2 degrees) field of
fire for a curve of 200 meters radius and 10 grads (9 degrees) for a
90-meters curve. They should not be fastened to the ties before the
gun is ready to occupy the position to fire. They are then fastened
with screws in the holes that will be mentioned in the next para-
graph.

537. Firing Epi Construction. — ^The firing epi for each piece is
a curve constructed with special T rails (45 kilograms) and chamfered
ties (0.15 by 0.30 by 3 meters). Firing tracks have no super-eleva-
tion. The gauge is from 1.45 meters (4 feet 9.062 inches) for a curve
of _150 meters radius to 1.455 meters (4 feet, 9.312 inches) for the
smallest radius (90 meters). The special ties are not shod, but are
delivered bored for track screws. They should be spaced 0.54
meters, C to C, on center line of track. Holes are provided in the
ties to receive the screws for both rails and beams. To prevent
ballast from getting into these holes it is well to plug them with
straw or hard grease. The ends of the tie in which the distance
between the holes for the rail and the beam is the greater must be
laid on the inside of the curve. After the ties are laid, their proper
position should be verified by running the eyes over these holes,
figure 4, plate 460. Track screws of a standard type and size only
should be used in these ties; nothing else that might change them
or prevent their being used again should be used. At rail ends, the
screws must be carefully screwed down and not driven down with
a hammer.

538. Ballast. — The ties should be laid on a bed of excellent
ballast, 0.15 meters (6 inches) thick, extending 1.50 meters beyond
each end of the ties. The tie should be completely buried in the
ballast throughout its length. The resulting bed of ballast will be 4
meters wide at the top and 4.60 meters at the bottom; this will re-
quire about 1.50 cubic meters per meter of track. The ballasting
should be done with special care, the tamping being done preferably
with bars.

539. Epi Limits. — ^An epi is usually defined by its point of begin-
ning and the direction of its two ends, but to avoid confusion it

622

should always be made plain whether extreme directions refer to the
desired field of fire, or to the construction of the track itself. SuflB-
cient trackage must be provided for the auxiliary equipment, either
ahead or to the rear, depending on its relation to the working of the
gun; the length of the curve must exceed that corresponding to the
field of fire prescribed in order to provide for corrections in aiming,
usually an equivalent of 10 degrees are added to each end, making
a total increase of 20 degrees in the curve.

540. Epi Specifications. — In general the firing epi has a uniform
curvature; but in a very exceptional case the terrain may make it
necessary to adopt an irregular curve; in such case the radius must
never be less than 90 meters (approximately 300 feet), and the ex-
treme direction must be maintained in such a manner that the tan-
gents to the curve will sweep the entire field of fire progressively as
the gun advances along the epi. In general also, the epi should be
level, but to facilitate its adaptation to the terrain, a grade not exceed-
ing 5 millimeters per meter (5 per cent) may be used. In every case
the epi should be constructed in cut, so as to assure a solid platform
for firing; exception "may be made for those sections of the epi occu-
pied only by the end trucks in extreme fire since they would never
receive the shock of recoil. If fill is unavoidable, as for instance in
crossing a ditch or depressed road, the fill must be made with good
ballast well rammed, with no voids whatever that could cause settle-
ment. When the cutting becomes deep it is well to have its sides
made in steps to faciUtate the get-away of personnel at the moment
of firing.

541. Battery Epis. — In whatever way the epis of a battery are
arranged, sufficient space (at least 50 meters) must be allowed that
there shall be no danger that one shall suffer from the blast of the
other. When the two epis are near each other, they should be
concentric so as to insure a common direction of fire. Usually two
epis are constructed together with a common center, having res-
pective radii of 90 and 140 meters.

542. Group Epis.^With a group consisting of four pieces, the
'* group epi*' may consist of four epis together made up of two ** bat-
tery epis'' in some form, bearing in mind the ** blast" mentioned in
connection with '* battery epis." Parallelism of four pieces may be
secured by arranging the epis in a forceps form, figure 5, plate 460.
This form may be approximated by separating the curve centers,
figures 6, 7, and 8. Other forms necessitated by the terrain are,
the ''palm," consisting of four epis with a common center, figure 9,
or of four epis curving the same way, but having different centers,
figure 10. A gun must always be at least 50 meters from the field
of fire of neighboring pieces.

623

MOUNTS WITH HYDRAUUC RECOIL (MATfiRIELS a FREIN).

543. Among the gun carriages provided with hydraulic recoil,
some of the lighter ones (6 to 10 inches), may fire from any track on
the condition that the track be reenforced whenever it is used for
firing. The material is not dismounted. The stability of the car-
riage is secured generally by the use of clamps which fasten the car-
riage to the rails and by hinged outriggers provided with jack-
screws supported by footings placed on the ground. The stability is
increased by adding several well-tamped ties under the rails, and by
placing, under the ends of the ties, on the side of the recoil, longi-
tudinal ties held in place by several stakes sunk deeply into the groimd.
If the ground is too yielding, long stakes may be sunk into the ground
between the ties, on the heads of which supplementary ties are placed.
In addition longitudinal ties are laid against the ends of the ties and
are held in place by stakes, figure 11, plate 460. A thorough tamp-
ing under the ties concerned is indispensable.

544. The carriages for the larger guns (12 to 16 inches) require
the construction, under the firing track, of. very strong platforms
sunk into the ground, of which the details differ according to the
caliber and the design of the mount. The installations require from
one-half to four days, likevrise according to the caliber and design.

CAMOUFLAGE OF RAILWAYS. (37)

545. The camouflage of railways, especially firing positions, to
conceal them from the view of airplanes and above all to keep them
from appearing on photographs is very difficult. The Germans,
who were very attentive to this question were, in general, not able
to conceal their tracks and firing positions except in the woods.

546. At the beginning of the appearance^f the railway artillery
at the front, little attention was paid to the camouflaging of the tracks.
The mobility of tliis artillery, the great distance between the pieces
and its distance from the lines (nearly always more than 5 kilo-
meters) haVe been its best protection. It has remained almost
imharmed, while according to the maps found on prisoners, it is
established that the curved epis of the Somme were nearly all known
to the enemy, and most of the firing took place in view of the ' * drach-
ens'* (observation balloons). It is nevertheless of interest to con-
ceal preparations for attack from the enetny and to hide from him
the cannon in action to avoid counter-battery fire.

547. Access Tracks. — It has been recognized as advantageous to
conceal the switch and the first 200 meters of the tiu*nout to a firing
position under tents of cloth and fireproof raffia. It is desirable to
place the tracks in a woods, disturbing the trees as little as possible,
and bringing the branches together over the track. Tracks may be

181768—21 40

624

laid along the edge of woods to conceal at least partially the new
earthwork, or on beaten roads, thereby avoiding earthwork which
easily attracts attention. The rails and ties may be masked under
ballast or cloth and deceptive road ends may be made at a notice-
able point such as quarry, a wood, a farm, or another road by a false
branch made up entirely of painted cloth. The true entrance should
be concealed under cover of the woods, making a turnout and a false
entrance further along.

648. Firing Epis. — Experience has shown that one need not
consider the masking in a group of curved epis of any but the direct-
ing gun (^'Directrice'Oj by concealing the switches and completing
the curves by false track. Complete camouflage of the whole work
would be long and of little use. It will be well to make false epis
in the neighborhood by means of a simple turning over of the earth
with a plow, by simulating pieces covered with tarpaulin, and by
placing on the true epis false shell holes to make it appear that the
access to or the use of them is impossible.

549. Single epis, curved or straight, are much easier to camou-
flage. First, one can often place them in woods or ravines; when
they are very short, as in the case of the howitzers, it is even possible
to cover them completely with cloth or rafiia. It is desirable to
avoid the use of geometrical curves in the access tracks. In open
country these epis can be prolonged by a false road or a false track
to a natural point of attraction, as another track or road, or to a
quarry or a town; if one doesn^t succeed in concealing the railroad,
one has at least a chance for hiding the epi itself, and that is what is

most important.

GARAGES.

550. Components. — ^Blach garage for heavy railway artillery
comprises chiefly, a line track, a passing track paralleling the line
track throughout the length of the garage, and which serves as a
maneuvering track, some storage tracks reserved either for firing
trains or for personnel trains, and branches on the maneuvering
track, plate 461. At some place in the complete system there must
be a Y track for turning. In certain garages, the tracks for person-
nel trains are not ballasted. This economical plan presents no diffi-
culties provided the personnel trains only are admitted to them. As
far as possible, no tracks for firing trains should have dead ends, in
order that they may not be blocked in. Garages are established at
suitable points where the ground is level, near a road to facilitate
supply renewals and where water may be had. Usually two or four
groups can be imited.

551. Length of Tracks. — ^The lengths adopted for the storage
tracks vary according to the equipment. For a group of four 32-
centimeter guns there is generally allowed 350 meters for the firing

625

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626

trains and 350 meters for the personnel trains. The radius of 150
meters has been adopted' as the most suitable for curves on garage
tracks; for sharper curves over which guns are to be moved super-
elevation must be given.

552. Water. — ^If the water supply points be near, the locomo-
tives go there, separately according to a rotation regulated by the
commanding officer of the camp. If there is a place to fill water
cars, or if the soxu-ce of water supply is distant, provision is made
for one or several water trains, which circulate as conditions require,
to supply all groups which occupy the garage. In case the source
is distant, locomotives supply themselves at the water cars of the
group.

553. Fuel Depots. — It will be convenient to arrange, at a suitable
storage point, a small depot, independent of the fuel supply which
the groups maintain in the supply cars, where all the groups may
replenish their supply.

554. MiscELijkNEOUS Installations. — ^It is advisable to build
a ballasted road to accommodate automobile trucks, for supply
replenishment, between the nearest main road and the garage. In
each garage, there should be built a hut or switchman's shanty for
the yardmaster and a hut to serve as a telephone central for con-
necting the units stationed at the garage. The telephone lines will
connect the yardmaster with the '*chef de la gare'' of the junction
of the railway artillery line with the main line and with the post of
the switchman stationed at the exits of the garage. It is necessary,
moreover, to provide for each garage such operating equipment as
red and green flags, green, red and white lanterns, lights for the yard-
master's hut, and materials for maintenance of switches. The main-
tenance of the garage trackage is the duty of the permanent personnel
of the garage, aided if necessary by auxiliaries furnished by the various
groups. A small supply depot should be established for this purpose.

MAINTENANCE OF TRACKS.

555. Requirements op Gtood Tracks. — ^A good track must be
regular in alignment and profile without kinks or sharp bends. The
inspector satisfies himself on these points by going over the line and
verifying the regularity of alignment, straight or curved. To verify the
profile by a glance of the eye, place the eye from time to time close
to the rails, looking along the track as far as possible. The ends of
the rails must not touch each other, a space between them suflBcient
for expansion being required. Each joint must be formed with two
splice-plates fastened with four bolts (for heavy work six bolts are
used). Flange rails must be fastened to each tie with at least two
screws; double-headed rails must all be wedged into the bearings
by the wedges of wood or iron. Every bent or broken rail makes

627

traffic dangerous, and must be replaced. Loose ties (insufficiently
tamped) must be made solid by tamping; broken or rotted ties
which depress under the passing of trains must be replaced at once,
as they cause derailments. The spacing of the ties must not exceed
80 centimeters, C to C, to avoid bending of the rails. The ballast
must be porous and firm; if the base is wet or muddy it lacks resist-
ance, and must be drained or the track will not retain its profile.

556. Dressing and Raising the Track. — ^Defects in the align-
ment are rectified by a gang of 6 or 10 men, equipped with pinch-
bars or levers and directed by a gang foreman. The pinch-bars are
set under each rail and the men heave together, at the command
"Oh Heave!" At points which are too low it is necessary to raise
the track by means of lai^e wooden levers called handspikes or
with small jacks. The jacks are set under the ties, and never under
the rails. The ballast should be adjusted imder the lifted ties.
For correcting the track grade, three wooden leveling blocks of the
same height should be used; two are set on the rails at points of
correct grade and the third on the rail to be raised. The point be-
tween is at grade when the tops of the three blocks are in the same
plane. The heights of the three leveling blocks should always be
checked before using them.

557. Replacing and Tamping Ties. — ^To replace a tie it is neces-
sary to remove some ballast, remove the screws from the tie, lift out
the wedges and the cradles and withdraw the tie by means of picks.
The new tie is then slipped imder the rail and tamped temporarily;
after placing the screws, or the cradle and wedges, if used, the tamp-
ing is completed. Four workmen are sufficient. In tamping, two
men work together at the same end of a tie, piling a little ballast
against each side, and forcing it under by blows of a mattock or a
tamping bar.

558. Replacing the Rails. — The splice plates and a row of screws
or spikes are removed along the rail if fiange rails are used; the ex-
treme splices and all the wedges are removed if double-headed rails
are used. A cut of rail of equal section and length may then be set
in the opening, the men being placed about a meter apart along it.
Its flange will be engaged under the heads of the screws or spikes in
place, or in the opening of the cradle, some space being allowed at
the two ends of the rail. The splices and the screws, spikes, or
wedges will then be replaced and the job finished by dressing or tamp-
ing. All screws and bolts should be greased before screwing them in.

559. Repairing a Cut Made by a Shell. — A shell of large caliber
falling on a track ordinarily breaks 8 or 10 ties, and twists the rails
for a distance of from 20 to 30 meters. It is necessary first to pro-
vide the ties, rails, splices, bolts, wedges, and screws estimated to
be required for the repair. Laborers should be sot to filling the hole.

628

«

ramming the soil in layers at the same time that the trackmen are
removing the twisted rails and the ties on which they rest. As soon
as the. shell hole is filled the ballast can be restored and the ties and
rails replaced, spliced, and, spiked or wedged. The work will be
finished by dressing the track for alignment and profile, and com-
plete tamping.

560. Track Drainage. — New drainage ditches should be made
deep and old ditches kept clean. They should always be provided
in cuts and on level ground to assure a flow of the water. If neces-
sary, drains of tile, stones, or of bundles of boughs should be installed
beneath the track and joining the two ditches.

561. Handling of Track Material. — ^Two men can carry an
ordinary tie (weight 80 kilograms). It requires three men to carry
a tie with cradles attached (weight 125 kilograms). Four men are
needed for firing track ties (3 meters long, 160 kilograms). Rails
ordinarily weigh, double headed, 38 kilograms per meter, and flanged,
45 kilograms per meter. For the carrying of rails, an allowance of
one man for each meter of length is made. Small supply depots
of rails, ties, splices, etc., for possible repair work, are generally
established at intervals of about 1 kilometer along military railroads.
It is necessary that all officers of railway artillery be able to direct
a small job of construction or repair work.

DEPLOYMENT OF RAILWAY ARTILLERY ON THE ATTACKING FRONT.

562. Railway artillery, being difficult to conceal, is ordinarily
employed in the mass. In the region of attack, there are united as
many positions as possible with a view to meeting various tactical
situations; positions in the rear for demolition fire, advanced posi-
tions to be occupied on the days of attack, and contingent positions
for pursuit, whence to support the infantry as long as possible.

563. There is constructed, parallel to the front, a supply line (voie
de recade), plate 461, connected with two operating lines. This
track is generally constructed by the S. C. F, (service de Chemip de
Fer — equivalent to our railway engineers). From this line, which
the Army uses for rationing and the transportation of munitions,
there extend various branches which lead to position 1, 2, 3, etc.
Near the supply line there are distributed the garages for firing
trains and personnel trains, the water-supply points, etc. A single
supply line may extend over 40 to 50 kilometers length along the
front.

Note. — ^The French use the expression "voie de recade," here translated "supply
line/' to apply to the track system approximately paralleling the entire western
front from Dunkirk to Belfort, and style the train that traverses it daily "The Recade."

564. The access tracks that lead to the position are sometimes
4 or 5 kilometers long; with an average of 2 kilometers to a position,

629

the four curved epis of a group represent a total length of from 600 *
to 800 meters. The equipment of an attacking front generally
calls for the laying of 200 kilometers of track, taking into considera-
tion the retention of existing trackage. The amount of earthwork
involved in the construction of the access tracks and firing tracks
of a group sometimes reached 8,000 to 10,000 cubic meters per
position, the average being 2,000 to 3,000 cubic meters per position.
The extent of trackage for railway artillery garages and ammunition
dumps on the front of any army is from 15 to 20 kilometers.

565. A military laborer, who costs 5 francs per day, excavates 2
cubic meters per day and lays 4 meters of track on au average.
Ordinary ties cost 15 francs each, firing track ties 25 francs, and rails
60 francs per 100 kilograms. This gives an idea of the expense of
railway artillery trackage. It is necessary that the entire personnel
of the railway artillery be entirely familiar with their duties, to make
the best use possible of the powerful and expensive equipment that
is entrusted to them.

SUPPLEMENT TO TRACK LAYING.

566. To Stake Out a Straight Line Between two Fixed
Points. — ^The chief of the party places himself 20 meters behind
one of the points and sends the rodman 50 meters ahead. The
rodman places and drives a stake so that its foot is in line with both
fixed points. (lining it in by eye.) He continues to place stakes
at desired intervals which the chief of the party lines in from his
original position as long as he can effectively do so. If the line
goes through a depression, the chief may go forward and line up
stakes with those already set.

567. To Find the Intebsection of Two Alignments. — ^A rod or
stake X, figure 1, plate 462, may be set at the intersection of align-
ments AB and CD, by placing observers at A and C or at stakes on
AB and CD, respectively, who line in the rodman's pole or stake
alternately until it coincides with both lines. If the rodman is
using a stake, he carefully drops it and drives it in where its point ^
strikes.

568. If the operator is alone, he stations himself at the approxi-
mate intersection and marks the spot with a stake, figure 2. He
then places a second stake on AB about 10 meters from the inter-
section, lining it up with the first stake and A or B,Q3 the case may be.
Next a third stake is placed on AB and about 10 meters on the other
side of the first stake. He then disregards the intersection stake
and begins to line up the stakes a and b with A and B, Fjom a he
lines in b with B, moving b (not o) imtil it is in line. Then he
sights from b and lin^ in a with A, moving a (not b) until it is in
line. It may be necessary to go from a to 6 a number of times in

630

631

this procedure until the stakes are perfectly in line. Stakes c and d
may then be lined in with 0 and D in a similar manner. The locating
of X as the intersection of ah and cd needs no explanation.

569. To Erect a Perpendicular at a Point M of an Align-
ment Determined by Two Stakes, A and B, Without Instru-
ments.— ^This solution is based on the fact that if the legs of a right
triangle are 3 and 4 or any multiple of 3 and 4 units in length the
hypotenuse is 5 or a similar multiple of 5 units in length. From
3f toward B a distance of 4 units (meters, yards, or any length marke"d
on a stick) is measured and staked at C, Then a length of 3 units
is measured on one string or stick and 5 on another. The 3-unit
string is attached to M and the 5-unit string to C. If their ends
are brought together, keeping them uniformly tight, a point D is
located on the desired perpendicular. MD is the perpendicular.

570. To Measure Distance Along the Grade. — ^The chain is
stretched on the ground. The rear chainman keeps his ;5ero mark
on the head of the starting stake, or against the pin already set.
The head chainman stretches the chain and sticks the pin at the
end mark. He stands on the side of the chain, the shoulders in
line with the rear chainman, and head turned his way; he moves
backward or forward according to the directions of the rear chain-
man. The arm extended indicates to which side he ought to go;
the arm suddenly lowered indicates that he is to stake the pin.

571. After sticking the pin the chainman ahead moves on, keeping
the chain stretched. When the rear chainman finds the pin pre-
viously set, he holds his zero mark and directs the head chainman,
waving him on when the pin is stuck. When the head chainman is
out ot pins, he will still continue to stretch the chain its full length
from the last pin set, then leaving his handle on the ground, he
comes back to the rear chainman, from whose hands "he receives
anew the 10 pins, which he is careful to count while returning to
his place. This is what is called the exchange of pins, which takes
place every hundred meters. The chief of party takes note each
time so as not to forget the number of "hundreds.

572. To Measure by Horizontal Steps. — ^If the ground slopes
down the head chainman takes a loaded pin in his right hand, raises
the handle to get the chain horizontal and pulling on it hard, lets the
pin drop. He replaces it afterwards by an ordinary pin.

573. Laying Out a Curve. — The tangents CA and DB, figure 5,
plate 462, are given and they are to be joined by a curve the length
of whose radius, 7?, is assumed, hence is known. ': f instruments are
available, it is best, 'of course, to set a transit at A and having com-
puted the subtended angle for a standard chain length, lay off from
A successively the points on the curve to B. If a transit or compass
is not available the curve may be staked approximately by the
method of ordinates and abscissa as follows: For any abscissa

632

AP, which may be called X, the ordinate PM or y is found approxi-
mately by the formula y = X/2/?. Thus, for example, if iJ = 150
meters, a table of ordinates and abscissa can be quickly computed.

X Y

20m. 20/300 = 1/15= .66 m.
40m. 40/300 = 2/15 = 1.32 m.
60m. 60/300 = 3/15 = 1.98 m.

The distances X are then measured from A along AS and the
corresponding distance Y perpendicular to AS, thereby locating
points on -the curve. It will be best not to attempt to locate more
than half the curve from AS. The same values may be used in
locating the other half of the curve from BS.

Table of coordinates on the tangent for laying offciincs.
(Equal distances every 10 meters on the arc.)

Kadlos of the curve (meters).

go

9.979
19.830
29.447
38. 090
47.407
55.052
03.153
09.873
75.732
80.057

S

O

0.555

Z213

4.954

8.744

13.535

19.270

25.877

33.275

41.373

50.070

100

110

120

125

190

a
SB a

M 9

5«

9.963
19.807
29.552
3&942
47. 943
50.404
04.422
71.730
78.333
84.147

o

0.500

1.993

4.400

7.894

12.242

17. 407

23.510

30.329

37.839

47.970

a

o«i

ss

^1

s

a

a

« 9

5«

1

9.960
19.890
29.029
39.124
48.290
57.000
05.470
73.132
80.289
80.784

0.454

1.813

4.060

7.193

11.109

15. 962

21.531

27.831

34.810

42.409

CO O

9.988
19.907
29.688
39.263
48.566
57.531
66.097
74.204
81.797
88.821

d

o«i

s

^*

an 3

d

*** CB

a

•2

c

0.416

-5

9.969

1.663

19. 915

3.730

29.713

; 6.605

39.321

1 10.287

48.677

14.685

57.722

19. 844

66.398

25.693

74.650

32.197

82.423

39.311

89.670

5

a

o*i

ss

II

1

« a>

5«

S

0.400

9.990

1.597

19.921

3.583

29.734

6.346

39.371

9.867

4&776

14.126

57.892

19.093

66.668

24.738

75.045

31.024

82.081

37. 911

90.425

0.3S4

1.535

3.440

0.105

9.497

13.002

18.397

23.848

39.929

36.002

H

So
p. a

M.

10
20
SO
40
50
60
70
80
90
100

Radius of the curve (meters).

140

150

a

a

o*i

o«i

CO g

•

s

eo S

i

MO

fl

MO

■3

5«

0.357

5«

5

9.991

9.993

0.333

19.932

1.426

19.941

1.331

29.770

3.202

29.801

2.990

39. 457

5.674

39.528

5.302

4&943

8.834

49.079

&257

58.180

13.661

58.413

11.841

67. 118

17.138

67.487

16.039

75.716

23.241

76.261

20.833

83.927

27.945

84.696

26.200

91.710

34.221

92.756

32.117

160

P
• St

B

o

175

OS S,
M M
M S

9.993
19.948
29.825
39.585
49.190
58.604
67.788
76.868
85.328
94.010

0.312

9. 994

1.248

19.956

2.804

29.853

4.974

39.653

7.749

49.322

11. 119

58.831

15.070

68.148

19.587

77.242

24.052

80.085

30.246

94.044

s

1.1

o

0.285

1.142

2.565

4.552

7.094

10.185

13. 814

17.969

22.637

27.801

190

5|

M O

9.995
19.903
29.902
39.705
49.424
59.007
68.427
77.656
86.671
95.446

0.263

1.052

2.364

4.196

6.541

9.395

12.749

16.594

20.920

25.713

200

a

o

M

Si'
si

5«

9.996
19.967
29.888
39.734
49.482
59.104
68.570
77.884
86.993
95.885

£
I

•2

o

0.250

0.999

2.240

3.867

0.318

8.933

13.128

15.788

19L9U

24.484

SECTION 6.

PRBPARATION OF FIRING DATA AND SCHEME OF FKE

CONTROL FOR LAND WARFARE.

574. This discussion of the preparation of firing data and the scheme
of fire control must necessarily be brief, and hence incomplete. No
attempt will be made to give more than a general outline of the pro-
cedure. The theoretical points connected with the different methods
of laying the piece will be considered first. Next the procedure in
the case of a sliding mount firing from a curved epi will be described
in detail, and, finally, a discussion will be given of the various cor-
rections made to firing data and the methods of determining them.

575. Laying the Piece. — ^Laying the piece includes the opera-
tions of giving the gun the required elevation and direction. Lay-
ing in elevation is accomplished through the use of a vertical meas-
uring instrument, such as the range quadrant, elevation quadrant,
(pi. 464), or gunner^s quadrant (pi. 465). Laying in direction is
accomplished through the use of a goniometer (French) (pi. 466), or
a panoramic sight (American) (pis. 467 and 468), in connection with
an arming or reference point.

LAYING FOR DIRECTION.

576. Laying for direction, is accomplished through the use of a
few instruments of which there is a wide variety of designs, and on one
of two principles differing radically in their basic conception. Under
the one principle the laying diagram assumes the reference point at
a finite distance from the sighting instrument, and under the other
it is assimied at an infinite distance. In either case the sighting
instrument is set at a calculated or measured angle (usually calcu-
lated), which is one of the two supplementary angles between two
vertical planes, one of which passes through the axis of the gun and
the other through the line from the gim to the reference point, and
the gun is moved until the vertical cross line of the instrument is
laid on the reference point. Obviously, then, when the sighting
instnmient is laid on the reference point the gun is pointing in the
direction of the target. To determine the deflection angle, it is
necessary to know the gisement of the line from the theoretical posi-
tion of the gim to the finite or infinite reference point and to be able

(635)

STANDARD ELEVATION QUADRANT USED WITH ALL RAILWAY MOUNTS.

GONIOMETER (FRENCH) FOB TRAININa OUNS IN AZIUDTH.

OONIOHETER (7RENCH) FOR TRAINING GUNS IN

611

Pun 4666

(FRBNCH) FOR TRAINING OtlNS IN AZIMUTH.

STANDARD PANORAMIC SIGHT USED WITH ALL RAILWAY MOUNTS.

FANORAUIC SIGHT MOUNTED ON AUTOMATIC SLOPE COMPENSATING

644

to compute the gisement of the gun-target line. (The gisement of
a line is its angular direction, measured clockwise, with reference to
a north and south line through the zero point of the sjrstem of quad-
rillage. Azimuth is a somewhat analogous term, but is not exactly
the same, since it is the angular direction. of a line also measured
clockwise, but with reference to a north and south line through the
point at which the line is being considered. Since north and south
lines are not parallel, obviously the azimuth of a line running, e. g.,
north 45^ east, is not the same at points 5 miles or eyen 1 mile apart.)

577. Finite Aiming Point. — If the sighting apparatus is directed
on a visible and fixed reference point, either improvised or natural,
at a finite distance, this point is caUed a finite aiming point Under
such circumstances the goniometer, or panoramic sight, is always
attached to the gun and is set at the calculated angle. This scheme
of laying is most generally applied to field mounts and to railway
artillery having fixed emplacements.

578. Infinite Aiming Point. — ^If instead of a visible and fixed
reference point an aiming rule is used, we have what is called an
infinite aiming point. An aiming rule is a bar of iron L-shaped in
cross section about a meter and a half in length, which is mounted
on two heavy iron stakes set about a meter apart (pi. 469). Provi-
sion is made in the mechanism on the heads of the stakes for adjust-
ing the bar both vertically and horizontally. In the outside of one
leg of the bar there is a V groove in which two of the legs of the
small iron tripod holding the goniometer, or panoramic sight, slide.
When moimted on this rule a sight may be moved through a dis-
tance of nearly a meter and a half, all positions of the line of sight
being parallel to each other. The use of an aiming rule, of course,
always involves the use of either another sight or a mirror, adjust-
able for horizontal angles, mounted on the gun. The use of the
aiming rule will be described in detail later.

APPUCATION OF nNTTE AND INnNITE AIMING-POINT METHODS TO

RAILWAY ARTILLERY.

579. On the basis of methods of traversing and schemes of fire
control railway artillery may be divided into three classes:

Class 1 : Gims provided with traverse and firing from fixed or
semifixed emplacements on a straight track.

Class 2 : Gims provided with limited traverse and firing from
a curved track.

Class 3 : Guns having no traverse and firing from a curved
track.

580. Operation of Class 1 — ^The emplacements of such mounts
are so designed as to have satisfactory stability throughout the range
of traverse provided. It is obvious that nothing can be secured in

(;4r.

Plate 469

'=&

\^^^,^.&ONIOM£Ttlf 0RPW9RAMIC SiSftT

m-^e" MTWi STA/ces

M\M/SnN6 SCJ^HV^

>r»cr (/itme, smrAcePAMP hfoav^p)

^L^J " f^**! "

^^^J ^ ^ ■ ^^^J

■ ^1^ ^^ ^^ ^^

i

0=

SUr^OlfTtM^ PLATC

APJi/STABLC FOOT

AIMING RULE FOR USE WITH RAILWAY. ARTILLERY.

646

the way of traverse by moving the mount along a straight track.
Since the emplacement is assumed to have satisfactory stability,
there is no objection to the use of a finite aiming point. If OT,
figure 1, plate 470, is the plane of fire, and the aiming point is P,
and the deflection angle a is known, either from calculation or meas-
urement, the gun is laid in direction by setting off on the sight an
angle equal to a and traversing the gun until the vertical cross line
of the sight is on P. If it is desired to change the direction of the
plane of fire to OT', it is only necessary to set the sight at a new
angle equal to a minus h and to bring the sight again on the aiming
point P. The method of infinite aiming point is likewise applicable
to this class of artillery, and the writer recommends its use if time
permits. When the guns are operating at extreme ranges, and it is
not possible to observe the fire for accuracy, even slight displacements
of the emplacement may throw the plane of fire off the target. Dis-
placement of the emplacement does not have this effect when an
infinite aiming point is used.

581. Operation of Classes 2 and 3. — Guns which are provided
with car traverse usually have so little traverse that it is necessary
to operate them on curved tracks to cover a large target or to enable
them to operate on several targets. Guns which have no traverse
must of course always operate on curved tracks. Any mount which
must be operated on a curved track can not be operated with entire
satisfaction through the use of a finite aiming point. First, it is
inevitable that the track will- be displaced from firing, and, second,
it is quite probable that it wiU be necessary to operate on more than
one target from the same track. When a finite aiming point is used,
a displacement of the track involves a correction in the deflection
angle, and the calculation of this correction is laborious. Further, a
change of target with a finite aiming point, figure 2, plate 470, in-
volves a calculation in the determination of the new deflection angle
far more laborious than is required when an infinite aiming point is
used, figure 3, plate 470. Although angle e equals angle 6, figure 2,
there is no simple relation between angles a, J, and c, and the com-
putation of angle c becomes an entirely new trigonometric problem.
In figure 3 it will be seen that the determination of the new deflection
angle- c involves only the determination of the angle e. For, angle e
equals angle &; assuming M N' parallel to MN, angle e then equals
angle d, since angles h and d are equal, {h plus c — a — c plus d,)
The new deflection angle c therefore equals the old deflection angle a
minus the angle e,

582. Procedure in Detail for Sliding Mount on Curved
Epi. — ^Under the head of ''Procedure in preparing for action,^'
section 5, it was mentioned that in the instructions received by the
commander of heavy artillery to operate on a certain group of targets,

J

W7

Plats 470

AffWOPJ or PO/A/r/AfG /d9/LW/n^/?^/LLr/^r

Sr^/fiGHT Ti^/fCK

cui^y£i> £/^/

ng.n

ca^y^p en

Ft^.jU

648

the coordinates of these targets were given. From .these coordinates
the target may be located on a military map. On plate 471, T ia
one of the targets that has been so located. The artillery officer in
charge of that sector decides that a position in the vicinity of (r is to
be the firing position and the orienteur officer, having the location
of T and the approximate position of G, proceeds with the prepara-
tion of the data required for the construction of the epi curve as
follows:

583. In general, one can' see from any spot in France several
prominent objects, church spires, monuments, etc., the exact loca-
tions of which are given in coordinates on the military maps; M,
plate 471, is one of the points which the orienteur finds within view
of G. Assuming that the artillery to be used is of the sliding type,
class 3, the center and radius of the desired curve, the firing positions
on the curve for the various targets and the extent of the curve
must be determined.

584. From the approximate position of (?, the center 0 is located,
the radiua being given, and if possible a stake is placed at C. The
exact position of C is then determined from M and possibly other
known points in sight by triangulation. The position of (7 is located
in terms of the same system of coordinates as M and T. When the
position of C is known, the gisement of the line C T is determined
either from the map or by computation. With the length and gise-
ment of the line 0 T determined, the epi is constructed and the
various positions of C at which the gxm will be placed for operation
on the various targets are located, and the gisement of the various
gun target lines G T determined.

585. After G is located (on the outer rail), two other points 31
meters in front and 4 to the rear are located. Through these two
points a line is run which is extended to the rear a distance of 80
meters. At the end of this line the aiming rule is placed on two
iron stakes A and R, This rule is about a meter and a half long and
is normal to the G 0 line. Provision is made on the two iron stakes
for any necessary adjustments of the rule. The next step is to
determine the gisement of the normal to the aiming rule by means of
a goniometer moimted on the rule. After the gisement of this
normal is determined the value of the deflection angle 0 G T can be
computed. It is possible to compute this deflection angle in another
way, as follows: Knowing the gisement of the line C T and G 0 and
the value of the parallax angle C TG, it is possible to compute the"
deflection angle, corrected for wind and drift, by the use of Wilson's
correction board.

586. With the sliding type mounts it is not possible to operate
with satisfaction, using a panoramic sight and a distant aiming point.

649

I'lJlTK. 471

O^rr

}

DIAGRAM OF FIRE CONTROL OF SLIDING TYPE OF RAILWAY MOUNTS.

650

In the >eyent of lateral displacement of the track, which is inevitable,
the continued use of the same deflection angle and finite aiming
point does not by any means place the gun on the target. When the
aiming rule is used, the only effect produced by lateral displacement
of the track is the movement of the line of departure of the projectile
to a new path, parallel to the former path and a distance from it
equal to the extent of displacement, which may be only a few inches.

587. In action, the goniometer on the aiming rule is set normal to
the rule. A mirror may be substituted for this goniometer. The
goniometer on the mount is set at the corrected deflection angle.
The mount is moved along the epi by means of the translating
mechanism until the operators at the two goniometers G and 0 are
each able to see the shank of the other goniometer at the same time.
When this is possible, the gun is properly laid.

588. In the rapid determination of both the corrected deflection
and range, Wilson's correction board, plates 472 to 475, is an invalu-
able instrument. By its use a computation that may require as
much as an hour with possibility of error may be made with little
mental effort and little chance of error in less than five minutes.
This instrument determines the deflection, corrected for wind, drift,
and parallax. It likewise determines the range corrected for atmos-
phere, wind, powder velocity variation, variation in projectile
weight, and height of site.

589. Comments concerning certain of the above factors entering
into the correction of the range and deflection may be of interest.
With reference to the atmosphere, a certain degree of saturation ia
assumed by the French as a standard. The thermometer and barom-
eter readings then enable one to determine the density.

590. The air service of the Engineer Corps sends out every few
hours, by wireless, data on the ballistic wind. Their method of de-
termining the ballistic wind is as follows: Small balloons of a standard
size, about a meter in diameter, are inflated with hydrogen until their
lifting capacity is a certain amount. A balloon is released from a
certain spot which becomes an origin for later computations and the
position of the balloon is observed at regular intervals. From all of
these observed readings mean directions and mean velocities are com-
puted in terms of various elevations. The information that is sent out
is then: Elevation, X) velocity, Y; direction, Z; Y being the mean
direction of the wind for a maximum ordinate of X, This mean
effective wind for elevation X is called the ballistic wind. This data
is given for various elevations, so that the various battery commanders
firing guns with trajectories of different maximum ordinates will all
have the data they need.

591. The correction board already mentioned may also be used to
analyze certain results in the field. For example, if the range is X^

655

the corrected range Y, and the center of impact of the group of shots
is at a point whose range is Z, assuming, the wind, atmosphere, and
projectile weight factors to be correct, one may work back to de-
termine the actual powder velocity.

592. For the correlation of the observations of the terrestrial ob-
servers the deviation board, plate 476, is the best device. This board
was devised by Col. Pirie in France and later modified and simplified
to two sheets of paper and a triangle or T square, plate 477. The
board is an adaptation of the French system, which is as follows: A
sheet of paper is stretched over a plate of zinc and the point T, target,
is located about in the center, figure 1, plate 478. The positions of
the three observers, 0,, 0,, and O3, are then located accurately, either
on or off the board, usuaUy off. With these points as centers, two
arcs are drawn for each. A line through Oi and T locates zero for that
observer; the arcs are graduated on each side of zero; so also for 0,
and Oj. When the observers at these three points observe a burst it
is plotted as shown; e. g., 0, reports the burst 5 mils to the right; a line
is drawn through the 5-mil points on the two arcs whose center is O,.
Similar lines are drawn for 0^ and 0,, according to their reports. The
burst is supposed to be in the center of the resultant triangle.

593. In the French Army tjie aerial observer uses a photograph of
the region on which the target is located; this photograph is carefully
ruled in checker-board fashion. The observer locates the burst on his
photograph and reports the distance to the right, left, over, or under.
The battery commander plots these reports on a sheet ruled as in figure
2, plate 478. It will be noted that the up and down lines are converg-
ent; they pass through the battery position. It will be noted ako
that these lines are labeled both in yards and in angular units for the
quick translation of the observations. The horizontal lines are like-
wise labeled in terms of distances and angles. It may be well to
mention here that one car of the standard A. E. F. design, plate 479,
was fitted to serve as a fire-control car. Plans were made to supply
these cars for service in France, but on advice from France that they
were not desired the plan was abandoned.

181768—21 42

E DEVIATION BOARD.

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SECTION 7.

ASSEMBLY, DISPOSITION, AND MAINTENANCE OF RAILWAY

ARTILLERY IN LAND WARFARE.

594. It is intended to treat here the general problems of the care
of materiel that come up in connection with railway artillery. These
will be treated under the headings of assembly, disposition, and
maintenance.

595. Assembly.— -Ordinarily, railway artillery is shipped on its
own wheels, but in the case of the European war, all of that which
came from England and America had to travel by water and was, of
necessity, disassembled to a greater or less degree.

596. The experience of the English and of the American Navy
indicates that such mounts should be disassembled as little as possible,
and, in general, it was found possible to limit the subdivision to the
following:

1 unit, gun and cradle.

1 unit, main girder and carriage.

1 unit, each span bolster.

1 unit, each truck.
On the very heavy mounts, it was necessary to make a separate
load of the cradle. In all cases, also, the small and projecting parts
were removed and packed separately.

597. The importance of providing heavy pieces such as the girders
with proper lugs and rings for hoisting and handling, can not be too
strongly'emphasized. The designer often loses sight of this detail so
valuable to the men who are charged with loading and unloading
and assembling. As little work as possible should be left to be done
at the assembly shop ; in particular, drilling and riveting.

598. Particular care should be exercised in protecting bright
exposed metal surfaces before shipping overseas. In many cases
this was not done with guns and parts received in the present war,
and considerable time was lost in cleaning.

599. A careful study was made of the erection of the American
naval mounts and a summarv of recommendations with reference to

(663)

664

equipment and personnel is given below. The equipment should
include besides a full line of suitable hand tools:

(a) At least two, and better, three or four parallel and adja-
cent tracks at least 700 feet long for unloading and
erection.
(6) Compressed-air plant and distribution system.

(c) A locomotive crane of suitable capacity.

(d) Overhead cranes of suitable capacity.

(e) Three tool houses.

(f) Field shop and office.

(g) Office for Superintendent of Construction.
(h) Barracks.

The personnel recommended for this work includes :
(a) Commanding officer — ^major.
(6) Construction officer — captain.

(c) Adjutant, camp administration — lieutenant.

(d) Accounting and purchasing officer — lieutenant.

(e) 150 men, subdivided as follows:

19 checkers.

10 laborers, yard and camp.

3 laborers, warehouse.

1 chauffeur.
3 office force.
26 guards.

2 tool keepers.

3 orderlies.
3 mess.

1 latrine man.

15 expert mechanics.

58 railroad men — car and locomotive builders, track
men, etc.

3 extra men.
This arrangement was contemplated for the erection of a program
of six months. With an actual organization about the saqie,' a 14-
inoh mount was erected in 10 days.

600. Disposition. — In the British Army, the railway artillery is
classed as corps artillery and distributed as such. The plan followed
in the American and French armies is the one which would be
inferred from section 2, "The Scope of Utility of Railway Artillery,''
and section 5, "Procedure in Preparing for Action." This artillery
is too valuable, too expensive, and too slow in building to be used
except as necessity requires. It is felt that there is no merit in
keeping the pieces located in various positions along the front on the
theory that they would probably be needed in those localities.

665

Railway compauiee do not purchase a number of locomotive cranes
and place them at short intervals along the line for chance emer-
gencies. The cranes, as well as the railway artillery, are so mobile
that they can be quickly transferred wherever needed, and, when
not needed, are kept where thej^ are both out of the way, well pro-
tected, and easily maintained. The British scheme of corps railway
artillery is felt to have resulted in very poor economy in the utiliza-
tion of this mat6riel.

601. In the case of the French and American Armies, a certain
camp, about 30 miles behind the lines, was established for both the
materiel and personnel of the railway artillery. In the yards of
this camp were found the moimts and aU rolling-stock equipment.
At this distance behind the lines it is comparatively easy to main-
tain the personnel of the groups and not in any way to draw upon
the facilities required to maintain the personnel at the immediate
front. This camp was likewise on a well-established railway line
and all supplies could easily be secured. This plan worked out
well in both Armies.

602. Inspection. — Inspection of railway artillery is carried out
in different ways by the different armies. In the French Army
the inspection service is under the Commission A. L. V. F. (heavy
railway artillery). Regular inspections are made at considerable
intervals and routine notes are taken on condition of materiel.
Upon the occurrence of any accident a member of the inspection
service is at once sent for to render an opinion as to what should be
done. Such records as were seen of the French gims were quite
general in character. .

603. In the British Army the inspection service is under the
Ordnance Corps. It makes regular and special inspections, in the
same manner as the French, but more frequently and in greater
detail.

604. In the American Army the inspector was detailed from the
Ordnance Department, but his line of authority was not clearly
defined, and efforts were made to bring him under the authority,
respectively, of the Railway Artillery Reserve (the opera ting. branch),

* the Ordnance Repair Shop (the maintenance branch) and the

Engineering Division of the Ordnance Department (the technical

. and designing branch). A final arrangement was never worked out.

605. As a result of observation and experience, however, it is
felt that the inspector should, of necessity, be free from the authority
of the artillery commander, whose use of the guns the inspector's
work is expected to keep within proper bounds, and likewise free

.from that of the officer in charge of maintenance, whose work the
inspections should constitute a check on.

666

606. It is felt that the arrangement employed in the French and
British Armies, where the inspector is responsible solely to the
Technical and Design Service, is the proper one. Inspections
should be frequent and thorough and adequate records of each
piece of materiel should be kept. As an illustration of what it is
felt is required in this connection, an abbreviated copy of the Rail-
way Mount Service Book, as made up for the use of the American
Army, is given on the following pages.

607. Text and Outline of Railway Gun and Mount Service
Record.

[Cover.J
RAILWAY GTTN MOUNT SERVICE RECORD.

MOUNT.

Model

Number

Mark

PREFACE.

Railway artillery is coniparatively new to all armies, and especially so to the Army
of the United States. In conse^juencc, many difficulties have been experienced in
the manufacture of railway artillery materiel, and considerable delay has been en-
tailed by the necessaiy study of many unfamiliar details.

Similar difficulties and delays in the future can be minimized by studit^s based
upon current experieoco. To make this study complete, it is necessary to check the
theoretical knowledge of the designer by the practical experience of iiel.i personnel;
to know whether /he various parts fimction properly; and if not, why not.

While the records desired are more elaborate than those heretofore requested of
battery commanders, the arrangement of the book is such &s to make it a convenient
means of recording the desired information. Ample spact«, under descriptive head-
ings, are provided for information concerning practically every principal part of the
carriage; difficulties experienced, obeermtions, recommendations, and explanatory
sketches.

Only the conscientious cooperation of the ])«ittery commander in furnishing complete
data will enai)le the designers to produce the nearly perfect machine that the field
personnel would like to have.

TABLE or CONTENTS.

Page.

Instructions T 4

Record of assignment of mount 6

Daily gun record 6

Information in detaU—

Table and index 53

Notes and sketches 67

Forms of report of premature 137

INSTRUCTIONS.

This book is always to remain with the mount, and is never to be removed except
for the purpose of making entries, after which it is immediately to be returned to its
proper place on the mount.

667

Entries. — The entries are to be made at least once every 24 hours, when the mount
is in service, by the gun commander, under the supervision of the battery conunander .

Record of amgnment of mount. — ^The entries indicated on this page will be made
immediately upon receipt of the mount.

Daily gun record. — In this section of the book, under the respective headings, there
will be entered the number of shots fired, proportional weight of powder charges,
type of sliell, type of fuse, range, and elevation. In the colimm headed ' 'Remarks,"
there will be entered short notes, such as a note of an inspector's visit, damage to gun
or mount, nature of work the gun is used for (i. e., counterbattery, interdiction, or
deslruction), date sent to or received from the repair shop, date of transfer to another
battery, and other short items with reference to any detailed entries on other images.

Information in detail. — The table under this head indicates the desired information
concerning each principal part or group of parts, but is not intended to limit the in-
formation furnished. This should be entered on the blank pages following the table
and should include all available data as to poor fimctioning, weaknesses developed,
wear noted, changes suggested, etc. Make these entries as soon as difficulties are
experienced or defects noted. Sketches are of great value and should be a feature
of such entries. Before an entry in this section the number of the page on which it
is to appear should be entered in the index pertaining to the part or group concerned.

Reports of prematures. — ^These are to be made on the blank forms boimd into the
back of the book. They are to be rendered in accordance with the instructions
printed thereon.

Record of Absionhent of Mount.

MOUNT.

Model

Number

Mark

Date.

Gun cali-
ber.

Model.

Modifica-
tion.

0

Number.

Battery.

Regiment.

Battery comman>
der.

Oun:

Caliber

Model

Modification.
Number ,

Daily Gun Record.

Mount:

Model....

Number..

Mark

Number of shots.

Size of
powder
charge.

Date.

Full
change.

Reduced
charge.

eof
slfell.

Type of
fuse.

Range.

[47 pages of this form to be inserted.]

668

Information in Detail.

On the pages following thin table there will be entered full data concerning faulty
functioning, weaknetses developed, lindue wear, etc., with recommendations and ex*
planatory sketches. The table indicates the miture of the desired information con-
cerning the principal parts of groups, and will serve as an index to the entries. Make
entrips as soon as a fault becomes apparent, and index them in the designated spaces
below.

Part or group.

Gun :

Breech mechanism

Firing mechanism

Cradle

Elevating mechanism

Traversing mechanism

Recoil

Recuperators

Carriage

Bights

Main girders and transoms

Truck and frames

Translating mechanism. . . .
Jacks

Bolsters

Brakes

Outrigger

Firing beams

Loading mechanism

Power unit

Epis

Transbordeur

Ammunition car

Ground platform car

Ground platforms

Narrow-gauge equipment. .

Other cars

Other equipment

Index.

Information concerning—

Page

Wear of bore, shifting of hoops, and all other in-
formation conoeming tube, hoops, or Jacket.
Give model, modification and number of gun,
and date of entry.

Condition of obturatpr, replacement of parts,
wear action, etc. Give model, modification
and number of the gtm, and date of entry.

Difficulties experienced, observations and sujaes-
tions. Give model , modification and nmnber
of gun, and date of entry.

Condition and operation of all parts of cradle.
Give date of entry.

Diflficulties, slowness, jamming, etc. Give date
of entry.

Details of any difficulties, notes as to keeping on
targets, etc. Give date of entry.

In the case of spring recoil, renewal of springs, of
oil,etc.; case of sliding mounts, action of recoil,
treubles, suggestions, etc. Give date of entry.

Operation, leakEige, renewal of oil and air,
troubles, etc. Give date of entry.

Traversing rollers, trunnions, bearmgs, antifric-
tion device, etc. Give date of entry.

Adjustments, troubles, causes, suggestions.
Give date of entry.

AH details of interest. Give date of entry

All details of i nterest. Give date of entry

Action and condition. Give date of entrv

Action, rapidity, troubles, etc. Give date of
entrv.

All details of Interest. Give date of entry

Action , wear, and general condition. Give date
of entry.

Rigidity of mount, rapidity of mount, rapidity
of setting, bending, etc. Give date of entry.

Details as to wear, etc. Give date of entry

Rapidity, ease of handling, and suggested im-
provements. Give date of entry.

Reliability, power, and other points of note.
Give date of entry.

A 11 details of interest. Give date of entry

Points pertaining to operation. Give date of
entry.

Condition of contents, ease of handling, etc.
Give date of entry.

Details as to ease ofhandling contents, etc. Give
date of entry.

Rigidity, time to set, wear, suggested improve-
ments^ etc. Give date of entry.

All details of interest. Give date of entry

All details of interest. Give date of entry

All details of interest. Give date of entry

Page.

Page

Pag«.

[Faint ruled, both sides, with horozontal and vertical lines 5 millimeters apart,
for entry of information in detail, 81 pages.]

669

Battert Commander's Report of Prematures with Guns, Howitzers, and

Mortars, 37-mm. Caliber and Above.

Organization Date of report 19. .

Gun, howitzer, or mortar Caliber Model

Date of premature 19. . Rounds fired to date Rate of

fire Rounds per min. for mins. before accident. Did projectile

burst inside or outside the bore? Distance from muzzle

Color of smoke observed: Bl&ck Gray White

TYPES AND markings OP AMMUNITION.

Taken from round fired, or next of same lot?

Fuse: Type Model Shape head

Color head Color body Lot No

Projectile: Type Model- Color ogive Color

body Stamped markings Lot No

Cartridge case: Stamped markings Lot No .'

Propellant: Type

Weight

Normal •

Reduced Zone No

Bag markings

EXAMINATION OF FRAGMENTS OP PROJECTILE AND FUSE.

Did explosive adhere to fragments? How?

Edges: Sharp, square, or melted? Smoke blackened or heat blued?

Fragments: Large or small? Where found?

Remarks:

[Pages 137 to 144 will be duplicates of this copy, but will not bear folio No. ; they
will be perforated i inch from the hinge.] *

INSTRUCTIONS.

Original and two carbon copies of this report will be made by the battery commander
as soon as practicable after the premature occurs, and will be sent direct to the Chief
Ordnance Officer of the Army. Details concerning abnormal or short rounds should be
noted under '^Remarks".

(Signed)

Battery Commander.

608. Maintenance. — ^The discussion of railway artiQery must, of
necessity, be very incomplete, but an effort will be made to enumerate
the chief matters which have come to the writer's attention in connec-
tion with it. First, cannon and then mounts will be considered and
the types of wear and breakage and the methods of repair will be

670

discussed. Then shop equipment and organization for taking care of
maintenance will be set forth.

609. Cannon. — ^The chief difficulties requiring maintenance in con-
nection with cannon are derangement of breech* and firing mechan-
isms, coppering of bore, bursting and swelling of tubes, and wear.
The derangements of breech and firing mechanisms are merely small
mechanical difficulties, the caring for which requires only a supply of
spare parts and small size machine-tool equipment.

610. Coppering of the bore from rotating bands is a very serious
difficulty. On the 14-inch Navy guns, after about 200 shots, this
deposit of copper had reduced the range 5,000 yards. A most satis-
factory, method of remedying and of preventing this coppering, has
been devised and used successfully in the French Army. This con-
sists in introducing into the powder chamber a tin-lead alloy, which
melts on firing and combines with the copper on the gun to form a
brass, which no longer adheres as before to the interior of the bore.
This process may be carried out best by attaching the alloy to the
•base of the projectile, by dipping, spraying With a metalizing pistoL
or soldering on a disk of the metal. The introduction of foil of alloy
into the powder bags appears to be satisfactory for small calibers, but
does not give satisfactory results in large calibers.

611. Bursting and swelling of the tube are due to premature ex-
plosions of H. E. shells. French records show that such accidents
occurred on an average of once in every 32,000 rounds with the 75's
and once in every 14,200 rounds with the 155 Filloux guns. Such
guns are usually discarded, but a process devised by Col. Canoniea, of
the ItaUan Army, is in use in Italy for reclaiming such material. This
process consists of selecting two ruptured guns, in which the break is
at different ends, cutting them in two and screwing the two good
halves together. The threads are obtained by turning down the end
of one part and boring out that of the other, each for about half the
thickness of the metal .and for 8 inches of length. Threads are cut
very carefully so that the rifling matches when the two pieces are
screwed home. Finally a ring is shrunk on outside' the junction.
This scheme has been used successfully on a considerable number of
149-millimeter cannon.

612. Wear, however, is the great and important problem in the
maintenance of cannon. Care in cleaning of projectiles, faithful use
of anticoppering methods, etc., may assist, but every gun will sooner
or later wear so much that its range and accuracy are reduced below
the economical limit. This wear occurs at the breech and muzzle
ends principally, and consists in a gradual eating away of the rifling.
At the breech end, this occurs more or less evenly around the cirfcum-
ference and is thought to be due to the intense heat of the burning
powder gases which are projected against the forcing cone, as they
follow the projectile. This wear causes the so-called " advance of the

671

forcing cone," i. e., the projectile must be pushed further and further

toward the muzzle before it will seat properly in the rifling. The re-

ult is an enlargement of the powder chamber, a change in the density

' loading, and a corresponding change and uncertainty as to muzzle

>city. The use of rifled projectiles, previously described, is de-

*d to eliminate the necessity for a forcing cone, to allow a powder

ler the same size as the bore, and so to eliminate as much as

' of this wear. At the muzzle end, the wear is confined almost

to the rear edge of the lands, the edge which does not press

ist the rotating band. It is thought to be due to the mechanical

. osion of the very high velocity gases which leak through the small

orifice. This wear destroys the rifling progressively from the muzzle

back to the breech and results in greater and greater dispersion of the

shots.

613. The life of guns is given in a number of instances in the tabu-
lated information of section 10. The figures there given for French
guns in Volume II are from actual experience. From this experience
the following formula for determining the life of large caliber guns has

been developed:

2 5 X 10'
Life in rounds =p x D x {D -2) P'

where V = muzzle velocity in feet per second divided by 1,000.

D = caliber in inches.

P = maximum powder pressure in long tons per square inch.
The guns from which this formula was derived are nearly all very
old models, and few, if any, had the advantage of the sort of care in
firing that has now been discovered to be advisable. It is felt from
isolated instances which have been compared with this formula, that
a large gun operated with cleaned projectiles, and proper decoppering
methods, should have a life at least 50 per cent in excess of that in-
dicated by the above formula.

614. The methods available for the repair of worn-out guns are:
(a) Rechambering.

(6) Reboring.

(c) Relining.

id) Retubing.
Rechambering consists of machining out the forward end of the
powder chamber until the eroded metal is removed and a new forcing
cone is formed. The piece is then supplied with a large powder
charge, so arranged as to give the same muzzle velocity, and a con-
siderable additional life, perhaps 40 per cent, may be obtained.
This method is applicable only to guns, as they wear out at the
breech end first, while howitzers wear about evenly at breech and
muzzle ends. The advantages of this method are the simplicity with
which it can be carried out and the very good results obtained. The

181768—21 43

672

disadvantages are the fact that it adds only fractionally to the life of
the gun, that it is inapplicable to short pieces, and that it requires a
special powder charge for such guns as are repaired by it.

615. Reboring consists of tiuming out the entire interior of the bore
to a large diameter and rerifling. This necessitates the use of a dif-
ferent caliber of ammunition, and of a lower powder pressure and
muzzle velocity, reducing the range, in some ca^es, materially. The
life should be almost as many rounds at the new caliber as at the old.
The advantages of this method are that no forging equipment or
shrinking arrangements are necessary, and that the life of the gun
is doubled. The disadvantages are the reduction in range and the
necessity for using a different caliber of ammunition.

616. Relining consists of turning out the interior of the bore to a
larger diameter and inserting a liner, in which the rifling of the origi-
nal 'Caliber is cut. This liner is usually inserted by shrinking the gun
over it, but the method of autofrettage or expanding the liner into the
gun by hydraulic pressure is also being developed. This method is
probably inapplicable to small calibers on account of the thinness of
the liner that would have to be used. The advantages of this method
are that it requires a fairly light forging and that it gives a gun prac-
tically as good as new and using the same ammunition as the old one.
The disadvantages are the forging facilities required, the length of the
process, estimated as nearly 900 hours on the United States 12-inch
gun, and the fact that there is considerable doubt about the possibility
of rechambering relined guns.

617. Retubing consists of disassembling the gun and building it up
again around a new tube, just as it was built up at first. This, of
course, gives a gun in every way as good as new. The disadvantages
are, of course, the great amount of forging and shrinking equipment
required, and the length of the process.

618. Mounts. — ^Wear and tear on railway mounts are of the same
character as take place on railway rolling stock and seacoast gun
carriages. Breakages and derangements are of a purely mechanical
character, and generally of fairly minor magnitude. Repairs require,
principally, a well-equipped machine shop, and no detailed discussion
of them is called for.

619. Organization and Arrangements for Maintenance. — In
the British Army the maintenance shops for railway artillery were
under the command of the ordnance officer at the base at Calais. In
the French Army they were under the chief inspector of artillery, for
fairly light repairs. Major repairs were made at the works of the
Schneider and other private corporations. In the American Army
the exact arrangement was never finally fixed, but to all intents and
purposes, the repair shops for railway artillery were under the com-
manding general of the railway artillery reserve. It is felt, as a
result of observations of the workings of these various svstems. that

673

the shops should be directly under the control of the engineering
division of the office of the chief ordnance officer. They should
not, of course, be under the inspection service, but should be coordi-
nate with it and under the same authority.

620. In the French Army most of the enlisted personnel required
for the operation of the shops was assigned permanently and was
not drawn from the various groups of artillery stationed near them.
There were about 80 workmen permanently attached to the shops.
These, with the four artificers attached to each battery, are easily
^ble to handle the maintenance of not only all of the railway artillery
of the French Army but likewise of a great amount of field artillery.

621. One feature which strikes one most forcibly in both the
French and British repair shops is the evident skill of all the men.
One does not see in any American shop the type of men used in these
shops. The captains found in charge of all the shops were of the
type of the highest caliber shop manager in America. These men
are not only men of a great deal of shop experience, but high-grade
graduate engineers. It is estimated that their average age is about
45 years. Tne use of such men as these in these positions is in the
highest d^ree necessary.

622. Location and EkjuiPMENT of Shops. — The scheme of dis-
position of inactive artillery just discussed makes the problem of
maintenance a very easy one to solve in a very satisfactory fashion.
In the yards of the camp where the railway artillery is mobilized,
shops of the desired degree of permanency are built and equipped to
handle all except the serious and most extensive of the maintenance
work. Cars damaged very seriously by shell fire, or guns which must
be relined or retubed must of course be sent back to the manufacturer
or to the biggest base shop. In the French camp, the shops are well
built brick structures of the type that one ordinarily finds used for
medium heavy manufacturing. In the American camp the shop
was similarly constructed, but was a steel frame building covered
with corrugated iron.

623. The equipment of the French shops is about as follows:

2 24-inch lathes with 10-foot bed.

8 smaller lathes, about 12 by 72 inches.

2 horizontal milling machines.
4 shapers.

1 high-pressure air compressor for filling recuperator air

bottles.
1 vertical boring mill.
Oxyacetylene welding and cutting outfits.

3 large forges.

Portable forges.
1 drop hanmier.

674

1 portable air compressor for use with air tools.

1 circular saw.

2 band saws.

1 50-ton shop crane.

A good vise and bench for every man in the shop.

624. The equipment of the American shop was about as follows:

8 lathes, 8 by 12 inch swing.

1 lathe, watchmaker's.

6 grinders.

2 shapers.

5 drill presses, up to 20-inch radius.

3 screw machines.

1 planer, 8 to 12 foot bed.
1 power hacksaw.

1 power cold saw.

2 band saws.

1 Landis bolt machine.

2 300-foot air compressors.

1 welding and cutting outfit.

2 10-ton bridge cranes.

625. Experience with the American shop leads to the recommenda-
tion, slightly modified from that submitted by the conunanding officer
of the shop (38), that an equipment about as follows is necessary:

10 lathes, sizes from toolmaker's to 26-inch by 16-foot.
2 turret lathes.

1 planer, 48-inch by 16-foot.

2 shapers.

7 grinders, tool, cylinder and surface.
5 drill presses, 5-foot to high speed,

4 power saws, hack, cold and wood.
2 milling machines.

1 power hammer, 6-inch stroke.

1 heavy straightening press.

1 planer and joiner.

1 boring and mortising machine.

1 48-inch wood lathe.

1 brass cupola.

4 oxyacetylene cutting and welding outfits.

1 air compressor, 300 cubic feet, air tools.

1 150-ton bridge crane with 10-ton auxiliary.

1 10-ton high-speed crane.

1 150-ton locomotive crane.

1 15-ton locomotive crane.

1 4-foot bulldozer.

1 screw punch, 1-inch hole in J-inch plate.

2 jib cranes, 2i tons capacity.

675

626. With all these facilities provided, it has been found unneces-
sary to carry more than a few tools to the front with the mounts,
i. e., anvil, portable forge, oxyacetylene outfit, hammers, chisels,
brace and bits, drills, files, etc. No special repair car is employed
in either the British or French armies, and neither organizations felt
it to be advisable. A standard A. E. F. box car was fitted to serve
as a repair car, plate 501, but the plan tp provide them for service
in France was abandoned. One was used to good advantage at the
proving ground.

627. In the same way, practically all spare parts are carried at the
shops in the main railway artillery camp or camps. The only spare
parts carried with the mounts are for the firing mechanism, some
bolts, screws, and miscellaneous stock. Such a car would be wasted
unless the alterations or provisions made in it to carry spare parts
would not interfere seriously with its use for something else. It
surely would not be used to carry spare parts.

DUTIES OF THE RAILWAY ARTILLERY ORDNANCE OFFICER

628. Although the following material, which was prepared by the
writer, is given in another publication as noted above, it seems wise
to give it here also in order that all material that has any reference
to railway artillery may be contained in these two volumes. The
foDowing paragraphs will repeat information already given, but
are included herein without modification just as they are given in the
Ordnance Field Service Manual.

[Exact copy of Chapter X of Ordnance Field Service Manual (39).]

DUTIES OF THE RAILWAY ARTILLERY ORDNANCE OFHCER.

629. ^*Before proceeding with an enumeration of the duties of an
ordnance officer of railway artillery, a brief explanation will be given
of the organization and functions of what may be termed a ^ * Railway
Artillery Reserve," as it is at present understood.

630. Railway artillery in combatant service is quite analogous to
the wrecking service of any railway organization. By this it is meant
that although it is a definite part of the combatant organization as a
whole, it is not a part and is not under the jurisdiction of the organ-
ization of any one army. The term ''reserve'' is used to imply that
it is a branch of artillery not in use in daily routine service on the
front, but is held in reserve at a central point for that peculiar and
special type of work for which it has been designed and is peculiarly
fitted. The point at which this artillery is held in reserve is known
as the "Camp of the Railway Artillery Reserve," and may be con-
sidered to a certain extent in the light of a permanent camp. This
camp accommodates during all of the time that it is not in active
service not only the artillery itself, but the entire artillery personnel.

676

It includes, likewise, the heavy semipermanent railway artillery
repair shop, general equipment, ammunition and spare parts depots,
and a proving ground for the calibration of ammunition and proving
of guns. The ammunition used by this artillery is not used by any
other type of artillery, and it requires, in general, special facilities
to handle it.

631. From the above brief explanation, it will be seen that the
functions of the railway artillery ordnance officer are, as far as they
concern the general equipment depots, quite analogous to those of a
camp ordnance officer. The functions, with reference to the admin-
istration of an ammunition and spare part depot, ammunition inspec-
tion service, and artillery inspection service, are analogous to the
functions of the Army ordnance officer. The functions with refer-
ence to the artillery maintenance service are peculiar to this type of
service.

632. The railway artillery ordnance officer will be qualified as an
adviser on all technical ordnance matters, including the effects of the
various calibers and types of artillery for any specified work. Acting
under the supervision of the proper staff sections, he is responsible for
the efficient service of ordnance supply and maintenance, including
inspection and repair work in the Railway Reserve, and supervises
and coordinates this work. He exercises general supervision and
control of all ordnance supply, repair, inspection and maintenance
work, and facilities within the Railway Artillery Reserve in so far
as technical matters are concerned, and is in direct control of supply,
repair, inspection, and maintenance of the artillery. He makes, or
causes to be made, such inspection of ordnance materiel and repair
and maintenance facilities as he may consider necessary and permits
no alterations in ordnance equipment without the authority of the
chief ordnance officer, excepting in emei^encies. He causes periodic
inspection to be made of all storage facilities under his jurisdiction
and sees that proper practice is observed in storage, particularly that
ammunition is properly cared for and maintained, and that the nec-
essary technical information is available.

633. He maintains such records as enable him to keep the com-
manding officer of the Railway Artillery Reserve fxilly informed as
to the condition and sufficiency of ordnance materiel, all repair and
maintenance facilities under his jurisdiction, and the condition of all
ammunition. • He makes such technical reports and keeps such rec-
ords as are required of him by the commanding general of the Rail-
way Artillery Reserve, by the chief ordnance officer, and by higher
authorities. He is authorized to correspond directly with the chief
ordnance officer on questions in which the policy of the Railway
Artillery Reserve is not involved. He causes to be carried out such

677

technical instructions for repair, maintenance, and alteration of
ordnance materiel as may be prescribed by the chief ordnance officer.
634. There are assigned to the railway artillery ordnance officer as
assistants the following officers with their necessary commissioned
and enlisted assistants for the operation of the services mentioned:
Supply officer and artillery armament officer. The accompanying
table shows the organization of railway artillery center for approxi-
mately 300 guns:

Ordnance pergonnelfor railway artillery center for approximately SOO guns.

1

2

8

4

5

0

7

8

9

\

Units.

Office of
R.A.O.O.

Supply warehouses.

1

Ad-
minis-
trative
oflloe,
2.

Gen-
eral
sup-
plies,
2.

Artil-
lery
and

parts,
2.

Am-
muni-
tion, 3.

Inspec-
tion.

Main-
te-
nance
Table
Ex-
hibit 1.

Totab.

2

Colonels

•1
*a2

S

Lioatenantooloneb

4

Ifajors.

♦52

3

•1

•1

1
1
2
2

5

Captains

♦«1

•«1

el

1

6

Itrst lieutenants

«1

1

7

Second lieutenants

1

Total commissioned

Ordnance sergeants

8

4

2

2

1

2

♦/3

8

24

9

2

e"

3

2

1
2
4
1
5
20

1
1
2

4

1

6

10

2

2

4

10

2

10

50

*fS

9

22

10

Sergeants, first class

5

11

Serieants

42
42'

25
31
2
48
16

42

12

Corporals .

*J2

58

13

Cooks

6

14

Privates, first class

2

4

74

U

Privates

100

Total enlisted

16

4

17

35

24

80

10

131

307

Acsrecate

17

8

19

37

35

88

23

137

r33I

4 5-pasBenger cars.

3 motor cycles with side cars.

2 ^ton truclcR.

2 3-ton trncln.

18
19
20
21

4

SirKBKKCE.*! FOB rRECBOmO TABLB.

o 1 artill<*ry armament officer, 1 supply officer.

f» I artillery inspector, 1 ammunition inspector.

c Administration assistant.

d I field inspector, 1 proof officer, 1 assistant to armament officer.

« In charge of sections.

/ Technically trained assistant.

g Clerics.

* Chief clerk.

i Stenographer.

> Permanent personnel, clerks.

s Headquarters section and two platoons of an ordnance depot company.

' Two platoons of an ordnance ammimition company. Table 242.

r To be armed with rifles or pistols only wtien deemed necessary by commanding officers.

635. The administrative assistant in the office of the railway
artillery ordnance officer is a captain. He is charged with the duties
of maintaining the records of the entire ordnance personnel, both
commissioned and enlisted, and with the proper keeping of office

678

records. He is authorized to make all emergency purchases, being
appointed an agent officer for this purpose.

636. The supply branch is in charge of a lieutenant colonel, who is
the supply officer of the Railway Artillery Reserve. He is charged
with supplying equipment to troops and ammunition and spares for
artillery. He requisitions for equipment, spares, and stock direct
to the Chief of Ordnance of the Ariny if in the zone of the interior, or
to the chief ordnance officer if in the theater of operations. He
requisitions for equipment both regular and special in anticipation of
demands to be made on his depot. He may requisition by telegraph
when stores are urgently needed for the equipment of any troops, or
the replacement of lost equipment, or for instruction purposes.

637. When an automatic supply of stores has been ordered in
anticipation of the needs of the troops in the camp of the Railway
Artillery Reserve, the supply officer keeps in touch with the supply
and requests its expedition when necessity arises.

638. Supply officers of the various organizations located at the
camp of the Railway Artillery Reserve requisition for items of
ordnance property needed by the troops of their units, these requisi-
tions having the approval of the organization commanders. These '
requests will be sent directly to the railway ordnance officer.

639. The supply officer has commissioned assistants in charge of
administrative, general supplies, artillery and artillery . parts, and
ammunition sections.

640. The administrative assistant is charged with the accoimt, and
record work necessary in the office of the supply officer.

641. The officer in charge of the General Supply Section is charged
with the receipt, storage, and issue of all ordnance stores except
artillery and ammunition.

642. The officer in charge of the Artillery and Artillery Parte Sec-
tion is charged with the rpceipt, storage, and issue of all material
classed as railway artillery and spare parts thereof.

643. The officer in charge of the Ammunition Section is charged
with the receipt, storage, jand issue of all ammunition, including the
loading of the special ammunition cars.

644. The assistants to the supply officer shall maintain such records
as are necessary to keep the supply officer informed as to the stock
on hand, the receipt, issue, and probable needs of general supplies,
artiUery and artillery spares, and ammunition. Similar blanks
specified for the ammunition parks of the Army are to be used by the
Ammunition Section.

645. The artillery armament officer is responsible for the inspection,
repair, and maintenance duties in so far as they pertain to artillery
and ammunition used by and in charge of the Railway Artillery

679

Reserve*. He maintains such records as enable him to keep the rail-
way artillery ordnance officer informed at all times as to the con-
dition of all artillery, its availability for service, the state of the guns
as to wear, etc. He will be prepared to furnish the railway artillery
ordnance ofBicer all necessary technical information on ammunition.
He is personally responsible for the field inspection of all artillery.
He specifies what repairs are to be made in the railway artillery
repair shop or in the field and passes on their satisfactory completion.
He will make periodic inspections of all artillery in the artillery park,
will be responsible for the condemna,tion of guns unserviceable from
wear or accidental damage, and will see that all field organizations
are instructed on the proper use and care of their material. He is
likewise charged with the administration of maintenance facilities
shops, etc., provided for such work as is hereinafter specified.

646. Inspection shall be made of all artillery at least eight or ten
times during its normal life. This inspection will consist of a visual
examination of the bores for coppering, pastilles, cracks, or other
injuries, the operation of the elevating, traversing and breech mechan-
isms, and the accuracy of the sighting mechanisms; it will also include
the questioning of the battery mechanics regarding the operation of
the recoil systems and the length of time between the renewals of
the recoil fluid and examination of the gun books.

647. A star gauge and a plug gauge record should be made at
least two or three times during the life of the gun, and gutta percha
impressions of any abnormal conditions, such as excessive wear,
unnatural erosion or swells.

648. The artillery inspector will make a final inspection of all
Repairs made in the artillery repair shop and is responsible to the
artillery armament officer that all field and shop repairs and main-
tenance are properly executed. He maintains such records with
reference to the condition of each individual gun, carriage, etc., as
enable him to inform the artillery armament officer of its exact status
with reference to its availability for service, the remaining life of the
gun, and of the characteristic field behavior of the gun and carriage.
He will supervise the proving of guns and carriages, the firing of
range tables, and the proving of improvised artillery accessories. He
will investigate and report upon all accidents chargeable to defects
in the artillery material. It is his responsibility to see that all tech-
nical investigation called for by the chief ordnance officer with refer-
ence to the behavior of the guns and carriages are properly carried
out, and he shall maintain his routine records with such thoroughness
and exactness as will assist to the maximum services responsible for
the design of the material.

649. The artillery inspector will be provided with one closed car
for field inspection service and one light repair truck for carrying of

680

inspection instruments. He will be provided with the following
miscellaneous equipment:

Star gauges suitable for the various calibers of guns.

Plug gauges.

Bore sights.

Gutta percha impression outfits.

Alidade.

Planimeter.

Steel tapes.

Micrometers.

One complete set of drawing instruments, including
Universal drawing instruments.

Flexible curve.

Complete set of Universal curves.

650. The ammunition inspector is responsible for the inspection
of all ammunition, storage and handling facilities, and will see that
safety instructions are complied with. He will make periodic ex-
aminations of the condition of ammunition both by visual inspection
in the storage house and by trial on the proving ground. He is
responsible for the furnishing of all technical information on am-
munition, both to the troops and to the artillery armament officer*
He will investigate and report upon all accidents that may be charge-
able to anmiunition, and will keep the artillery armament officer
informed as to the behavior of ammunition and any defects dis-
covered. He is responsible for the calibration of all ammunition as
called for by the conmianding officer, Railway Artillery Reserve.
He is responsible for the collection, examination, and report on
specimens of captured or unexploded enemy ammunition. He shall
maintain such records as will be of maximum service to those or-
ganizations responsible for the design and manufacture of ammunition
and he will conduct such investigations as may be called for by the
chief ordnance officer. He will be provided with a full set of drawing
equipment. Ideal drawing instruments, flexible curve and Universal
curves and beam compass.

651. The railway artillery maintenance officer is in charge of the
special railway repair shop and handles all necessary repairs and
general maintenance on all artillery and motor vehicles. He super-
vises the making of all modifications in artillery as specified by the
chief ordnance officer or required by field emergencies. He is re-
sponsible for the maintenance of such records as enable him to keep
the artillery armament officer informed as to the condition and
adequacy of all his facilities and the supply officer as to lus needs for
spare parts and raw materials. He is responsible for the making up
of any necessary designs for emergency equipment or replacements.
He'shall maintain such records as will be of maximum assistance to

681

the various ordnance design services with reference to the perform-
ance of the various designs of mechanisms and the materials used
therein.

652. Since the personnel of the railway artillery repair shop is
responsible for the maintenance of all artillery, it is the duty of the
maintenance officer to take under his charge the special mechanics
assigned to each battery while the artillery organizations are in the
park. These men will be used in the general maintenance service
and will be given such training as will enable them to properly main-
tain their artillery in the field.

SECTION 8.
EQUIPMENT FOR RAILWAY ARTILLERY.

653. Tables of Initial Equipment. — It is not intended in the
following to attempt to give definite rules for what should constitute
total accessory equipment for railway artillery. Certain general
recommendations will be made, however, which are based on French
and British experience and observations by members of the Ord-
nance Department in France. It is probable that these will be of
some value in the future (40).

654. A definite understanding was never reached between the
Ordnance Department in France and the Ordnance Department
in Washington with reference to the lists of equipment prepared in
France for the American Railway Artillery. The Engineering
Division of the Ordnance Department in France prepared lists
which included primarily items of equipment in use by the French
and British services, but which, due to different service conditions,
were not familiar to the Ordnance Department in Washington.
In addition, an attempt was made to complete the lists as nearly
as posvsible from the information received from Washington on
drawings, tables of equipment, etc. Only incomplete information
had been received at the time, however, with reference to the re-
quirements for the 8-inch gun and 12-inch mortar, for which the
tables were being made. The lists were consequently not con-
sidered complete, but were nevertheless forwarded to Washington.
It seems that this procedure led to some misunderstanding; o. g.,
items which had been left out for the lack of sufficient information
were, when the lists were gone over in Washington, assumed as not
wanted. It was hoped that, by combining the ideas of require-
ments as contained in the lists prepared in France, and the require-
ments necessitated by the particular type of mount worked up in
Washington, at least sufficient equipment would be provided. The
lists as they were prepared in France covered only the initial battery
equipment, to a large extent based on the equipment carried by the
French batteries.

655. Depot and Automatic Supply. — Neither the experience
of the French nor the British service was sufficiently extensive to
enable one to establish figures with reference to depot supply and

(683)

684

automatic supply. For this reason, and in order that an ample
initial supply might be furnished, the arbitrary amount of one com-
plete battery equipment for each three batteries was requested for
the initial depot supply. It was intended that after sufficient
knowledge had been gained with reference to rate of consumption,
certain items could be put on an automatic supply list. It was
feared that an arbitrary assumption of figures for automatic supply
would lead either to an excessive acciunulation of certain articles,
or to the supplying of insufficient quantities of other items. To
date no further knowledge has of course been gained on this subject,
so it is impossible to give any figures covering either the number of
parts to be kept on hand in a depot, or to be supplied automatically.
A close study of each particular moimt in the design office will lead
to fairly reasonable assumptions for requirement^ of spare parts.
In determining numbers of spare parts, it is certain that destruction
of parts by shell fire need not be considered.

656. Spare Parts, Tools, and Accessories Carried wrrp the
Battery. — ^Assuming that the railway artillery is operated from
one or more large camps or centers which are equipped to handle
all repairs except relining or reboring of guns, and extensive re-
building of damaged carriages, and assuming also that the radius
of operation is such that for any medium repair work not necessi-
tating the withdrawal of the mounts to the shop, they can be reached
by a mobile repair truck within a reasonable time, it is evident that
only a very limited supply of spare parts need be carried with the
battery. It is also evident that only a limited number of ordi-
nary repair tools would be required.

657. The system of operating railway artillery from one large
center is well established and highly recommended. The scheme
of handling medium repair work with repair trucks, while not tried
out to any great extent in connection with railway artillery, never-
theless seems to have many advantages. First, as mentioned above,
the quantity of repair tools and spares carried in the field with the
mounts can be considerably reduced; second, the number of skilled
mechanics can be limited to a great extent and utilized to much
better advantage on repair tiucks and in the repair shops than they
would be if permanently assigned to a battery. The tables of or-
ganization for railway artillery provide 28 enlisted ordnance men
per regiment of 24 guns. As railway artillery never operates in
units of regiments, these men, if kept with the guns, must be di-
vided between the six batteries. This of course results in an uneven
distribution of skilled and unskilled men. If, instead, the men are
kept at the shop which is provided with a sufficient number of re-
pair trucks, supply trucks, good automobiles and motor cycles, it is
obvious that any S. O. S. call from the front for repairs and spare

685

parts can be answered by picked men for the particular kind of
repairs required, and the best results obtained in the same or less
time. It is thought that one repair truck per group of eight guns
would be required on an active front. This discussion is largely
on maintenance, but it is evident that the quantity of equipment
which should be carried is a direct function of the scheme of main-
tenance employed. Assuming that the repair-truck scheme is
adopted, the following recommendations for equipment to be carried
in the field are made. As the equipment will of course vary with the
type of mounts, the recommendations must be considered very
general.

658. Tools and accessories recommended —

A. Tools and material required to make emei^ncy track repairs:

1. Standard trade tools.

2. A few pieces of raU, bolts, spikes, and fishplates.

3. A few standard ties.

B. Tools. and accesBories for operating train:

1. Lantern, lamps, ftigs, etc.

2. Car pusher and replacer.

C. Tools, accessories, and material for emplacement.

This will, of course, vary with the different types of mounts and can very
eaEdly be determined. The material and items constituting platforms, out-
riggers, etc., should be ample in regard to spares if easily broken or damaged.

D. Tools, accessories, and parts for gun and breedi.

In determining the spare parts to be carried with the gun in the field, it
should be kept in mind that only such parts as can be eaaly replaced should
be considered; as, for instance, firing mechanism and firing pins, a few extra
bolts and nuts, washers, packing, springs, cotterpins, etc. It should also be
kept in mind that, besides adding to the weight which is hauled around
unnecessarily, a good deal of time is consumed in taking care of parts which
seldom will be required, and could better be cared for in the depot.

E. Tools, accessories, and spare parts for carriage and mount.

The statement made under D applies to this section. Such articles as journal
bearings, brake shoes, air-brake hose, brake pins, and cotter pins should be
carried in small quantities. It does not seem necessary to carry spare couplers
and buffers, however, it may be advisable to carry a limited number of emer-
gency knuckles.

F. Jacks, cordage, blocks, etc.

Only such jacks should be carried as demanded by anticipated difficulties,
as, for instance, the need of auxiliary jacks for raising the car for the 12-inch
mortar. A good supply, about 200 feet per gun, of l}-inch rope and about
200 feet of }-inch rope should be kept on hand, and two sets of double tackle
blocks for 1^-inch rope. One spare triplex block with chain of capacity used
for loading cranes. Twine packing and whipping and tarred hemp yam, }-inch,
should be carried in ample quantities.

G. Carpenters' tools: Per battery.

Axe 1

Augurs — ^

Screw, solid, wing-eyed, l^-inch 1

Screw, solid, wing-eyed, 1 -inch I

686

G. Carpenters' tools — Continued.
Bits, twist—

1-inch ,

i-inch

i-inch

J-inch

Brace, ratchet, for bits

Chest, tool, carpenter's

Chisel, wood —

l^-inch

1-inch

i-inch

Mortising

Gouge, 1-inch

Gouge, 1-inch

Dividers, 8-inch

Drift, steel, round, }-inch

Gimlet —

}-inch

1-inch

Hammer, claw

Handles —

Augur, 16-inch

Saw, crosscut

Hatchet, wood handled

Mallet

Oil stone, } by 2 by 8 inches.

Pencils, carpenter's

Pinchers, pair

Plane, jack

Rasp, wood —

Flat

Round

Rules, folding, 6-foot. . . :

Saw —

Hand, rip, 36-inch

Hand, crosscut, 26-inch

Blade, 5-foot, with handles

Square, combination, 8-inch blade

H. Machinists' tools:

Chest, tool, machinists'

Chisel —

Cape, steel

Cold

Dividers, spring nut, 6-inch, pair

Drill, breast, with chuck

Drill, twist, straight shank, Morse original, for breast drill-

f-inch

A-inch

1-inch

iVinch

1-inch

A-inch

• . 687

H. Machinists' tools — Continued.

Drill, ratchet

Brills, for ratchet drill, twist

i-inch

i-inch

i-inch

1-inch

Emery stick, fine

Files-
Flat bastard, 12-inch

Round bastard, 12-inch

Square bastard, 12-inch

Flat, second cut, 10-inch ,

Round, smooth, 10-inch

Square, smooth, 10-inch ^

Taper, 8-inch

Hammer, machinist, ball pein, 1} pounds

Handles, file, assorted. . ^ 12

Jaws, copper, for bench vise, pair :

Oiler, machinist's, small. . . - ,

Pin, drift, 1} by 1 inch

Punch, center

Saw, hack, adjustable 2

Saw, hack, 12-inch blades 36

Scale, steel, square combination

Vise, bench, about 4-inch jaw '. <.

Wrenches, monkey —

6-inch

12-inch

18-inch

I . Blacksmith's tools:

Anvil, 100 pounds

Borax, pounds

Chisel, hot, 2-inch blade

Forge, portable, "Buffalo," 24 by 30 inches, with tank

Hammer, blacksmith's, 1} pounds, with handle

Hanmier —

Sledge, 10 pound, with handle

Set, 1 J pounds, with handle y . . .

Hardie, 2-inch blade, 1-inch handle

Punches, blacksmith's —

j-inch

J-inch

Swages, pair —

J-inch

}-inch :

1-inch

li-inch

Tongs, blacksmith's, pair —

}-inch

1-inch

IJ-inch

181768—21 44

688

J. Tinner's tools and supplies:

Acid, muriatic, pint 1

Sheet zinc, ounce 8

Blow torch

Iron, soldering, with handle, pounds

Mallet trimmers

Sal ammoniac, lump, pounds

Snipe, tinners' —

Large, pair

Small, pair .^

Solder, soft, pounds

Zinc, alloy, lor brazing, pounds, ^

K. Miscellaneous tools and accessories:

Buckets, water As required.

C5ans As required.

Emery wheel, hand

Extinguisher, fire 1 for each box car and moun

Machine spike, steel, 11-inch

Needles, sail

Palms, sewing, leather

Wrench, Stillson pipe, 14-inch

L. Miscellaneous material for repair:
BoHs and nuts, assorted.
Round iron —

}-inch by 5-foot pieces 2

}-inch by 5-foot pieces 2

1-inch by 5-foot pieces 2

Nails, assorted, pounds 30

Fins, cotter, assorted iW

Rivets —

J by 1 inch 50

J by 11 inch 50

1 by 2 inch 50

t by 21 inch... 50

Screws —

Machine, assorted.
Wood, assorted.
Steel angles, bar, plates, etc., should be carried in small quantities and as
required.
M. Fire-control equipment:

Protntctors in decigrades 2

Protractors in mils 1

Scale 1/20000 2

Scale 1/50000 2

Scale 1/80000 2

Double decimet«fr scale 2

Case ol diawing instruments 2

Drawing boards i 2

Pocket compass 2

Battery telescope and tripod 1

Siege telescope with tripod 1

Surveyor's chain with markers 20 meters 1

Steel tape 10 meters with markers 1

Logarithmic tables in degrees and gradt< 2

689

M. Fire-control equipment — Continued.

Drawing board 28 by 28 inches 2

Alidade with level 1

Alidade with telescope 1

Straightedge ruler 2

Triangles 60 degrees 2

Triangles 45 degrees 2

Large board (28 by 28 inches) squared 1

Zinc sheets, squared 1

Drawing pencils, No. 3 ,25

Erasers, rubber 6

Paper, drawing, rolls : 6

Tracing paper, rolls 6

Red ink, bottles 3

India ink, bottles 3

Theodolite 1

Barometer, aneroid, metric 1

Compass declinator 1

Thermometer (Centigrade) 2

Field glasses, prismatic, type £. £., Signal Corps 2

Slide rule or onmimeter 2

Sighting rod 1

Wooden stakes 6

SECTION 9.
SUMMARY OF RECOMMENDATIONS.

659. The foUowing is a summary of the recommendations made in
the previous pages in regard to railway artillery for the United States
Army:

660. Guns. — It is recommended:

A. That the Railway Artillery Program include the following
guns:

i2-hich, 25-caliber howitzer.
16-inch, 25-caliber howitzer.
10-inch, 50-caliber gun.
14-inch, 50-caliber gun.

661. Mounts. — It is recommended:

A. That the 12-inch howitzer be mounted either on the same
carriage recommended for the 10-inch gun below or on a carriage of
characteristics similar to those of the carriage already developed for
the 12-inch, 20-caliber howitzer, plate 194.

B. That the 16-inch howitzer be mounted on a combined sliding,
rolling, and quick emplacing carriage, embodying the sliding recoil
features of the 14- inch model E carriage, the rolling recoil features of
the 16-inch model 1918 carriage, and the quick emplacing features
of the 8-inch carriage (outrigger) and 280-millimeter. German carriage
(pedestal), if practicable, or the base ring of the 14-inch model E
if the German pedestal is impracticable.

C. That the 10-inch, 50-caliber gun be mounted similarly to the
German 280-millimeter, but with modifications, plate 59, to allow
firing from the wheels for limited fire and quick emplacement for
wide-angle fire.

D. That the 14-inch, 50-caliber gun be mounted on the same
carriage recommended for the 16-inch howitzer above.

662. Equipment. — It is recommended:

A. That spare-parts cars be not furnished, and that equipment in
general be supplied in accordance with the recommendations given
in section 8.

663. Shops — Maintexaxce. — It is recommended:

A. That shops in every case be established at the railway artillery
camp to handle maintenance of all such artillery. In the interest of
hasty evacuation with minimum loss, should such evacuation become

(691)

692

necessary, it is recommended that the shop be of the semiportabie
type.

B. That shop equipment be provided in accordance with the
recommendations of section 7.

C. That special attention be given to the obtaining of officers of
long experience and special ability in shop practice for the super-
vision and operation of these shops.

D. That special attention be given to obtaining several officers and
a number of men who are thoroughly familiar with the commercial
railway companies' methods of maintaining standard rolling stock.
Further, that some of these officers and men be retained for peace-
time service. In th,e event that this is not possible, it is recommended
that several C. A. C. officers and a number of men be detailed for a
time to the maintenance service of some railroad company in order
that they may become familiar with the difficulties exp^ienced and
the routine and emergency measures applied.

SECTION 10.

RAILWAY CLEARANCES AND TABLES OF CLASSIHED

INFORMATION.

664. Railway Clearances (41). — In order that the material
contained in this report may be complete from the standpoint of all
who are interested in any phase of railway artillery, it seems wise to
include a discussion on railway clearances. The discussion given in
the following paragraphs is based on a handbook on clearances, pre-
pared in the Railway and Seacoast Carriage Section of the Ordnance
Department, and with which the writer has had some connection.
In the handbook referred to, individual maps and clearance diagrams
are given for each of the roads listed on plate 481. A key map is
given likewise of aU those main lines represented by these roads and
over which the railway artillery would be transported, east, west,
north, and south, and along the coasts and borders, in the event of an
emergency. There are too many individual maps and clearance
diagrams to include in this work and it seems best to omit the key
map, since this volume is for general distribution.

665. Composite Diagram for American Railways. — The com-
posite clearance diagram of railways may be termed an outline or dia-
gram of such shape and dimensions that when the transverse section
of the various railway vehicles remain within its limits, these vehicles
can be transported over all sections of the roads concerned with a
predetermined clearance from obstructions, so long as the distance
between the truck centers of these vehicles is kept within certain
specified limits. Such a composite clearance diagram of railroads
is perhaps an indefinite outline unless full explanation is given as to
what it covers. The diagram shown on plate 481 covers all American
railroads listed thereon. These roads include all coastal lines, Mexican
border lines, some transcontinental lines, and a few central, north,
and south lines.

666. The information from which the clearances were drawn was
obtained direct from the chief engineer's office of each railroad. From
this information a composite diagram was then drawn for individual
railroads. These composites were then compiled into a master com-
posite diagram. The clearance information obtained showed either
actual obstructions or clearance limits with an allowance of 4 inches
between the clearance line and actual obstructions. The composite
clearance diagrams allow 4 inches clearance between actual obstruc-
tions and the outline.

(693)

Ti T 1 t

_________ IP

f «

695

667. The diagram makes no allowance for curves, but it is safe for
(equipment whose truck centers do not exceed 40 feet. On railway
mounts whose trucks centers exceed this dimension, aUowance must
be made for the overhang of the mount in rounding curves. It is
safe to figure a maximum curve of 17 degrees, 337 feet radius, on the
main lines of railroads shown. Hence, the width of the mount wiL
be reduced at least as much as the computed off-set on a 17-degree
curve. A full discussion of railroad curves will be given later.

668. It was early recognized that to compile a clearance diagram
of every railroad system in the country would be an endless and
indeterminate task as well as being worthless when completed. The
futility of attempting to establish such an absolute clearance dia-
gram of every road is best illustrated by the following facts: There
are over 250,000 miles of railroads in America. Some of these roads
are inaccessible to any but the lightest railway equipment and are
located in the interior mountainous regions. For instance, some
standard gauge railroads are used only by the lumber interests.
Special logging cars and locomotives comprise the rolling stock of
these roads. Obviously no piece of railway artillery could ever be
transported over such tracks. Such roads would therefore be useless
for railway artillery shipments and have not been considered.

669. Other railroads, while using standard equipment, touch only
the small central and western interior towns. These roads are gener-
ally branches of the larger systems and it is improbable that any
emergency could ever arise for their use. If it did, the branches would
have to be rebuilt. These roads are not considered on the diagram.

670. To compile a maximum clearance diagram of all the big rail-
road systems of the country would result in such limitation of dimen-
sions of the railway mount that one could not use it for the design of
the heavier caliber guns. The branch lines of some of these systems
present limitations that sometimes interfere with their standard equip-
ment, but the territory covered is so important that lighter rolling
stock is used. Hence it would be unwise to limit the diagram by in-
cluding all branch lines of the big systems. Some of the branch
lines, however, are of vital importance and these have been included .
If it is not possible to reach an important point from one line on
account of some limiting feature, it has generally been found possible
to detour to that point.

671. It must not be presumed from this discussion that railway
clearances can be compiled into a fixed outline or diagram. The
more progressive railroad companies are constantly changing their
clearances and improving their curves. So to keep up to date, it is
necessary to keep in touch with the railroad engineers. These
changes should be checked up every six months and the diagrams
changed if afi'ected.

696

672. Method of Using American Composite Diagram. — The
master composite clearance diagram shown on plate 481 is complete
for all the railroads listed thereon. As previously stated, the clear-
ance outline shown is 4 inches within the actual obstruction line. In
using this diagram the matter given later under the headings of
* 'Railroad curves," ''Offset of middle ordinate/' and ''Elevation of
outer rail on curves" must be carefully considered. In other words,
the outline of the railway mount or equipment considered must not
only come within the diagram, but if the truck centers are greater
than 40 feet, allowance must be made for the three items just men-
tioned. The method of computing these allowances is given under
the proper heading, and these dimensions must be deducted from
the clearance outline shown on this American clearance diagram.
All of this is true only in the event that the truck center distance of
the equipment is greater than 30 feet. It is impossible to state abso-
lutely the degree of curvature of all lines covered by this diagram.
It is a safe assumption to state that the maximum curve over any
road on which railway mounts are liable to be nm is approximately
1 7 degrees. The radius of this curve is 337 feet.

673. The middle ordinate or overhang at the center of equipment
whose truck centers are 30 feet on the 17-degree curve is 4 inches, as
determined by the formula given under paragraph 682 on middle or-
dinate of curves. It is readily seen that this offset enters into the
calculations in determining the extreme width of the railway mount.

674. The elevation of the outer rail on curves does not present
such limitation to the width of railway artillery as might be supposed,
for the reason that the extreme width of railway artillery mounts at
or near the maximum height is generally less than the clearance
diagram. Since the elevation of the outer rail affects the width a
perceptible amount only at its extreme height, it is evident that there
is ample room between the outlines of the mount and the upper
portion of the clearance diagram. The contour of the railway mount
will, however, determine this feature.

675. On such equipment as the ammunition cars this elevation of
the outer rail is of extreme importance, since the car has its extreme
width at the height of the eaves of the roof.

676. Composite Diagrams A and B. — For readv reference in look-
ing up limiting features of the American composite clearance dia-
gram, diagrams A and B are given as covered on plates 503 and 504,
respectively. The limiting features and the railroads on which these
occur are shown on these diagrams together with actual dimensions
above the rail. The two diagrams are, of course, covered by the
master clearance diagram, and are only included for the detailed
information which they contain. These two diagrams are to be

697

used in the same manner as the master composite dia^am and the
full line on each one indicates 4 inches actual clearance inside of the
obstruction line.

677. French Railway Diagrams. — ^As the Ordnance Department
was shipping railway mounts to France, it was vitally interested in
the clearances of railroads in that country. Accordingly, information
was secured which enabled the section to draw the French composite
clearance diagram. This was placed on the same tracing as the
American composite, for it was of vital interest. It is practically
the same diagram as was being used by the officer of the Director
General of Military Railways in designing railway equipment for use
in France. This diagram was, based on proceedings of the Interna-
tional Conference at Berne in the year 1913. No map was prepared
for this European clearance diagram.

678. The railroads in France do not report exactly the same clear,
ances as shown on the Berne conference diagram. It was, therefore,
decided to split the European composite diagram in two (pi. 484).
That part of the diagram on the left of the center line represents the
*'Passe-Partout'' or Berne conference clearance diagram, and the
part on the right of the center line represents a composite of nine
French railroads. A table of clearance for European railways is
given on plate 486.

679. Curves — Middle Ordinate. — ^All of the American diagrams
were worked out on the basis of having 4 inches between the clearance
line and the actual obstruction. On straight-line tracks and on
curves of large radii, this is sufficient for mounts whose truck centers
do not exceed 40 feet. When the truck centers exceed this distance
additional side clearance is necessary. The two components of the
element of side clearance in rounding curves are the overhang of the
mount and the elevation of the outer rail. Before taking up these
two features, it may be profitable to fix in one's mind the meaning
of the accepted manner of expressing the amount of curvature of a
railroad track. Curves on a railroad are usually expressed in degrees
and minutes. This degree in this country means the central angle
subtended by a chord 100 feet long. Approximately 1 degree of
curvature is equivalent to a radius of 5,730 feet. Thus:

5,730X2X3. 1416 = 360X 100

36,001.7 = 36,000

•

Hence, to obtain the radius of a curve in feet, divide 5,730 by the
number of degrees of curvature.

680. In the metric system, instead of the chord being 100 feet,
it is 20 meters or 65.61 feet. So with the central angle remaining
the same, the radius will necessarily be less. This can be represented

698

by 65.61/100 for a 1 degree curve, or approximately f English
measurement. Thus —

10 degree curves = - ,q- =573 feet radius, American, fig. 1.

10 degree curves = .q.. X -^ =375.9 feet radius, French, figure 2,
plate 487.

681. The middle ordinate distance must be subtracted from the
width when it is sufficiently large to come within clearance limits.
In other words, the diagrams allow clearance only for equipment
having truck centers less than 30 feet, and when this is exceeded, the
width of the mount must be decreased by the number of inches of
overhang.

682. Overhang. — The overhang at the center of a car will be the
same as the middle ordinate of the chord whose length is the distance
between truck centers, figure 3, plate 487. This distance may be
obtained by laying out the truck centers on a curve of given radius
or from the approximate formula —

d= ooused, where

i? = radius to center of track
c = truck center distance
d = middle ordinate.

In the event that the mount is equipped with span bolsters an
additional (d) will have to be figured, fig. 4, plate 487. Thus —

^ -SR

683. Super-Elevation. — The super-elevation of the outer rail
on curves will, of course, decrease the clearance. The amount of
this super-elevation is a function of the train speed and the degree
of curvature. An empirical formula for finding the elevation which
gives results sufliciently close is —

/;=.0006S5S2/>, where

E= Elevation of outer rail in inches.
S = Speed in miles per hour.
Z> = Degrees of curvature.

Example for 10 degree curve,

7!;=.000685X30=X10
^=6.165 inches.

'^'f'aken from American I^)C()motive (\).'s Handbook.)

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684. Speead op Rails. — In 1910, the A. R. M. M. Association
recommended the widening of the gauge of track at curves as follows:

Gurvee 8 degrees and leas should be standard gauge. Gauge should be widened
i inch for each 2 degrees or fraction thereof over 8 degrees, to a maTimum of 4 feet 9}
inches for tracks of standard gauge. Gauge, including widening due to wear, should
never exceed 4 feet 9} inches.

685. Weight. — The weight of the railway mount is just as
important as clearance in determining where and how it may be trans-
ported. Each type of mount, of course, weighs diflFerently, and no
attempt has been made in this clearance data to state what weights
can be handled over the lines shown.

686. Inquiries were instituted as to what loads American railroads
could handle when the- clearance data was being obtained. The
majority of railroads reported that th«y could handle loads of
180,000 pounds safely. On weights above this amount, most of the
answers were either negative or ambiguous. The railroads, therefore,
indicate that no general statement will be made as to what load they
can handle. It was necessary to take up each type of mount with
the roads in question giving full information as to wheel loads,
wheel bases, total length of equipment with an outline or silhouette
of the mount. The route contemplated was also given. Only by this
procedure can a definite statement be secured from the railroads.

687. The axle loads for all railway mounts for use in France were
fixed under the direction of Gen. Pershing. This was a limit of 17
metric tons per axle or approximately 37,500 pounds. The M. C. B.
Association standard capacity for an axle with 6 by 11-inch joimials is
50,000 pounds. So the wheel loads on all railway mounts were
comparatively low. This decision required the extremely heavy
moimts to have many wheels. The 12-inch, 50-caliber American gun
sliding railway mount has 32 wheels. The 10-inch French Schneider
sliding railway mount has two trucks of 12 wheels each. From the
foregoing, it will be noted that while the total weight of some of the
•mounts (the American 12-inch gim sliding mount weighs 600,000
pounds), is exceedingly high, the loads per wheel are low.

688. Those dimensions with which the Service would be concerned
in routing railway artillery over the United States are given with the
various existing railway mounts on the following data and profile
sheets. In each case the transverse section given within the United
States composite clearance diagram is ^ composite of the obstructions
throughout the length of the car that figure in the clearance. In the
event that the clearance of any particular mount over certain roads
is foimd so close as to be doubtful, it will be best to look up the draw-
ings of that particular mount in the handbook to determine just where
the limiting features on the moimt are located.

689. Tables of Classified Information. — It was mentioned in
the preface that at the request of the French and- British Technical

706

Services, sections 3 and 10 were being divided and all descriptions
and tabular data on French, British, and Italian mounts would be
given in a second volume which would be available for official use
only. The result is that less than one-third of the descriptive matter of
section 3 and the tabular data of section 10 can be given in this
voliune. The American moimts on which data is given herein repre-
sent the highest points in the development of railway artillery so that
an accurate conception of its present status can be gained. All of
the data on the German mounts has been gained from study of
captured handbooks and examination of the mounts themselves.

707

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APPENDIX I.
THE GERMAN LONG RANGE GUN (43).

FIRST DArS BOMBARDMENT— FIRST IMPRESSIONS.

690. At 7.15 on the morning of March 23, 1918, just two days
after the Germans opened their offensive against the British Fifth'
Army before Amiens, the people of Paris were startled by an explo-
sion of something that had fallen on the Quai de Seine. The explo-
sion was of such magnitude that it could be heard over practically
the whole of Paris. Fifteen minutes later there occurred another
explosion of the same magnitude, but this time closer to the Seine
on the Rue CJharles V; 15 minutes later another explosion occurred
on the Boulevard de Strasbourg near the Gare de TEst. Until that
time Paris had never been bombarded except from airplanes and
Zeppelins, and the first thought of the people was that they were
being bombarded from some new type of aircraft that was being
operated at such a height that it was practically invisible.

691. The explosions continued to occur throughout the morning
at very uniform intervals of 15 minute^, and by evening 21 explo-
sions had occurred at the places shown on plate 509. These are men-
tioned by their exact location under March 23 in the table given
as plate 510. After the first few explosions between 7 and 8 o'clock
in the morning, business in Paris practically ceased. Stores were
closed and part of the Metro system ceased to operate; ticket offices
in some of the railway stations were closed, and great numbers of
people could be seen walking the streets looking skyward trying to
locate the planes that were dropping the supposed bombs.

692. Information of the extraordinary bombardment was tele-
phoned and telegraphed over practically the whole of France within
a few hours and was received everywhere in amazement. After a
few hours on the first day a sufficient number of the fragments of
the exploding agent were collected by officials in Paris to identify
it as a projectile being fired from a gun, rather than a bomb being
dropped from an airplane. By noon representatives of the Heavy
Artillery Section of the Ordnance Department, located at Tours,
had made preliminary calculations in response to telephone instruc-
tions from Paris, giving the probable muzzle velocity at which a

(723)

724

projectile would have to start in order that it might travel from a
few kilometers within a point of the German lines nearest Paris to
the center of Paris. Inquiries were made likewise of the section as
to the possibility that these projectiles could actually be coming
from a gun within the German lines. The reply was that the probable
muzzle velocity of the projectile, if it was actually being fired within
the German lines, was not less than 4,500 feet per second. No such
muzzle velocity had, to their knowledge, ever been realized, but with
a gun of sufficient length and with a powder burning at a satisfac-
torily low speed, it was considered quite possible that the projectiles
were being fired from within the German lines. By the end of the
first day, officers of the French as well as the American Armies were
quite certain that the projectiles were being fired from a newly
designed long range gun, located within the German lines, and
operating at a probable range of 110 kilometers (68.8 miles).

693. During the next few days some interesting theories were
advanced in the various newspapers. In one case it was maintained
that the projectiles which arrived in Paris were being fired from
another much larger projectile, which actually served as a gun.
This larger projectile was said to have been fired from a gun within
the German lines and upon attaining a certain height, a charge of
powder within the larger projectile was automatically ignited, firing
the smaller one to a much greater distance. The theory that the pro-
jectiles were being fired from guns concealed in abandoned quarries
or in heavily wooded regions near Paris received considerable credence
and diligent search was made of all such places to be certain that it
was not true. A third theory was that the projectiles were being
fired from a pneumatic gun located within Paris.

694. A plotting of all the bursts for the first day showed results
that were very puzzling. If the guns were being operated at com-
paratively short distances, the only way to account for the tremen-
dous dispersion was on a basis of actual laying of the gun for diflFer-
ent objectives. This theory did not seem plausible, however, because
if the gun was actually laid on given objectives, these objectives were
of relatively small importance. If, on the other hand, the projec-
tiles were being fired from a gun at a great distance, it was seen at
once that the dispersion was so great as to make it practically impos-
sible to hit with any certainty any objective much smaller than that
portion of Paris within the walls. It was noticed that the disper-
sion in direction, that is, to the right or left of the theoretical line
on which the projectiles were arriving, was comparatively small,
while the dispersion in range, that is, over or under the probable
point at which the projectiles were supposed to arrive, was very
great. Examination of the map, plate 488, shows that on this

725

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726

fiiBt day, when the gun was new, the average dispersion in range
was very small compared with the dispersion on later days when the
gun became worn.

695. Evidence received later indicates that at the end of this first
day's bombardment the first gun was about half worn out. Eighteen
projectiles had fallen within the walls of Paris and 3 outside; 15
people had been killed and 36 had been wounded. The destruction
of property had been comparatively smaLi. By '* comparatively" it
is meant that the destruction was small in comparison with that
wrought by the 100 and 300 kilogram airplane bombs. Whenever the
projectiles landed in the street or in an open plot of groimd, the hole
made was seldom more than from 12 to 15 feet in diameter and from
4 to 6 feet in depth. When the projectiles struck buildings it was not
unusual to have them explode in the interior without showing any
considerable signs of damage on the outside.

696. On the 24th of March 13 projectiles fell within the walls of
Paris and 9 without, killing 11 people and wounding 34. On the 25th
4 projectiles fell within the city and 2 without. This was the end of
the first gun. It was worn out, and no more firing was done until the
29th, when the second gun began its work.

697. Search of the files of the French War Office revealed the fact
that fidl drawings and plans had been on hand for quite a long time
for just such a gun as the Germans were probably using. These speci-
fications had been submitted several years before and had been dis-
carded because of the excessive expense and the tremendous difficul-
ties involved in manufacturing such a gun. It was considered like-
wise by those who had turned down the specifications that the value
of such a gun was extremely questionable. It was realized that its
dispersion would be excessive and that with the powders with which
the service was then familiar it would be exceedingly difficult to
secure a muzzle velocity sufficiently imiform to do effective work.

DETAILS OF THE BOMBARDMENT.

698. When the bombardment was over, an examination of the period
over which it had extended indicated that it had been divided into
three distinct series. The first extended from March 23 to May 1, the
second from May 27 to June 1 1 , and the third from July 1 5 to August 9.
It seems certain that this division into series was a part of the plan
of the large offensives being waged during that time. The table,
pages 751 and 752, gives the bombardment by days during this entire
period and shows the number of projectiles falling within and without
the waUs of Paris each day, the number of people killed and wounded,
and the exact places where the projectiles fell. During the first few
days of the bombardment the firat projectiles arrived between 7 and 8

727

o'clock in the moniing and continued to fall at intervals of 15 minutes
through a portion of the day. On later days the bombardment would
begin at 12.40 noon.

699. Much has been said with reference to the effect of this bom-
bardment on the people of the city of Paris. The writer's first direct
acquaintance with the bombardment was during the third and fifth
days. With considerable surprise it was observed that already the
people were taking it quite philosophically; in fact it could not be seen
that they were paying much attention to it at all. At intervals of
about 15 minutes muffled explosions would be heard in different parts
of the city, seldom two consecutive explosions in the same vicinity.
Many people would stop for an instant and attempt to decide from
what direction the sound had come, after which they would go on their
way apparently unconcerned. It was, of course, still sufficiently
novel to be of considerable interest, and people were talking about it
everywhere. It is quite probable that the regularity with which the
projectiles were arriving got on the nerves of some people, and that the
bombardment was responsible for the departure of some of the people
who were crowding the trains west and south from Paris. It seems
more certain, however, that by the 1st of June the close proximity of
the Germans to the city of Paris, together with the anxiety caused by
another drive impending, added to the effect of the heavy bombard-
ments from airplanes on every clear night, had far more effect than
the gim. The visible destruction of property was so slight as to
give little evidence to anybody traveUng about the city that the
explosions they were hearing from time to time amounted to any-
thing. The newspapers were very careful to avoid any discussion
or even a lengthy reference to the bombardment from day to day,
and neither gave the locations of the places where the projectiles had
fallen nor the number of kiUed Or wounded.

700. The Germans must certainly have known that their gun was
not a profitable investment for the destruction of property; hence
they must have continued the bombardment purely for its destruc-
tive effect on the morale of the Parisians and its beneficial effect on
the morale of the Germans. This is likely the purpose which
prompted the construction of the guns. In his book, ^*My Thoughts
and Actions,'' Gen. Ludendorf says: ''During the battle we had
commenced bombarding Paris from near Laon with a gun having a
range of 75 miles. This gun was a marvelous product of technical
skiU and science, a masterpiece of the firm of Ejrupp and its director,
Rausenberger. The bombardment made a great impression on
Paris and on all France. Part of the population left the capital,
and so increased the alarm caused by our successes." He is right;
the bombardment did make a great impression; it made everyone
more angry and alarmed very few. It is certain now that they

728

could ill afford to use their manufacturing facilities for the making
of such guns as these at a time when they were so desperately in need
of heavy field guns to assist their armies in their big drives.

701. Long-range or super guns received consideration from the
Allies for a very short period. There was a tendency for a few
weeks to favor the construction of a great number of them, but a
saner view sooh prevailed, and actual steps were taken for the con-
struction of only a very few. Both the British and the French
Governments began the construction of a few, some of which have
now been finished. They built them, however, with a clear under-
standing that they could hope for but little more from them than
the Germans were getting from their own. American Ordnance
officers feel that it would not profit us to construct more than two
or three such guns at most and probably none at all.

702. Within a very few days from the beginning of the bombard-
ment it was possible through careful examination of the direction
of the passage of the projectiles through various buildings, to deter-
mine quite accurately the direction of their arriral and the probable
place from which they were coming. This place was in the Forest
of Gobain, west of Laon. Very soon thereafter the French Air Serv-
ice was able to locate in this same forest three positions, from any
one of which, or possibly from all of which, the guns were being
operated. Only one of these were sufficiently close to the German
and allied lines to permit of any possibility of operating against it
with the heavy guns then in service. The gun selected was a 3*4
centimeter (1.3.38 inches), 45-caliber French gun on a railway mount.
This mount was run up to a point very close to the lines and behind
a hill of such size as to effectively conceal it from German line ob-
servers. It was well camouflaged by nets against the air observer
tmd against German sound ranging ajSparatus by placing two smaller
guns at the right and left and several hundred yards behind it. These
smaller guns were fired at intervals of one and two seconds before the
larger gun, and evidently had the effect of so disturbing the German
sound ranging apparatus as to make it impossible to locate the heavy
gun. After a half day*s firing from the 34-centimeter gun, air photo-
graphs indicated that the emplacement had been destroyed. The
airmen undertook to demolish the other two emplacements and their
photographs indicated that they had inflicted considerable damage.
Apparently they did not secure any direct hits for the gun or guns
continued to fire without any long intervals.

703. After the advance of the Allies it was impossible to determine
from examination of the emplacement which had been nearest the
allied lines whether a gun had actuaUy been on this position or not.
A German artillery officer who worked with the Americans for some-
time in the forward area after the armistice and who spoke with such

729

certain knowledge of the long range gun as to indicate that he knew
the details of design and had seen it, insisted that the position that
had been destroyed by the Allies had not had any gun on it.

704. Mention has already been made of the destruction of property
by these long range projectiles. Except in a few places where the
damage was so exposed as to attract attention, no matter how slight
it might be, there was little evidence that the bombardment had any
effect. On March 29, the day on which the second gun began to fire,
and fired only four projectiles, the one projectile which landed within
the city of Paris struck and knocked out the keystone of one of the
arches in the roof of the Church of St. Gervais near the Hotel de Ville.
The falling of the keystone caused a large part of the arch and the
roof to ooUapse and most unfortunately the church was quite full of
people at the time. Examination of the table below shows that
this day holds the record for casualties. On one other occasion a
projectile burst in the lobby of a hotel, killing a number of people,
but doing comparatively little material damage. Some idea of the
damage ordinarily wrought can be gained from examination of plate
489. This shows the hole made by the explosion of one of the shells
in the Garden of the Tuilleries. It will be noted that the wall is not
damaged and that only a comparatively small hole has been made
in the ground.

The bombardment of Paris by the Gemian long-range gun^ Mar. 23 to Aug. P, 1918.

■

Number of projectiles.

Killed.

15
11

1

188

10

1
8

Dates.

Within
the walls.

Outside
the walls.

Wounded.

Mar. 23

18

13

4

1 1

18

3

3

3

1

2

3
9
2
3
3

36

24

34

25

3

29

68

30

60

31

1

Apr. 1

1
1

8

^ 2 :...:::..:..:.... :.

3

3

6

4
1

1
2
2

1
2
1
2

3

7

11

12

13 «

5
5
6
3
3
2
1
2

9
2

21
14

14

15 5

16

19

17

114

21

24 ^

1
4

25

ft

1

1

26'

30

3
1
7
4
5
5
3
4

Mav 1

5

27 »

2K

7
6
5
4
1

4

1

1

13

20
2

29

7

30

5

31

June 1

'

» Shell struck an arch in the roof of the Church of St. Gervais.

Night and day.

Night.

SHELL HOLE IN THE GARDEN OF THE TUILLERIEI

731

The bombardment of Pane by the German Umg-range giifif Mar, tS to Aug, 9, 1918 — Con,

Number of projectiles.

Killed.

Dates.

Within
the walls.

Outside
the walls.

Wounded.

June 3

6

2

4
1
3
1
3

8

4

4

3

1

1.

2

16

7

1
2
3
2
1
1

4

8

0

0

10

13

11

July 15

0
4

13
12

8
1
2

6
3
32
8
7
1
3

0

16

8

AuE. 5

4
7
4
4
10

61

6:::;:::::;:::..:::..:....:.:.:..::: :::.:.:::...

30

7

43

8

9

6

Total

1S3

120

256

620

705. Even diiring the active periods of the three series noted
above there were many days on which the gtin did not fire. It is
quite certain that between the 25th and 29th of March the first gun
was being removed and a new one placed on the carriage. By the
end of the 25th of March 49 projectiles had arrived, and the probable
life of the guns is not more than 50 roimds. It is likely that the
guns were changed again between the 7th and 11th of April and
between the 21st and 24th of April.

706. After the armistice it was learned that the Germans had
constructed a total of seven gims. These guns were first constructed
to a diameter of 21 centimeters (8.27 inches) and after being worn
out as 21-centimeter guns were being rebored to 24 centimeters
(9.45 inches). All of the projectiles of the first two series were 21
centimeters in diameter, but during the last days of the third series
the projectiles were 24 centimeters in diameter, indicating that the
entire seven guns had been worn out, and that probably the gun
that had commenced firing on Paris on March 23 as a 21-centimeter
gun had been rebored and was fired again as a 24-centimeter gun.
It was learned also that the Germans were reboring the remainder
of the seven guns and were constructing additional gims at E»3en.
Representatives of the Ordnance Department found in the Skoda
Works at Pilsen three more gims which the engineer at these works
said were under construction as long-range gims at the time of the
armistice. In July, 1918, the Intelligence Service transmitted
information to the effect that one gun had been destroyed by a
premature explosion. No confirmation of this report has ever been
found and it can not be considered a certainty.

707. The third series began on July 15 with 10 projectiles, followed by
4 projectiles on the 16th. The bombardment then ceased for three

732

weeks, beginning again on August 5 and continuing daily until the 9th.
On this day 12 projectiles arrived, only two of which fell within the
walls of Paris. The famous bombardment was finished. A compari-
son of the distribution of the bursts on this last day, plate 490, with
the locations on the first day, plate 488, is very interesting. On the
first day a considerable portion of the projectiles fell within a very
small area in the northeastern section of Paris. On this last day it
vnll be observed that they are scattered over the eastern section of
Paris and no two are very close together. The last projectiles of the
entire bombardment fell between 1 and 2 o'clock on August 9.
Already the Allies in their successful drive north of the Mame and
between Soissons and Rheims were driving the Germans back so
rapidly and had made such progress as to put the long-range guns in
serious danger.

708. Plate 491 shows the location of all of the bursts within the
walls of the city, a total of 183 ; 120 more fell outside the city, making
a total of 303 fired from seven 21-centimeter guns and probably one
gun rebored to 24 centimeters. The bombardment included 44 active
days. Even before the last day of the bombardment American forces
operating north of the Mame had captured an emplacement 9 kilome-
ters (5 miles) north of Chateau-Thierry. This emplacement will be
described in detail later. It was 86 kilometers (53.4 miles) from Paris
and it is understood that it was a new emplacement from which the
Germans had hoped to operate the super guns more effectively.

DESIGN OF THE GUN, CARRIAGE, AND EMPLACEMENT.

709. Introduction. — It has been mentioned before that the
Germans used seven guns of a caliber of 21 centimeters (8.27 inches),
that they had rebored at least one of them to 24 (fentimeters (9.45
inches), and that at the time of the armistice three more guns were
under construction at the Skoda Ordnance Works at Pilsen in Austria,
During the period of active warfare many reports were received with
reference to the design of the gun, but never any information with
reference to the carriage. The various reports on the gun agreed
quite closely in the essential details.

710. In May, 1919, a commission of Ordnance officers was sent to
the Skoda Works in Austria for the purpose of investigating their
methods of constructing large and small ordnance. While there
they secured additional data from the chief engineer of the plant with
reference to the design of the gun, and saw the three guns which had
been in process of construction on November 11, 1918. This chief
engineer stated that when the first German gun began to fire on Paris
it was as much a surprise to the Austrians as it was to the Allies.
Shortly thereafter he went to France to examine the gun and observed

■33

S

o»

H

O

o

09

PQ

H

O

S5
O

<

o

734

00

PC

<

O

3

•J

n

n

00

PS
P
ff

O

%

O

►^

o

735

it in action. It was not until a few months before the armistice
that the three guns were sent to Pilsen for conversion into long-range
guns. Evidently the Germans had considered the bombardment a
success, or sufficiently so to warrant the use of manufacturing facili-
ties for the construction of a greater number of guns than they were
able to handle at the Krupp Works at Essen.

711. The details of the design of the carriage for the gun were not
learned until April, 1919, although it had been quite certain since
August, 1918, that the emplacement found north of Chateau-Thierry
was intended for the carriage of the long range gun. Until July 1 ,
1919, no direct information had been received from the Germans
with reference to the design of any part of the entire mechanism
except the gun on which, as mentioned before, information had been
received at various times before the armistice; the guns themselves
were examined at the Skoda Works at PUsen. Just why the Germans
refused to talk about this gun is not known. In December, January,
and February, 1918 and 1919, a German engineer who was working
with the American forces in the region northeast of Verdun helping
identify long delay fuses and assisting on other technical matters
said that he was acquainted with the design of the gun and had seen
it in operation. Very curiously, however, he refused to give any
information with reference to the details of the design; was quite
positive in his assertions that the Allies would never see any of the
guns, and certainly not any of the carriages. This was difficult to
understand in view of his perfect willingness to talk about the details
of design of any other piece of ordnance that he was at any time
asked about, and it was more curious in view of the fact that there
is really nothing wonderful about the design of the long-range gun,
its carriage, or its emplacement.

712. Gun. — ^All of the long-range guns were constructed from
worn-out 38-centimeter (15-inch), 45-caliber guns (17.1 meters or 56
feet in length). The converted gun was in two parts, the main sec-
tion 30 meters (98.5 feet) in length and the forward section 6 meters
(19.7 feet) in length. The 38-centimeter gim was bored out and a
very heavy tube with inside diameter of 21 centimeters was inserted;
12.9 meters (42.3 feet) projected beyond the end of the original
gun and over this projecting portion another hoop was shrunk and
locked to the forward hoop of the old gun. This 21-centimeter
tube was rifled at a uniform twist throughout its length. The other
section, 6 meters in length, was attached by means of an interrupted
thread and heavy outside collars or flanges. This section was unri-
fled and was of an inside diameter equal to 21 centimeters plus twice
the depth of the grooves in the rifled section. It was assembled to
the gun in the field and not removed until the gun had been worn
out. The total weight of the original 38-centimeter gun was 152,550

181768—21 47

t.^xs^^ I

737

pounds and the weight of the reconstructed gun approximately
318,000 pounds. The 21-centuneter liner was of such thickness that
on beiag worn out at this caliber it could be rebored first to 24 cen-
timeters (9.45 inches) and later to 26 centimeters (10.024 inches).
Its probable life at any one caliber was not more than 50 rounds and
the maximum powder pressure did not exceed 3,000 atmospheres or
4^,000 potmds per square inch. The design of the breech mechanism
of the original 38-centimeter gun did not require modification.

713. The long-range guns constructed by the British and French
Governments do not follow the German design to the extent of
having a smooth-bore section on the front. The purpose of this
feature was for some time in doubt and is worthy of some discussion.

714. The gun just described is approximately 3 meters longer
than either the British or French long-range guns, both of which
are rifled throughout their length. Two reasons might be given for
the extra section.

715. Possibly additional linear velocity was imparted to the pro-
jectile as it traveled through the 6-meter smoothbore section. It
seems improbable, however, that this could be its primary purpose ^
inasmuch as the muzzle velocity was such a variable quantity. It
is more probable that its purpose was to align the axis of the pro-
jectile more perfectly with the axis of the bore of the gun and reduce
to a minimum the angular velocity of yaw as the projectile left the
muzzle. When it is understood that this projectile was to mount
to a height of about 24 miles and travel a horizontal distance of
76 miles, it can easily be appreciated that any tendency that the
projectile might have to throw its axis out of alignment with its
theoretical path would have disastrous results. Through the imprac-
ticability of making projectiles fit perfectly in a gun, they have a
tendency to hammer the walls as they travel down the bore. This
hammering action of the projectile is the result of the operation of
two forces, the one tending to increase its linear velocity and the
other to increase its rotational velocity. The latter force is acting
only while it is traveling through the rifled section. It is invariably
true that just as the projectile is leaving the ordinary gxm it is on
one of its up, down, or crosswise hanmi^r strokes, and that the axis
has a tendency to yaw or deviate from its theoretical path at a
certain angular velocity. Cardboard screens placed in front of guns
in proof firing invariably show elongated holes, and not infrequently
very decidedly So, even at no greater distances than a hundred feet
from the muzzle. This tendency to yaw has a detrimental effect
on the accuracy of even our comparatively short-range guns, but
no effective means have yet been devised to neutralize it. With the
extreme range gun it is so much more serious that it seems quite
likely that the Germans adopted this method of neutralizing it,

738

thereby reducing the dispersion both in range and in direction. It
is not improbable that the German gun was first constructed with-
out the smoothbore section and that its shooting was found to be
so erratic as to require the addition of this feature.

716. This gun was operated at a muzzle velocity of from 1,500
meters (4,920 feet) to 1,600 meters (5,248 feet) per second and at an
elevation of 55 degrees. This 55 degrees is worttiy of* comment
inasmuch as it has ordinarily been supposed that nothing coidd be
gained in range by elevating a gun above 45 degrees. It is known,
of course, that if a projectile-is fired in a vacuum its maximum range
is attained when it starts at an elevation of 45 degrees. When fired
in the air, however, the initial angle which permits it to attain its
maximum range depends both on the caliber and weight of the
projectile, and the velocity at which it leaves the gun. With rea-
sonably large and well-designed projectiles it may be said that for
each muzzle velocity (A) there is a density of air (ft) into which the
projectile should enter at an approximate angle of 45 degrees. For
this projectile and the muzzle velocity of 1,500 meters per second the
initial angle is 55 degrees. It is very doubtful whether any addi-
tional range can be secured with any projectile at any muzzle velocity
at an angle above 55 degrees.

717. Attention was called in the discussion of the first dav's
bombardment to the tremendous dispersion in range. Some of the
projectiles fell just within the wall at the northeast side of Paris, and
some within the walls at the southwest side. This is accounted for
by the fact just mentioned, that the muzzle velocity of the projectile
varied as much as 100 meters per second. It was impossible with
the powder that the Germans were using to secure a muzzle velocity
with a variation of less than 100 meters per second.

718. Cradle. — The cradle is a cylinder of simple design having
ribs at long intervals and of a depth of only about 3 centimeters,
plate 410. The walls of the cylinder have a minimum thickness of
10 centimeters and a maximum thickness of 13 centimeters over the
ribs. The diameter of the main trunnion is 46 centimeters, and the
length 33.5 centimeters. A collapsible counterweight is attached
to the top of the cradle. In firing, the two sections of this counter-
weight are raised and locked together for the purpose of raising the
center of gravity to such an extent that the gun may be elevated
and depressed more easily. This cradle is of a naval design, the front
section being so shaped as to close the opening in a turret. It is not
improbable that the cradle as well as most of the 38-centimeter guns
were removed from German ships or coast fortifications.

719. Recoil Mechanism. ^ — The recoil mechanism is composed of
two hydraulic recoil cylinders and one spring-pneumatic recuperator
cylinder, all attached to the bottom of the cradle, plate 403. Each of

739

the recoil cylinders is a separate cylinder carried in brackets cast on
the cradle, and each is provided with a buffer approximately 32
centimeters long. The plugs through which the cylinders are filled
are on the ends of the buffers. The approximate length of recoil is
1.3 meters (50.5 inches). This distance is of course approximate and
was arrived at after careful examination of the cradle. A report
examined in the office of the Chief of Artillery of the Belgian Army at
Brussels gives the length of recoil as 1.16 meters. Inquiry disclosed
the fact that this length of recoil was approximate also.

720. Two rods screwed to the recoil lug of the gun, plates 403 and
405, and extending to the rear, carry a heavy crosshead to which the
piston of the recuperator cylinder is attached. The recuperator
cylinder is likewise a separate cylinder carried in brackets cast on the
cradle. At the rear on both sides it is planed to serve as a guide
for the recoil lug to prevent rotation of the gun.

721. Elevating Mechanism.— The elevating mechanism of this
mount is extremely heavy and unique in design. The cradle was
evidently originally provided with the screw type of elevating
mechanism, the screw being hinged to the cradle at the rear end.

722. The specification that the gun be provided with an elevation
of 55 degrees necessarily led to the discarding of the screw mecha-
nism. The straight racks shown on plates 400, 407, 408, 409 shde
in ways which are parallel to the inclined forward ends of lower chords
of the side girders. It was necessary to put them in this position to
secure sufficient movement to attain 55 degrees. At the lower end
they are connected with each other by a heavy shaft to which are at-
tached the two connecting rods running up to the bottom of the
cradle, plate 409. Provision is made for two handles on each side of
the car, each for two men, plate 409, and a two-speed transmission
is provided, permitting the mechanism to be operated at low or high
speed. The ratio of the gearing at low speed is 4 J turns of the handle
for 1 degree of movement of the gun. It was not possible to deter-
mine the ratio of high speed since the two men making the exam-
ination could not operate it. It seems probable, however, that
eight men could operate the mechanism at high speed without undue
difficulty.

723. Traversing Mechanism. — (See ^'Ajichorage.")

724. Railway Car Body.— ^The railway car body shown on plates
400, 413, 415, 416 is made up of two single-web side girders connected
at the front and rear by heavy structural steel transoms. They are
further reenforced in the front by the heavy cast-steel housing for the
elevating gear. The trunnion seats are of cast steel and are simply
bolted to the top chord with single-key plates at their rear. This
single-key plate has the positive backing of one top-cover plate. The
face of the horizontal section of the lower chord of the side girders is
planed and is provided w4th key plates at each end, plate 416. Eight

740

2-inch holes are provided in each lower chord at the front end and six
at the rear for bolting the mount to the emplacement.

725. Anchorage. — ^When the German army had retired from the
safient between Soissons and Rheims in August, 1918, the emplace-
ment shown on plates 417 and 418 was found in the Bois du Chatelet,
9 kilometers directly north of Chateau Thierry. This emplacement
was in process of installation and had not been completely erected.
The Germans attempted to destroy it, but succeeded only in ripping
loose a few plates. At the time the emplacement was captured no
description of any kind was available of the carriage for which it was
intended. The writer's failure to find any emplacement in Belgium
from which the mount examined there could be operated, led to fur-
ther examination of the emplacement in France, and it was found
that they fitted perfectly.

726. The emplacement is in two main sections, one a base and the
other a rotating section. The rotating section, plates 419 and 420,
is about 28 feet 6 inches in diameter and is supported on 112 8-inch
steel balls. The base is about 35 feet in diameter and 6 feet in depth.
On plate 417 there can be seen at right angles to the direction of the
track of the rotating section two girders, on the ends of which are key
plates or pads. The plate which is labeled has six holes in it and the
plate on the opposite end of the girder has eight.

727. The mount is run onto the emplacement with the rotating
section in the position shown in plate 420. It is then raised by the
four jacks which can be seen at the left of plate 417, and are shown
in their exact positions in plate 420. When the mount is raised the
trucks are removed and the rotating section of the emplacement
turned through 90 degrees. On lowering the mount onto the emplace-
ment, the key plates on the bottom chords of the carriage are fitted
to the corresponding key plates on the emplacement. The emplace-
ment is shown in process of installation, with the Gantry vcrane still
in place, plate 421.

728. The carriage on which the gun is so mounted as to be capable
of movement in a vertical plane only, is traversed by rotating the top
section of the emplacement. A complete circular traversing rack
made up of angles and steel pins is bolted to the structural base, plate
422. A pinion carried on a vertical shaft on the side of the rotating
section which corresponds to the rear of the carriage engages with
this rack and the mechanism is driven by two-man handles on a
horizontal shaft carrying a worm engaging with a worm wheel on
the top of the vertical shaft, as shown at the right of the top view,
figure 420. This shaft may likewise be driven by means of the four
handles mounted on the two cases in the center of the rotating section
and connected with the worm wheel and shaft through two shafts

741

carrying two universal joints each. Apparently the mount was
generally traversed by means of these latter handles, if one may
judge of the scheme of operation from plate 422.

729. Camouflage.— In the case of the emplacement found in the
Bois du Chatelet, sockets were placed in the center of the approach
track at intervals of about 30 feet, into which trees with tnmlffl up to
about 6 inches in diameter could be placed for the purpose of conceal-
ing these tracks. The Gantry crane, as well as the emplacement,
while in the process of installation, were covered with tree branches,
plate 421, and raffia nets were stretched over the mount from the
trees on either side, plate 422.

730. Trucks. — ^All of the trucks as well as the span bolsters are
constructed entirely of structural steel, as shown on plate 423. The
front trucks contain five axles each, and the rear trucks foiu* axles
each. The joiunals are approximately 14 centimeters in diamteer by
22 centimeters in length. The wheels are 95 centimeters in diameter.
On the front trucks three wheels are provided with two brake shoes
each; on the rear trucks the end wheels are provided with two shoes
each and the inner wheels with one shoe each. The braking is done
by hand only. The axles are equalized in pairs only. The center
axles of the front trucks have no connection with the others. On
plate 400 a portion of a circular rail can be seen on the top of the front
truck on which the pads attached to the span bolster on each side bear.

731. Ammunftion Supply System. — ^The provisions made for sup-
plying anmiunition are shown on plates 424, 425, and 426. These
same provisions were used for the operation of the 38 centimeter,
45-caliber naval guns from which the long range guns were made.
The extension of the car body shown on plate 426 was used for the
operation of the 38-centimeter gun under certain conditions. This
was not required and was removed when the long-range gun was
operated on the carriage. On plate 425 a removable plate can be
seen between the shot truck rails. Above this removable plate is a
light bridge in the center of which is seen a ball on the end of the
cable used in hoisting projectiles through the hole in the floor. This
cable runs over a series of pulleys to a small drum in the box on the
top of the left side girder. The ammunition was supplied from the
storehouse over the narrow-gauge track shown on plate 424, the
circular portion of the track being under the opening in the center of
the floor of the mount. The gear in the box on the side girder is of
the double speed variety, the high speed being provided probably for
rapid operation in the hoisting of powder.

732. AMMUNmoN. — ^The projectile used with this gun is shown on
plate 493. Its weight is 120 kilograms or 264 pounds. The length
of the main portion of the projectile is 490 millimeters or approxi-

742

PukTB 493

-^^

DESIGN OF THE OERMAN LONQ-RANOE PROJECTILE.

743

matelj 19.3 inches. To this is attached a false ogive or cap, the
exact length of which is not known; it is probably as long, if not
slightly longer than the main portion of the projectile. The radius
of the curve of this ogive is about 7 calibers or 58 inches. It will be
noted that the charge is separated into two parts by a diaphragm
which has a number of holes in it. Two fuses are used, the one in
the diaphragm and the other in the base. All of these projectiles
are most carefully machined to elaborate specifications in order that
the weight and dimensions might be practically exact and the center
of gravity perfectly located; even after they are thus machined
they are sorted out into lots according to their characteristics by
weight, dimensions, and location of the center of gravity and the
various lots of projectiles marked wnth center punch marks. The
necessary corrections in elevation and deflection are calculated for
the projectiles of these various lots. The projectiles which fell in
Paris were successively marked with three center punch marks in a
triangle or four center punch marks in a square, etc.; projectiles of
the same marking arrived consecutively.

733. The outside of the projectile is provided with two copper
bands which served as gas checks and in front of each of these copper
bands the projectile is enlarged and rifled for a length of 70 millimeters
(2.7 inches). The shear from the extreme acceleration necessary to
produce the required muzzle velocity is such that the ordinary
copper bands could not be made to serve as rotating bands. The
shearing strength of copper is not sufficient to stand the strain
that would have been put on the bands with so great an acceleration.
The friction between the lands of the gun and the projectile is so great
as to wear the gim appreciably on each round fired. This was evident
from examination of the copper bands of successive projectiles. As
a result of the necessity for providing rifled projectiles, it is necessary
in placing the projectiles in the bore of the gun to fit the forward rifled
section of the projectile into the beginning of the rifling of the gun,
plate 514. The exact details of the design of the portion of the tube
between the beginning of the rifling and the powder chamber are not
known. It seems quite prpbable, however, that there is a smooth
section of about 12 inches into which the portion of the projectile
back of the first copper band fits, bringing the base of the projectile
to the end of the powder chamber. The fact that the forward rifled
section of the projectile is already fitted into the grooves of the gun
makes it certain that the rifled section at the rear would likewise fit
as the projectile begins to move up the gun.

734. It has been noted before that this projectile departed at a
muzzle velocity of from 1,500 to 1,000 meters per second. The
velocity remaining on its arrival in Paris was approximately 700 meters
per second and the time of flight about three minutes.

744
735. The analyses made of the various parts of the sheU showed

Shell.!

Gap
bolder.t

Gap.

Diar
ptaragm.*

Copper
band.

Dnnkiik
shells.

c

a43-0 86
.27- .49
.24- .81
.04- .10
.01- .06

1.82-2.32
.83-1.45

a68-0.78
.27- .36
.19- .28
.OS- .07
.03- .07

2.10-2.39
.96-1.44

aio-ai8

.41- .97
.08- .05
.05-. 11
.04- .067
.11
.2

aoo

.09
.61
.04
.04

a72

Mn.

.26

Bi

.23

8.:....:::.:.:::::::::;::::::::::::::

03

p

.04

Nl

2.41

Cr

1.33

Pb

0.12

.21

99.67

Fe

CU 4

! Pnuscically a parting.

>Cast.

• Forging.

736. Not a single one of the 303 projectiles that fell in or about
Paris failed to detonate. Evidently the two fuses were responsible
for this excellent record. The practice of separating the charges
into two parts by a diaphragm is not new. The diaphragm had been
used before in French heavy projectiles as a guarantee against the
effects of inertia which might either provoke a premature explosion
in consequence of the friction of the molecules of the charge against
each other or might bring the charge beyond the critical density
point after which it would probably not detonate. At one time a
theory was advanced to the effect that this diaphragm separated two
liquids which mixed and detonated upon the fall of the projectile.
There seems no good reason to believe that this could have beeji so.

737. Previous Designs and Limits in Design. — It has already
been mentioned that investigation disclosed shortly after the begin-
ning of the bombardment that an almost identical design had been
proposed to the French Government not many years before. Further
search of French and English records has brought to light the fact
that the rifled projectile is quite old and seems to antedate the copper
band considerably. In 1892 Sir Alfred Noble made a lOO-caliber
6-inch gun which gave a muzzle velocity of 3,700 feet per second;
in the same year the French Government constructed a 10-centimeter
80-caliber gun from which they attained almost the same muzzle
velocity. It is not known what range was secured in either case.
The forms of most standard projectiles* at that time was not such,
however, as to make it possible to secure the maximum range from
the above noted velocity.

738. In taking up the design of such guns again the French and
English services found that with guns of practicable length and
muzzle velocities attainable with guns of such length, and with
available powders, the projectile that would permit the greater range
to be realized would be approximately 8 inches in diameter and
weigh from 225 to 250 pounds. An appreciable change up or down
in the diameter or the weight of the projectile would result in a loss

745

of range. The gun designed by one of our allies uses a projectile
weighing 240 pounds and a powder charge of 350 pounds. One of
the pieces of powder examined was about 2.5 feet in length and
roughly elliptical in cross section, the axes being about 1 inch and
one-half inch, respectively. It is interesting to note in this case
that the powder charge has a weight about 50 per cent greater than
that of the projectile. If the weight of the charge were increased,
calculations indicate that most of the energy of the gas would be
absorbed in the work of accelerating the charge rather than in
accelerating the projectile and no greater muzzle velocity would be
obtained.

739. One of the vital requirements made of the powder is that it
bums at a rate siifficiently slow to avoid excessive pressures and to
give a uniform pressure through a large portion of the period of the
travel of the projectile in the bore of the gun. The powder made
by one of our allies for their long-range gun is in flat stripe resembling
cardboard. These strips are 3-ply, the various sections burning at
different rates. The large sticks of powder mentioned above for the
gun of the other of our allies is special and is expected to live up to
the characteristics just noted.

APPENDIX II.

STUDY OF THE RELATIVE EITICIENCY OP DIFFERENT

CALIBERS.

740. Prior to the European war guns were not constructed above
50 or at most 55 calibers length, and, in general, for greater range,
larger and larger calibers were employed. The German long-range
gun emphasized the fact that such practice did not rest on any fun-
damental theoretical difficulty in making a smaller caliber shell carry
to the greater range. The French, in their program for new guns of
greater than the previous ranges, planned on fairly small calibers,
and the question at once arises as to whether thjs is not a more
economical plan than the old one of using a larger caliber. •

741. The following calculations are based on the assumption that
it is desired to shoot a certain total weight of projectiles across a
certain range into enemy territory, and that for this purpose, on
account of the nature of the target, the number and caliber is imma-
terial (within limits), provided the total weight is the same. This
is the condition that is believed to exist for fire upon industrial
establishments, railway yards, ammunition dumps, and the like — ^in
fact, for most of the targets that are presented for destruction at
long range.

742. For this purpose, the three ranges of 10,000, 20,000, and
30,000 meters were taken, and data were obtained on French and
American guns shooting, at maximum elevation, to these ranges.

743. First, the relation between caliber and weight of piece was
studied. This relation is shown by the curves of plate 494, one
curve being given for each range. As practically no guns were found
which had a maximum range exactly that considered, a correction
had to be made in each case, as indicated on the curve, the weight of
gun was increased or decreased proportionately as its maximum
range was below or above the range in question (10,000* 20,000, or
30,000 meters).

744. Next, the relation of life in rounds and caliber was studied.
Life was computed from the Jones formula, using a corrected velocity,
obtained similarly to the corrected weight. That these values of
life are near to the absolute correct life may be seriously questioned.
But for comparison between the different guns at the larger calibers,
they are probably quite close, plate 495.

(747)

750

745. A standard of 1,000 kilograms is taken as the weight of pro-
jectile to be delivered on the target. The number of shots necessary
to accomplish this delivery for different calibers is approximately a
cube curve, and is plotted from actual values on plate 496.

746. From the preceding data, it is now possible to calculate the
weight of projectiles which each gun can deliver before it is worn out.
This is dhown on plate 497, the points representing computations
from the actual values for the preceding guns and the curves, com-
putations from values read off the previous curves.

747. It is now assumed that the entire weight of metal in the guns
is used up when it is worn out, or that it becomes ineffective. Hence,
if we compute the total weight of projectiles which can be delivered
by each caliber per 1,000 kilograms of gun wear (computed as above
noted), we have a direct measiu'e of the relative efficiency and econ-
omy of the different calibers of guns at different ranges. This has
been computed and plotted on plate 498. On this diagram there are
shown also similar curves derived from purely theoretical consider-
ations on a line of similar guns.

748. The conclusions from this are as follows:

(a) At 10,000 meters, it is much more economical to deliver a given
total weight of projectile with the smallest practicable caliber. A
given weight of 75's will deliver during their life three times the*
weight of projectiles to this range that the same weight of 400's
would deliver during their life.

(6) At 20,000 meters, the same tendency is evident but to a some-
what smaller degree. The theoretical curves indicate about 150-
millimeter caliber is most economical.

(c) At 30,000 meters, the tendency has disappeared so far as the
points from actual guns indicate, and the curve derived from pre-
vious curves indicates only a very small advantage in favor of the
smaller calibers. The theoretical curve also shows little difference,
but indicates maximum efficiency around 300 millimeters.

749. For the ranges and calibers considered for powerful railway
artillery the above would indicate that there is a most efficient caliber
from the standpoint of gun wear for each range. At the shorter
ranges (2Q kilometers) the smaller gims are most economical, but at
the longer range (30 kilometers) economy does not vary greatly with
caliber and therefore does not determine it. Very long gims of smaU
caliber would seem to have about the same economy as ghorter and
more normal guns of larger caliber carrying to the same maximum
range.

750. In order, possibly, to make clearer the steps by which the
preceding curves were derived, the table below is given of the various
values computed for the 20,000-meter curve, from a theoretical
standpoint.

181768—21 48

754

CaletUations/or tO.OOO meter range.

Gal. in inches.

Weight

Vetodty,
meters
per sec.

Velocity,
foot p. s.

4

prolectUe,

Weight

IS;

Lifegon,

KgB.

proleotUe

delivered

during

Ufe.

KgB.

delivered
Mr 1,000
Kgs. gun.

1

2

3

5

6

7

8

0

3

15

108

438

1,200

3,330

1,145
770
662
502

558

3,755
2,625
2,170
1,942
1,830

235
101
206
231
253

4,230

13,752

41,200

00,552

223,146

2,668

1,210

762

505

413

18,153

50,275

151,397

323,863

023,816

9,400

6

9,502

10

8,100

14

7,800

21

6.163

^Column 1 is assumed to give a good point distribution. Column
2 is assumed from standard projectiles. Column 3 is taken from
ballistic curves prepared by Capt. K<^nt. Column 4 is merely a
translation of column 3 to English units.

751. Column 5 is found by assuming that the same maximum
pressure, 38,000 poimds per square inch, and the same type of
expansion, giving the same average pressure, will be used on all guns.
A consideration of the mechanics of the problems will show that,
under these circumstances, the travel is equal to

Constant X weight of projectile X velocity'

caliber*

The value of the constant is found from a study of existing guns
using the maximum pressure in question and the travel is computed
from the formula and recorded as shown.

752. Colimin 6: It is assumed that the weight of any of a line of
similar guns will vary as the travel of the projectile multipUed by
the square of the caliber. A constant derived from practice is used
to get the actual weight in each case.

753. Colimm 7: The life of the g\m is computed in each case from
Joneses formula, elsewhere mentioned. In this case, however, a
correction has been applied, based on recorded lives of French guns,
so that the tendency is to lengthen the life on large calibers and shorten
it on small as compared with the values given by Jones's formula. It
is thought these revised figures are more nearly correct than those
gotten directly from the formula.

754. Column 8 is the product of columns 2 and 7 and the factor
for converting pounds to kilograms.

755. Column 9 is column 8 divided by the weight of the gun in
thousands of kilograms (derived from column 6). This figure is a
direct measure of the efficiency of the gun in delivering projectiles
to the range in question.

APPENDIX IIL

A REPORT ON THE GERMAN DEFENSES ON THE COAST OF

BELGIUM (44).

PURPOSES OF INVESTIGATION AND SOURCES OF INFORMATION.

756. The investigation on which the following report is made was
made primarily for the purpose of determining whether the Germans
had followed fixed policies in the designs of the various mechanisms
of their heavy gun carriages. With ordnance designers, there have
been a number of questions on which there has been a sharp difference
of opinion. Some believe that the cradles of heavy guns should be
heavily braced by ribs, while others feel that there is no reason why
they should not be simple smooth cylinders. Some designers are in
favor of a front pintle type of carriage with simple friction bearings,
or at best, roller bearings with racers of small diameter and more or
less crude wheels or large roUers at the rear of the carriage on which
it may be traversed. Others believe in a central pintle type of
carriage with large roUer paths. It is seen at once that there is a

vast difference in the difficulties involved in the manufacture of car- j

riages designed under these different principles. Cradles with heavy

ribs on the outside are difiScult to cast, and do not lend themselves to

rapid manufacture. If smooth cylinders will answer just as well, it

does not seem wise to hamper the manufacturer with the other design.

Front pintle carriages are in general easier to manufacture than the

center pintle type, hence unless there is something very vital to be

gained in the central pintle type of carriage with its large and

difficult to manufacture roller paths, it would seem that the first

design should have preference.

757. In this investigation, the methods of reducing the friction of
the trunnions, the designs of the elevating and traversing mechan-
isms, the ammunition supply system, as well as the design of the
guns, were studied.

758. A report has been made on these same coast defenses from the
standpoint of the problems of the coast artilleryman by Majors
Armstrong and Norton. This report is dated December, 1918, and
was published in the Artillery Journal in three parts, the last appear-
ing in August, 1919.

755

756

759. Information contained herein was secured through study
of reports in the offices of Gen. Arnoulde in Brussels, through con-
versation with Gen. Arnoulde, through inspection of all of the guns
and carriages discussed, from discussion with French ofiScers who
have inspected the same material, and from the " Renseignements de
rArtillerie*' of January and February, 1919.

760. The writer wishes to acknowledge his indebtedness to Lieut.
Gen. Arnoulde, Chief of Artillery of the Belgian Army, for the cour-
tesy extended by him for this inspection. Acknowledgment is
made likewise of the excellent service of Sergt. J. P. Ferris, who
assisted on this inspection.

mSTORY OF THE INSTALLATION.

761. The coast of Belgium was occupied by the Germans during
the month of October, 1914. They occupied Ostend on October 15,
It is probable that they at once installed some minor caliber guns
for its defense against landing parties, but the evidence available
indicates that the major caliber guns described in this report were
installed during the years of 1916 and 1917, in preparation for and
support of their major submarine campaign.

762. When the writer was with the British Fourth Army at Ypres
in February, 1918, he was told by the British ordnance officers of that
army that they had received very authentic reports to the efifect that
the Germans had been rapidly dismantling their second navy and were
mounting the gxms on railway carriages for both coast defense and land
service. The 28-centimeter guns on railway mounts that were oper-
ated in the Batteries Preussen, Hanover, and one other battery not
indicated on the map, were probably some of the guns removed from
the second navy. The emplacements for these railway mounts did
not make their appearance in the air photographs until the year 1918.

763. It is likely that the 38-centimeter gun. Battery Pommern,
near Leugenboom, was placed primarily for the purpose of bombard-
ing Dunkirk and Ypres. Both of these places were heavily shelled
by a gun of this caliber during the years 1916 and 1917. Battery
Goeben, at Zeebrugge, was made up of four complete turrets. In
this battery the original turret equipment was complete even to the
inclusion of the ammunition hoists, electrical traversing mechanism,
etc.

764. During the spring of 1918, April 23, an attempt was made to
block the harbors of Zeebrugge and Ostend. The mole at Zeebrugge
was pierced and the boat, Vindictive^ loaded with concrete, was
placed across the entrance of the Ostend harbor. The boats engaged
in these undertakings received terrific punishment, but apparently
accomplished their mission. It seems probable that had the Allies
cared to make the sacrifice, it would have been possible to force either

757

harbor, although it is not very likely that they could have retained
possession of them for any great length of time. At the time of the
inspection of these defenses, the writer observed the Vindictive
still at the entrance to the Ostend *harbor. It had been raised and
moved to a position as close as possible to and parallel with the north
side of the entrance.

765. It is significant to note that when it became necessary for the
Germans to evacuate this area in August, September, and October,
1918, the only artillery that they were able to get out was the railway
artillery. From the inhabitants of Ostend it was learned that all of
the batteries in that vicinity had been operated quite continuously
against the allied land forces for some days before the evacuation.

766. Just before the area was evacuated all the guns were destroyed
with the exception of the 38-centimeter gun at Leugenboom. One
method seems to have been employed on all of the guns for their
destruction. In most cases they removed the rotating band from one
projectile and rammed it up into the bore of the gun. A second
projectile was then rammed in and the gun fired. When the rear
projectile struck the forward projectile it exploded, and in every
case except in the Battery Ponunem, as noted above, the breech of
the gun was completely blown off and in most cases the carriage
practically wrecked. In some cases the forward projectile likewise
exploded, sweUing or tearing off the muzzle of the gun; in other cases
it was simply projected a short distance out of the gun. The guns
and carriages after being wrecked were practically valueless, and no
attempt was made to keep them in condition.

GEOGRAPHICAL PLAN OF THE DEFENSE* SCOPE OF SERVICE* ETC.

767. The distribution of the guns of various calibers along the
entire Belgian coast is shown on plate 499. Plate 500 shows some-
what better the distribution of the batteries about Ostend.

768. It is improbable that the Germans installed any considerable
number of guns along this coast until it was definitely decided to
inaugurate their major submarine campaign. It was vital that they
have a convenient base for these submarines as close as possible to
their theater of operations. The harbors at Zeebrugge and Ostend
are neither very large, but both are quite ample for submarines, and
both are connected by large canals with Bruges, where the sub-
marines could be maintained. The fortifications, hence, centered
about two ports, Ostend and Zeebrugge, with the battery Pommem
some distance out of Ostend and placed primarily for land service.
It will be noted, plate 500, that the smaller guns were all installed
upon the top of the dime that parallels the coast, while the heavy
gims were all placed a kilometer or more back of the dune. Except
for the dime, the land along the coast is quite level — ^so much so, in

758

760

fact, that it is inclined to be swampy unless well drained. The guns
on the dunes ranged from 8.8 to 17 centimeters, the 8.8 centimeter
gims being for service against aircraft. For the heavy batteries
located behind the dunes, there were heavily constructed concrete
observation stations in the dunes. The stations for the batteries
centered about Ostend were located one in front of the Royal Palace
Hotel (near the Palace Hotel Battery) and the other in the dune
near the Battery ^'Petite Irene."

769. All of the batteries shown on plate 499 by solid dots were
located on top of the dunes and were visible from the sea. Those
batteries indicated by solid dots inclosed in rings were behind the
dunes and had to depend upon the stations located in the dimes for
their observation. The Palace Hotel Battery of 17-centimeter guns
was installed on the broad promenade just in front of the Royal
Palace Hotel. This battery was particularly conspicuous. Battery
Tirpitz just south of the city of Ostend was located in very swampy
land, and it is understood that a great nimiber of piles had to be
driven to render the concrete emplacement stable. Considerable
attention was paid to the drainage of the region around this battery
and Battery Oldenbui^. All of the other inland batteries were
installed on comparatively dry and solid groimd. The Battery
Ponmiem, southeast of Ostend, was located on the eastern edge of
a small wood known as the Bois de Leugenboom. There is no evi-
dence that this battery was ever used against any except land targets.

770. Damage from Shell Fire and Bombs. — In spite of the fact
that a majority of the batteries were located on top of the dunes and
in plain sight of the sea, there is no evidence that any of them were
damaged by shell fire. It is probable that no firing was done against
the Palace Hotel Battery because of the damage that would be done
the large buildings roundabout. It is understood on good authority
that the allied ships paid constant attention to both those batteries
installed on the dunes, as well as those located behind the dunes.
As early as 1916 the exact locations of practically every battery
behind the dunes were determined from airplanes. Some of the
pictures taken of some of these batteries are shown on plates 510,
518, and 528. Other photographs are available of the remaining
inland batteries. It is understood that the monitors came in within
a few kilometers of the coast at night, camouflaging their gunfire
by blinding flares. It is reported that on practically all occasions
when the ships shelled the coast fortifications during the day heavy
smoke screens were at once set up by the Germans which evidently
afforded effective protection. Just back of the Battery Irene,
between the dime and road, the writer found a large number of steel
pots or cylinders 18 inches in diameter by 24 inches in height, which
had been used by the Germans in setting up their smoke screens.

761

The writer saw many of the holes made by airplane bombs and shown
on plate 529, but could not find any single case in which either the
inland batteries or the batteries in the dunes had been struck by
shell firing from sea or by bombs dropped by airplanes.

771. It is understood that the British monitors controlled their fire
by the scheme of triangulation. Ejiowing that the Germans would
at once set up a smoke screen between the batteries fired upon and the
monitors firing, they were in the habit of placing one boat of incon-
spicuous construction a great distance off to serve as observer. This
observing boat was so located as to be able to see behind the
smoke screen. For firing on the heavier batteries, behind the dunes,
it was of course necessary to operate by indirect fire.

772. Scope of Service. — ^The range and scope of service of the
various batteries is shown on plate 501. All of the guns, except, the
38-centimeter gun Pommem at Leugenboom, were capable of being
traversed 360 degrees. The range of 55 kilometers reported for the
Deutschland seems extreme. Various reports conflict in this re-
spect, some crediting the batteries with a range of 42 kilometers, some
with a range of 47 kilometers, and the last report, given in the Bulle-
tin Renseignements de TArtiUerie of January and February, 1019,
with 55 kilometers. The ranges given on plate 501 are in accordance
with the report in the bulletin just mentioned.

DISCUSSION OF THE MECHANISMS.
38-CENnMETER GUN BATTERY POMMERN (46).

773. Gun. — This battery, plate 502, consisted of but one gun,
model 1914, Erupp, No. 15 L. Its weight is 77,530 kilograms,
over-all length 17.13 meters, and length from breech block to the
muzzle, 16.13 meters, giving it an effective length of 42 calibers. It
seems to be rated in some reports as a 45-caliber gun. This rating is
evidently based on its over-all length. There are 100 grooves, and
the twist of the rifling is to the right 1 centimeter in 10. The diame-
ter of the powder chamber is 42.5 centimeters, and the outside diame-
ter of the breech 1 meter. The breech is of the usual Krupp sliding
wedge type and its mechanism is identical with that on the 38 centi-
meter gun on the railway moimt. The design of the gun is likewise
identical with that of the gun on the railway mount, and with the 38-
centimeter guns of the battery Deutschland, plate 506. On this plate
it will be observed that the breech section has been blown away.
The scheme of attaching the breech section by the interrupted ring
method is well shown. As in the case of the railway mount, the recoil
lug has a bearing at the bottom on the two sides of the recuperator
cylinder to prevent rotation of the gun.

774. Cradle. — ^The cradle is a cylinder of simple design, having
ribs at long intervals and a depth of only about 3 centimeters. The

762

s

764

walls of the cylinder have a minimum thickness of 10 centimeters and
a maximum thickness of 13 centimeters over the ribs. The diameter
of the main trunnion, plate 503, is 46 centimeters and the length 33.5
centimeters; the diameter of the small trunnion 20 and the length 19
centimeters. It will be observed that the antifriction mechanism
is of the rolling wedge type. This cradle was provided with a counter-
weight identical with that shown on plate 506, and its front is so de-
signed as to close the opening in the turret. Its total length is 3
meters, and it is provided with brackets for the recoil and recuperator
cylinders on the bottom as shown in plate 403. The cradle is lined
with a bronze liner, approximately 6 millimeters thick and 1 meter
in length both at the front and rear. A portion of this liner may be
seen on plate 506.

775. Recoil Mechanism. — For the description of the recoil mech-
anism, see '* Recoil mechanism'' of the 38-centimeter gun on the rail-
way mount. The two recoil cylinders, plate 403, are carried in brack-
ets on either side and the filling plugs are on the ends of the buffers.
The recuperator cylinder is carried in the center in similar brackets
and likewise has a filling plug on its forward end. As mentioned be-
fore, its rear end, which is planed on both sides, serves as a guide for
the breech lug to prevent rotation of the gun.

776. Elevating Mechanism. — See the same for the 38-centimeter
guns of the Battety Deutschland. The only difference between the
two is that in this battery there was no provision for hand operation.
The report found in Gen. Amoulde's office stated that this gun had
been originally provided for hand operation only, but that within the
last year it had been equipped with motors for electrical operation.
The maximum elevation obtainable is 45 degrees.

777. Traversing Mechanism. — See description of the traversing
mechanism of the Battery Deutschland. There is provision for both
hand and power operation of this mechanism. The wheel for hand
operation, however, is located on the left of the carriage very close to
and on a level with the traversing rack. It is 1 meter in diameter.
The maximum traverse provided for is about 1 57 degrees. The center
line of this field of fire passes approximately through Dunkirk.

778. Carriage. — See detailed description of the carriage for the 38-
centimeter guns of the Battery Deutschland. The only difference
between these carriages is in the armor provided on the guns of the
Battery Pommem. This will be described later under the head-
ing of ' ^ Protection. ' '

779. Emplacement. — ^The emplacement for this carriage is of ex-
ceedingly massive concrete construction. The diameter of the cen-
tral pit or well in which the carriage is placed is approximately
22.439 meters. The form of the pit is not a complete circle, but is
so shaped as to allow the carriage to traverse 157 degrees. The

765

i

766

depth to the level of the traversing rack is 3 meters and the addi-
tional depth to the floor on which the center pintle rests 1.5 meters,
making a total depth of 4.5 meters. On either side are practically
identical concrete structures for the housing of ammunition and per-
sonnel. The structure on the right is for projectiles and tools. Be-
tween these two structures at the front, plate 502, there is a con-
crete parapet 2 meters high and 3 meters thick. The earth slopes
gradually away from the top of the parapet at the front, drop-
ping about to the level of the main floor of the emplacement on
which men are seen standing. The thickness of the roof of the struc-
tures on the right and left is 3 meters, the total height above the
floor being 5.5 meters.

780. Ammunition and AMMUNmoN Supply System. — As just
noted under the heading of ' 'Emplacement'' the projectiles were
stored in the concrete storehouse on the right and the powder in the
storehouse on the left. Three weights of projectiles were used, one
of which is shown on plate 504. This projectile has a false ogive.
The ammunition was supplied entirely by hand, the shot truck being
of the design shown on plate 505. The arrangement of the store-
house is in general similar to that for the 305-millimeter gun of the
Battery Kaiser Wilhelm II, plate 517, the projectiles being piled
two high. Gen. Amoulde's report states that the projectiles were
rammed by 12 men and that the rate of fire was one shot in five
minutes with electrical operation of the elevating mechanism, and
one shot in 10 minutes with hand operation of the elevating mecha-
nism. Gen. Amoulde's report further states that according to reports
of people living at Leugenboom, the personnel originally provided
for operation of the moimt when it was operated by hand was 1
captain, 2 lieutenants, 10 noncommissioned officers, and 160 men.
After provision was made for electrical operation of the various
mechanisms, the personnel was reduced to 1 captain, 2 lieutenants,
5 or 6 noncommissioned officers, and 70 men.

781. The shells fired by the 38-centimeter gun are:

Name.

Weight.
760 kg

Fuse.

Range.

H. E. 38CII1. Sp. Qr. L/4.1 Bds., with base fuse.
H. E. 38cm. Sp. Or. L/3.6 m. Bd*. (mHaube),

with false ogive and base fuse.
H. E. 38 cm. Sp. Or. L/4 Bdz. A. Ke

(mUaube), with double fuse M head and

base false ogive.

Sp. Grm. K

Sp. Orm. K

Sp. Orm. K

42 km.

095 kg. (600 without false

ogive).
342 kg. (without false ogive).

44 km.
48 km.

The charges are three in number:

(a) Hutzenkartasch, cartridge containing 87 kg.
(6) Vorkartasche, charge containing 96 kg.
(c) Vorkartasche, charge containing 118 kg.

'67

3
IS

181768—21-

49

768

to

s

i

^

s

~j^^oy

769

It seems then that the gun can fire with two charges; that is:

(1) 87 kg. plus 118 kg. = 205 kg.

(2) 87 kg. plus 118 kg. plus 96 kg. =-- 301 kg.

782. Protection. — ^To protect the personnel operating this gun
against aircraft bombs and aircraft machine-gun fire, the carriage
was covered with 6-centimeter flat armor. This plating extended
to wnthin a few centimeters of the floor of the pit. The hole in the
front through which the guns extend is sealed by the small shield
on the front of the cradle.

783. Discussion. On plate 502 it will be observed that the para-
pet just in front of the gun has been blown away in the center.
There is evidence to the effect that the Germans used their char-
acteristic method in attempting to destroy this gun, but that in this
case neither projectile detonated until they struck the parapet in
front. Neither projectile could be found, hence it is assumed that
both detonated. The gun was damaged only to a slight extent at
the muzzle, where some fragments of the projectiles were blown
back into the bore, scoring it deeply.

38-CENTIMETER GUNS, BATTERY DEUTSCHLAND.

784. Gun. — See description of the 38-centimeter gun of the Bat-
tery Pommern. The design of these four guns is identical with the
design of the model 1914 Krupp gun, No. 15-L. The gun, plate
506, is a model 1916, No. 36-L. Its weight is given as 77,562 kilo-
grams. This gun is No. 4 of the battery; No. 3 is likewise a model
1916, and numbered 35-L. Gun No. 2 is model 1916, No. 41-L,
and gun No. 1 is model 1914 No. 9-L.

785. Each of these guns had been destroyed by the characteristic
German method of placing one projectile in the bore of the gun and
firing another projectile into it. This procedure had resulted, in.
this case, in the blowing off of the entire breech and in the wrecking
of the carriage. There was little evidence that any of those guns had
been used to any great extent. The lands and grooves were in
well-nigh perfect shape; at least, it was evident that such damage
as was visible had not been caused through ordinary fire. The
width of the lands is 6 millimeters, and the depth of the grooves 3
miUimeters. In connection with the procedure in destroying the
guns, reference is made to plate 532, on which is shown one of the
projectiles from which the ))and had been removed. This projectile
was found beside gun No. 3.

786. Cradle. -The cradle on each of these four guns is identical in
design with that of the 38-centimoter gun of the Battery Pommern
and of the 38-centimeter gun of the railway mount. The counter-
weight on the cradle of the railway mount is collapsible. The
counterweights on the Battery Pommern and Battery Deutschland
cradles are as shown on plate 506. The one point of difference be-

771

tween the cradles of throe of these guns and the cradle of the gun on
the Battery Pommern is in the lack of any provision for the reduction
of the friction of the trunnions. On plate 506 it will be observed that
there are no auxiliary trunnions and no friction reducing mechanism.
There was no friction reducing mechanism on guns Nos. 2, 3, and 4,
but gun No. 1 had a friction reducing mechanism identical with that
of Battery Pommern, plate 503. This omission of anti-friction de-
vices on guns Nos. 2, 3, and 4, which, by the way, are model 1016
guns, can hardly be attributed to the lack of time for the installation,
since the small amount of machine work necessary in the shop might
have been handled without difficulty, and the work finished in the
field if desired. Apparently they preferred to rely on a*surplus of
man power in elevating their guns.

787. Recoil Mechanism. — The recoil mechanism is composed of
two recoil cylinders and one spring pneumatic recuperator cylinder
all located at the bottom of the cradle. It is identical in design with
the recoil mechanisms of the Battery Pommern gun and the 38-
centimeter railway mount, plate 404.

788. Elevating Mechanism. —The elevating mechanism on all
of these guns, as well as on the 3S-centimeter gun of the Battery
Pommern, is composed of two large telescoping screws, the larger
screw passing through a nut carried in the crosshead at the bottom
of the cradle, plate 506. On this plate the larger of the elevating
screws can be seen about in line with one of the elevating and traversing
handles at the bottom of the carriage. The larger of these two screws
is about 24 centimeters in diameter and the smaller about 15 centi-
aietors. The large nut in the crosshead is driven either from the
motor, or bv the hand mechanism which is used likewise for the
traversing mechanism.

789. The maximum elevation at which the gun is operated is not
known. There were no elevating arcs remaining on any of the cradles
that would indicate to what extent it could be elevated. It is
asaumed, however, that the maximum elevation obtainable is the
same as that in the Battery Pommern gun, which is 45 degrees. On
plate 506 the motor driving the elevating and traversing mechanisms
is hidden by the wire camouflage which has fallen. The box just to
the rear of the camouflage is the housing for the clutch connecting
the elevatins: mechanism with either the motor or the hand drive.
All of this mechanism is duplicated on the left side of the carriage.

790. Traversing Mechanism.— The various details of the trav-
ersing mechanism are shown on plates 507 and 508. Provision is
made for its operation by hand as well as by motor. This hand
mechanism is operated by eight men.

'791. The rear of the carriage is supported on two heavy rollers
96 centimeters in diameter by 23 centimeters on the face, which are
carried on 21-centinietor spindles. A complete circular steel bearing

^^ »«£/

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773

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774

plate is bolted to the first shelf of the pit. This plate is 12 centi-
meters thick by 1 meter in width and to its outer edge, plate 509, is
bolted a traversing arc made of 3 angles and a series of 5-centimeter
steel pins. The star traversing pinion, 21 centimeters outside diam-
eter, meshes with this rack and is driven by either the motor or the
hand mechanism. The radius to the center of the traversing rack
is 10.439 meters."

792. Carriage. — The carriage is entirely of structural steel, plate
506. It is of the front pintle type, the front being carried on st^el
balls. The ball path is 2 meters in diameter and the balls 15 centi-
meters in diameter. It is assumed that some provision is made for
direct contact between the racer and base to transmit the horizontal
component of the force of recoil into the foundation. It was not
possible to see the details of construction to confirm this supposition.
Examination of some other carriages of similar design indicated that
at least in some cases the racer was simply permitted to climb the
balls when the gun was fired, no provision being made for positive
contact. As noted under '^Traversing mechanism," the rear of the
carriage is supported on two rollers 96 centimeters in diameter.
These rollers have a face of 23 centimeters and are carried on steel
spindles 21 centimeters in diameter. The distance between the cen-
ters of these journals is approximately 3.3 meters. The rollers
app3arod to be perfectly cylindrical, with rounded edges. The con-
struction of this carriage for one of their heaviest guns is exceedingly
simple. The only heavy castings are those for the pintle, the elevating
cross head, and the trunnion bearing. The only parts of the entire
mechanism wliich obviously require fine machine work are the
trunnion bearings, the heavy steel balls, and the ball paths.

793. Emplacement. — With the omission of the heavy concrete
structures described under Battery Pommern for ammunition and
personnel, the emplacements for the Batteries Pommern and Deutsch-
land are nearly identical. Battery Pommern was finally fitted up
for electrical operation only, and most of the mechanism for hand
operations is removed. In the lower part of the Battery Deutschland
pit a wood floor made up in sectors raised the floor to such an extent
that the men operating the traversing and elevating mechanisms
would be on the proper level. As seen in plate 506 the pit was filled
with water at the time of the inspection to such an extent that these
sectors had come loose and were floating. The emplacement provided
for 360 degrees traverse of the carriage as against 157 degrees for the
Battery Pommern.

794. Ammunition Supply System. — See description of the ammuni-
tion supply system for the Battery Pommern. There was no evidence
of any provision of any mechanical handling of the projectiles except
in the lifting of them from the floor to the storehouse and placing

77r)

&4

776

them on the shot trucks. Between guns Nos. 2 and 8 of this battery- ,
there was found a practice shell ramming tray somewhat similar to
that shown on plate 517 for the Battery Kaiser Wilhelm 11. This
tray was made of a steel trough about 10 feet long with an oi'dinary
railway car buffer at the end. In the tray there was a rather blunt
nosed projectile \^dth its rotating band removed. This projectile
had evidently been used for practice in ramming.

795. Protection. — It is significant to note with reference to the
three of the newest of these guns, that is, Nos. 2, 3, and 4, that there
was absolutely no protection provided either for the gun carriage or
personnel. Evidence of their scheme of camouflage c&n still be seen
on plate 506. This camouflage was unable to hide the guns from the
air photographers since photographs taken on August 9, 1916, plate
510, showed the emplacements quite plainly. In spite of this fact,
there was no evidence to the effect that any of the guns or emplace-
ments had ever been damaged by either shell fire from sea or by
bombs from the air. Several holes that had been made, either by
bombs or by shells, were visible in the fields in front of the guns.
Gun No. 1 was protected with 6-centimeter armor in the same fashion
as the gun of Battery Pommern. Gun No. 1 of this battery and th^
28-centimeter gun of the Battery Ponmxem are identical in design
throughout. Both are model 1914 guns, and it is probable that the
hand elevating and traversing mechanism of the Pommern gun was
identical with those of the Deutschland guns before the electrical
equipment was provided.

796. Discussion. — Significant points with reference to this battery
are that guns Nos. 2, 3, and 4 a^e not provided with either trunnion
antifriction device or positive protection in the form of steel armor.

305-MILUMETER GUN, BATTERY KAISER WILHELM IL

797. Gun. — With each of these four guns, plate 511, the scheme
of destruction was so eff^ective that it was impossible to find a breech
after a half day^s search. It is assumed that they were of a model at
least as late as 1916. The Bulletin de Renseignements de TArtillerie
states that they were 50 calibers in length. One breech block was
found ; this was of the usual Krupp sliding wedge type. There were
88 grooves and the twist of the rifling is to the right 1 centimeter in
10 centimeters. Projectiles found in the storehouse and shown on
plate 574 have two rotating bands from which it may be assumed
that the pitch of the rifling is uniform.

798. Cradle. — The cradles for all of these guns are smooth cylin-
ders, the walls of which are 10 centimeters thick. The brackets at the
bottom of the cradle provided for the recoil and recuperator cylinders,
are quite similar to those shown on plate 419 of the 38-centimeter
gun. The front of the cradle is provided with shield, plate 552,

B PHOTOGRAPH OF THE GERMAN' ISCM. BATTERY DEUTSCHLANO (TAKEN

779

which closes the opening in the armor; it is not improbable that these
were likewise some of the guns removed from the second navy.
The cradle is likewise provided with a heavy counterweight which
can also be seen on plate 403. The antifriction device, plate 512,
is of the rolling wedge type. It is significant that in this case the
auxiliary trunnion is very little less in diameter than the main
trunnion. In practically all other cases observed, the diameter of
the small trunnion was approximately one-half of the diameter of
the large trunnion.

799. Recoii. Mechanism. — The recoil mechanism for this gun is
in general a duplicate of that shown on plate 403 for the 38-centimeter
gun. The breech lug with the method of attaching the recoil pistons,
and the bearing of the lug on the recuperator cylinder to prevent
rotation of the gun are shown on plate 515. In contrast to the
38-centimeter gun in which the recoil pistons pass through holes in
the recoil lug and the recoil lug bears on two planed sides of the
recuperator cylinder, it will be observed in this case that the lug is
slotted on the sides to receive the recoil pistons and the bearing on
the recuperator cylinder is circular instead of flat.

800. The outside diameter of the recoil cvlinder is 38 centimeters
and the length is 1.68 meters. The diameter of the piston is 15
centimeters and th^^ length of recoil 1.37 metei's. These cylinders
are both smooth forgings with flanges at the front bearing against
the cast bracket on the cradle. There was no evidence of a counter-
recoil buffer. On the front end of the cvlinders, there are fillius:
plugs similar to those found on the 38-centimeter cradles. The
single recuperator cylinder is likewise a smooth forging with one
large flange on its forward end. It is of the combine<l air-spring type
and is approximately 45.6 centimeters in diameter by 4.25 meters in
length. This cylinder likewise has a filling plug at the front end.

801. This is a timely opportunity to mention a fact that seems to
the writer quite striking. Although the Germans follow, in general,
fixed policies in their designs, their methods of application differ very
widely. Apparently general specifications are given to the manu-
facturers who are permitted to modify them in details to suit their
convenience. It does not seem probable that any designer or groups
of designers would make such radical differences in the design of the
details of their mechanisms as is evident on these guns and carriages.
This is even more striking on their 21, 24 and 28-centimeter railway
mounts.

802. Elevating Mechanism. — The elevating mechanism for
these guns is in principle the same as the elevating mechanism for
the 38-centimeter railway mount. The design of its details are, how-
ever, quite different, plates 513 and 514. Apparently it was oper-.
ated entirely by hand. There are two two-man handles below the

780

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781

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04

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782

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783

deck of the carriage for rapid elevation and above the deck a single
handwheel of large diameter for final and careful setting. The clutch
for shifting from the low gear to the high is located below deck. Motion
is transmitted from the handwheels to the horizontal shaft at the
bottom and through the bevel and helical gears to the two pinions
on the main horizontal elevating shaft. The two straight racks,
which in this case are horizontal, plate 513, are connected to the cross-
head which slides on a single roimd shaft as a guide. This crosshead
in turn transmits motion to the gun through the two connecting rods.
The two racks have guides on the top which slide in ways in the for-
ward support of the main horizontal guide shaft, plate 554. It was
not possible to elevate the gun, and the ratio of the gearing is not
known. This mechanism, together with its companion mechanism
on the 38-centimeter railway moimt, are quite unique among the
mechanisms observed on all German artillery. The reasons for the
design seen on the railway mount seem obvious, but the same reasons
do not hold for this carriage. Certainly, a simpler mechanism of equal
eflBiciency could have been provided. The maximum elevation ob-
tainable is 45 degrees.

803. Travebsing Mechanism. — ^The traversing mechanism, fig-
ures 1 and 2, plate 515, is* operated both by hand and motor. The
roller track set in the concrete emplacement is shown in figure 1.
In this case, contrary to the design of the same mechanism for the
Battery Pommern and Deutschland, there is no traversing rack pro-
vided in connection with the roller track. Motion is transmitted
through chains and gears from the motor or handwheel to the travers-
ing pinion which meshes with the two gears bolted to the faces of the
traversing rollers, figure 2. The simplicity of this mechanism is very
striking, especially for guns of this size. Apparently, it worked satis-
factorily, or it would not have been retained in a gim of such value.
It is certainly worthy of serious consideration for similar carriages
for our own service. An azimuth circle is embedded in the vertical
walls of the concrete emplacement about 2 feet from the top, plate
512. An indicator is provided on the rear of the carriage, with a
vertical wire quite close to this azimuth circle. The switchboard
and seat for the traversing operator are located beside this indicator.

804. Carriage. — ^The carriages are constructed entirely of struc-
tural steel. The side girders are in three main sections, comprising
a central section of uniform depth, a top brace for the trunnion sup-
port, and a bottom section for the pintle, plate 511. The pintle
design is shown in figure 1 of plate 515. It is ball bearing, the balls
being about 15 centimeters in diameter. In this case the racer serves
as a pintle, having a positive bearing against the base ring for the
transmission of the horizontal component of the force of recoil into
the foundation.

181768—21 50

ISi

785

805. Ammunition Supply System. — The general plan of the Bat-
tery Kaiser Wilhelm II is shown on plate 516. Storehouses are located
on the left of each gun and the main storehouse is 100 meters to the
left of the battery. The narrow-gauge line shown extending from the
main storehouse, passes through each auxiliary storehouse. A typical
plan of one gun and its storehouse is given on. plate 511. The double

, narrow-gauge lines shown passing through the storehouse are the
same as those shown on plate 517. These storehouses are of excellent
construction and are typical of the design of the storehouses for most
of the heavy batteries inspected. The plan for the Battery Deutsch-
land was almost identical. The external plan for the Battery Pom-
mern was slightly different, but the interior arrangement was well
nigh the same.

806. Projectiles are transported from the main storehouse to the
individual storehouses on narrow-gauge railway trucks. From these
trucks they are carried by means of an overhead trolley through
openings in the walls into the projectile rooms, where they are stacked
two high. Later they are picked up and carried by the same trolley
into the corridor just outside the shell room and placed on the shot
trucks, figure 4, plate 514. The table of this truck is quite broad and
the sheU is placed on one side where it is held by two arms until it is to
be rammed. The truck is provided with a shelf, presumably for pow-
der. There was no evidence of any scheme of handling the ammu-
nition except by hand. The rammer foimd beside one of the guns is
of such a length as to indicate that the projectile was probably
rammed by eight men. The guns are loaded at zero elevation. An-
other practice shell-ramming tray, plate 517, was found beside one
of the emplacements.

807. Emplacement. — The design of the emplacement for these
guns is shown on plate 511. It will be observed that all the space
about the gun leading to the ammunition storehouse is floored with
concrete. In this respect the emplacement differs from that of the
Battery Deutschland in which the concrete work did not extend much
beyond the vertical walls of the pit. It is not known just why the
walls of the pit are higher in front than in the rear. There seems to
be no particular reason for it. The depth of the pit to the roller path
is 2.4 meters, and the total depth 3.6 meters.

808. Protection. — Each of the four guns of this battery is pro-
tected with (3-centimeter flat armor. The guns and carriages were
likewise elaborately camouflaged to hide them from the sight of the
airmen, but air photographs taken on August 9, 1916, plate 518,
indicate that it was perfectly possible to see the emplacements. In
spite of all this there was no evidence that any of these guns, car-
riages, or emplacements had ever been damaged by shell fire from sea
or by bombs from airplanes. Some holes were visible some distance

787

I-

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789

in Tront of the emplacements which may have been made by either
bombs or shells. A few similar shell holes were visible some distance
to the rear.

28-CENnMETER GUN RAILWAY MOUNT, BATTERY PREUSSEN.

809. Gun, Cradle, Recoil Mechanism, Elevating Mech-
anism.— See description of the same for the 28-centimeter Railway
Mount, paragraph 367 to 380.

810. Traversing Mechanism. — A description of the details of the
mechanism attached to the mount is given under the description of
the traversing mechanism for the railway mount. The writer had
not had the opportunity to exfimine the concrete emplacement at
the time the description of the railway mount, plate 386, was written.
The emplacement shown on plate 519 is typical of the 12 emplace-
ments provided for the three 4-gun batteries along the Belgian coast.
There was a steel plate on top of the central base section which was
blown off when the Germans were demolishing their fortifications.
The standard-gauge track extends a short distance beyond the
emplacement, for the forward truck when removed from the mount.
It was mentioned under the 28, 24, and 21 centimeter railway mounts
that the carriages were so designed that they could all be used on
the same emplacement.

811. The auxiliary sections of track that are laid inside the emplace-
ment for the placing of the gun are shown on plate 519. As soon as
the gun is in position, the central sections of rail, one piece of which is
shown removed, are removed and the. base section of the pivot
dropped and bolted in place. The carriage is then raised a few
inches by means of the jacks shown with the mount, plate 386, and
the trucks removed. The short sections of track within the emplace-
ment are likewise removed and the rear of the carriage let down
until the traversing rollers rested on the roller path.

812. Carriage. — The details of design of the carriage have been
fully described in paragraph 373.

813. Emplacement. — The various details of the emplacement are
shown on plates 519 to 521. The two short central sections of rail,
figure 1, plate 520, are connected by a steel plate which rests on top
of the base for support as the mount passes over. Some curious
markings on the vertical wall of the pit are shown on plate 521. The
central vertical line is obtained approximately by passing through
the center of the emplacement a line perpendicular to the general
line of the coast. The distance between the vertical graduations
labeled 0-50 and 50-100 is about 2 feet, and the total angular dis-
tance covered from the center to the graduation 250 is about 60
degrees. A complete azimuth circle was found painted at the outer
edge of the roller track. This circle, however, could not have been

792

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793

used, except for the approximate laying of the gun, since it was not
made with sufficient accuracy. It seems more probable that the
mount was laid in azimuth from some aiming point.

vS14. The general location of the emplacements with reference to
the main railway line on which the mounts were brought in and like-
wise with reference to the coast line is shown on plate 522. Two spur
lines were run in from the main line. 7t is not quite clear why this was
done; it would obviously have been possible to run short lines to the
two guns on the left from the spur line in the center connecting the
main line with the two guns on the right of the plate.

815. Ammunftion Supply System. — The location of the ammuni-
tion storehouses and the narrow-gauge connection with the emplace-
ments is shown on plate f 22. ! n each case the standard-gauge line
runs at the rear of the quite simple concrete storage houses which are
provided with two doors both at the front and at the rear, plate 523.
The powder is kept in the one storehouse and the shells in the other.
A double line of 30-centimeter track connects the storehouses with
the two emplacements. These narrow-gauge lines connect with turn-
tables just inside the wicker protection. A complete circle of narrow-
gauge trac\c is provided about each emplacement, making it possible
to supply the shells to the mount in any position. There was no
evidence of any scheme of storing the projectiles or powder closer to
the mounts than the storehouses. Evidently a sufficient number of
shot trucks are provided for these narrow-gauge lines that the shells
can be provided directly from the storehouses at the maximum firing
rate of the gun. The ammunition storehouses were well camouflaged,
plate 522, but in spite of this camouflage air photographs taken in
1918 indicate clearly the position of all of the guns as well as the
storehouse.

816. Protection. — The gun crew was protected to a certain
extent by the light sheet metal cab on the mount, plate 38(5. The
mounts were likewise well screened with wire and brush, remains of
which can be seen on plate 519. In spite of this camouflage air
photographs showed quite clearly the positions of the emplacements.
There was no evidence of damage from shell fire or air bombs on the
emplacements or storehouses. A heavy concrete headquarters
shelter with telephone connections from the observation stations in
the dunes and telephone connections to the various guns was provided
between the pairs of guns. In each case there is a cable through the
central pintle base which evidently carries the telephone connections
between headquarters and the mount.

28-CENTIMETER GUN. BATTERY TIRPITZ.

817. Gun. — Battery Tirpitz is a four-gun battery and all of the
guns are of model 1911. The gun of the four which was examined
in detail was model 1911, No. 5. Its weight is 33,875 kilograms.

794

AMMLNITION STOREHOUSE OF THE 2W:m, RAII.WAY BATTERY PREUSSEN.

796

The length of the tube from the face of the breechblock to the muzzle
is 11.220 meters, and the over-all length of the gun is 11.950 meters.
There are 80 grooves, and the twist of the rifling is to the right 1 cen-
timeter in 10 centimeters. The diameter of the powder chamber is.
30 centimeters. The breech is of the usual Krupp sliding wedge
type. As with the 38-centimeter gun found on the railway mount,
the tube of this gim has lengthened from firing, thereby separating
the forward hoop a noticeable distance from the hoop to the rear,
plate 524. Apparently, these hoops are not locked to each other.
The lower extension of the breech lug, plate 525, is machined to bear
against the planed inner surfaces of the lower recuperator cylinders,
thereby preventing rotation of the gun. The gun did not show
signs of very great wear, both the lands and the grooves being quite
sharp.

818. Ceadle. — ^The cradle is a smooth cylinder, the walls of which
are 10 centimeters thick. It is lined with bronze liners about 6
millimeters thick by 1 meter in length, at both the forward and rear
ends. The trunnions are located noticeably close to the forward
end. The antifriction device is of the rolling wedge type illustrated
on plate 511. There were no unusual features in this design, and
no sketch has been made.

819. Recoil Mechanism. — ^The recoil mechanism, plate 525,
comprises two recoil cylinders located on the top and bottom of the
cradle and four recuperator cylinders. The two recoil cylinders are
smooth forgings carried in the cast brackets on the top and bottom
of the cradle. Their length, not including the buffer, is 1.22 meters,
and the length of the buffer is 24 centimeters. The piston rods,
11.5 centimeters in diameter, pass through holes in the extensions of
the breech lug. The length of recoil is approximately 76 centimeters.
The four recuperator cylinders are placed symmetrically above and
below; the upper cylinders are combined spring and air recuperators,
while the lower are spring only. A common air line is connected to
the valves on the forward ends of the upper two cylinders. It is
believed that the air is supplied from bottles since there was no
evidence of an air pump about the carriage. Both above and
below, two rods connect the extensions of the breech lug with the
crossheads attached to the piston rods of the recuperator cylinders.
These rods taper from 4 centimeters at the crosshead to 5 centimeters
at the breech lug, and are turned down to 4 centimeters through the
breech lug. This design strikes one as being close to the limit of
safety as it placed these rods, which are not of very great diameter,
always under compression.

820. Elevating Mechanism. — The general design of the elevat-
ing mechanism is shown on plate 52G. It is operated by hand power
only and the ratio of the gearing, as indicated, is five turns of the

181768—21 51

800

handwheel for four degrees of elevation. The elevating rack is
double, although cast in one piece. Identical pinions on the same
shaft and of the dimensions shown mesh with these racks. The
range of elevation is from zero to 45 degrees.

821. Traversing Mechanism. — The traversing mechanism is
quite similar to that found on the guns of the Battery Kaiser Wil-
helm II. Details of this traversing mechanism are shown on plate
527. As with the 305-millimeter battery, there is no traversing rack
attached to the roller path. The operation is by hand only from a
large handwheel located on the left side of the carriage and about on
a level with the roller path. In the case of the 305-millimeter car-
riages the single pinion meshed with spur gears attached to the face
of the two large rollers. In this case, the motion from the large
handwheel is transmitted directly to only one of the four rollers on
which the rear of the carriage is supported. Although the mechanism
was seriously damaged, it was possible to traverse the carriage just
far enough to indicate that one man could operate the mechanism
without difficulty.

822. Carriage. — ^It was not possible to secure such a photograph
of these mounts as would show satisfactorily the construction of the
carriage. In general, the design is not unlike that of the carriages
for the 305-millimeter guns. There are two main girders, each of
which is in three sections, a central section of uniform depth, a top
section for the trunnion support, and a bottom section carrying the
pivot. It is made of standard structural plates and angles through-
out. The racer is attached to a heavy yoke which is supported by
its trunnions in heavy trunnion bearings attached to the carriage.
The design of the racer connection with the carriage is not at all
unlike that found on the 28, 24, and 21 centimeter railway mounts.

823. Emplacement. — The emplacement is quite similar to that
already described for the 305-millimeter guns. The traversing
roller path is practically identical and the general dimensions of the
pit are nearly the same. Again there is a raised section of concrete
in front of the gun, the purpose of, or necessity for, which is not
clearly understood. It is imderstood that imusual difficulties were
encountered in constructing these emplacements, inasmuch as the
ground is quite swampy, and it was necessary to drive numerous
piles in order that the emplacement might be sufficiently stable.

824. Ammunition Supply System. — The ammunition supply sys-
tem for this battery is quite similar to that shown and described for
the 305-millimeter gun. The shot trucks are of the same design.

825. Protection. — Each of these four guns is armored with 6-
centimeter flat armor. In spite of the camouflage, the remains of
which can be seen on plate 524, legible air photographs were secured
on August 9, 1916, plate 528. The camouflage is carried on a frame-
work attached to the carriage and rotates with it. Most of the con-

801

803

Crete work about the guns is completely demolished, but there is no
evidence that would indicate to the writer that any of the destruction
had been effected by shell fire from the sea. It is certain at least
that none of the carriages had been so struck or damaged. There
are numerous holes to the front and rear of the batteries that were
probably made by air bombs.

28-CENnMETER MORTAR BATTERY GRODEN.

826. Top Carriage. — ^These mortars are supported directly by
means of trunnions on a structural steel top carriage of the design
shown on plate 529. This carriage was supported on the inclined
sides of the main carriage by means of four rollers, two on each side.

827. Recoil Mechanism. — ^The recoil mechanism, which does not
show very clearly on plate 529, comprises two recoil cylinders, the
pistons of which were attached to the forward ends of the main
carriage body; the cylinders are carried in the sides of the top car-
riage. The length of recoil is estimated as 1 meter, the gun returning
to battery by force of gravity. On the front of the main carriage,
there are four buflfers, each made up of seven pairs of Belleville
washers, 15 centimeters in diameter by 6 millimeters in thickness.

828. Elevating Mechanism. — The elevating mechanism comprises
a single circular rack bolted to the gun and iheshing with a single
pinion on a horizontal shaft in the top carriage. The hand wheel
operating the elevating mechanism is located on the right side of the
carriage on a platform rotating with the carriage. On the end of
the horizontal shaft in the top carriage, there is a worm wheel meshing
with the worm carried on a long shaft parallel to the inclined rails
on which the top carriage rolls. The worm is simply keyed to the
shaft, moving with the top carriage as it recoils. This is the only
elevating mechanism observed in which a slip friction device is pro-
vided. This slip friction device provides for the slipping of the worm
on the end of the horizontal shaft through the top carriage. It
includes two sets of Belleville washers.

829. Traversing Mechanism. — ^The traversing mechanism is made
up of one rack attached to the base ring, a traversing pinion, vertical
shaft, and simple spur gear mechanism leading to the handwheel.
There is nothing unusual in the design and from the condition of the
carriage, it was impossible to traverse it to learn the ratio of the
gearing. The extent of traverse is 360 degrees.

830. Carriage. — It is believed that the carriage is shown in such
detail on plate 529 as to make any lengthy description unnecessary.
The diameter of the ball path is 3.5 meters, and the balls are about
10 centimeters in diameter. The carriage is constructed throughout
of standard structural steel.

831. Emplacement. — ^The pit is 6 meters in diameter, and 1.5
meters in depth. In front of each mortar there is a concrete parapet

805

about 5 meters high, having a slope of about 45 degrees. A part
of this parapet is shown at the left foreground of plate 529, and is
evidently a continuation of the concrete storehouse which is covered
v^ith earth.

832. Ammunition Supply System. — ^The ammunition supply
system is shown on plate 529. Between the shell table and the road,
a narrow gauge line can be seen, which leads to the main storehouse.
At the end of the shell table on the concrete floor there are guides to
place the shot truck in loading projectiles from the table. It is
assumed that the mortars were loaded at zero elevation, although
this is not certain. The shot truck is similar in design to those used
with the 38-centimeter guns and shown on plate -505. Since the
powder charge was not of great weight, it is probable that it was
carried in a two-man tray.

833. Protection. — ^The only protection afforded these mortars
has been mentioned under "emplacement." There was no evidence
of any camouflaging, although it is assumed that some sort of camou-
flage was provided. Air photographs taken in 1916 repealed the
presence of these mortars, and it is quite certain that no amount of
camouflage could effectively conceal them. There is no evidence,
however, that any of them had ever been either struck or damaged
by shell fire or bombs.

17-CENTIMETER GUN, BATTERY GOEBEN.

834. Gun. — ^AU of the guns of this battery, plate 530, are model
1914, and the gun examined in detail is model 1914, No. 71-L. Its
weight is 10,701 kilograms, the length of the tube 6.44 meters, and
the total length of the gun is 6.980 meters. There are 52 grooves,
and the twist of the rifling is to the right 1 centimeter in 10 centi-
meters. The diameter of the powder chamber is 19 centimeters and
the breech is of the standard Krupp sliding-wedge type.

835. Cradle. — ^The cradle is identical in design with the cradle
found with the 21-centimeter railway mount. There are two hy-
draulic buffer cylinders, one on the top and the other directly below
the cradle, and each is attached to the cradle by a heavy pin, about
which it can rotate in a vertical plane. Four spring cylinders are
arranged about the cradle symmetrically, two above and two below.
The design of this type of cradle is shown on plate 374. The diameter
of the trunnions is 22 centimeters and the length 15 centimeters.^
The antifriction device is of the design shown for the 15-centimeter
guns on plate 535.

836. Recoil Mechanism. — The outside diameter of the recoil
cylinder, plate 531, is 25 centimeters and the estimated length of
recoil 40 centimeters. As noted before, the recuperator cylinders are
four in number and they are 1.6 meters in length. There are two
columns of springs in each cylinder, the mean diameter of the outside

CRADLE RECOIL CVUNDERS AND RECUPERATORS OF THE 17 CM, BATTERY

806

spring being 17 centimeters, diameter of wire 2.4 centimeters, and
the pitch 5 centimeters. The mean diameter of the inside spring
is 11 centimeters, the diameter of the wire 1.5 centimeters, and the
pitch 3 centimeters. Tension rods connect the crosshead at the
front of each spring column with the recoil lug.

837. Elevating Mechanism. — ^The elevating mechanism includes
a circular rack bolted to the side of the gun near the breech. The
pinion meshing with this rack is driven by an electric motor carried
on the part of the carriage below the floor.

838. Traversing Mechanism. — ^A complete circular rack is
attached to the base ring. The traversing motor is carried on the
section of the top carriage which extends below the deck and connects
with the traversing rack through two sets of bevel gears and one spur
gear. The entire original gun and turret mechanism, without any
modifications, were installed on the concrete emplacement as shown
on plate 530.

839. Carriage. — ^The one detail of the carriage which seems of
interest to describe is the traversing ball bearing. A portion of the
light shield protecting the bearing has been torn away approximately
at the center of the turret and almost above the long-exposed anchor
bolt. It was found on removing this shield that the carriage is
provided with a double ball path, the diameter of the outer path
being 3.2 meters and the inner path 2.8 meters. The balls in the
outside bearing are about 5 centimeters in diameter and in the inside
bearing 7.5 centimeters.

840. Emplacement. — ^These guns, all placed in the shore dunc^ at
Zeebrugge, are easily visible from the sea. The concrete emplace-
ment shown on plate 530 is about level with the top of the dune. A
railway line, evidently constructed by the Germans, runs along the
top of the dune just in front of the gun. The thickness of the concrete
wall at the rear is about 1.5 meters. This wall increased in thickness
on the sides to several meters, flaring off to the right and left at the
front. There was a door leading into the operating room under the
turret just under the two short anchor bolts seen in the center of
the picture.

841. Ammunition Supply System. — Ammunition was supplied
to the gun through the door just mentioned in the emplacement
and was hoisted by the usual type of electrical turret hoist. Appar-
ently there was no provision for supplying ammunition in any other
way.

842. PROTECTioii, — All of the guns were protected as shown in
plate 530. This turret was made up of 10-centimeter armor.

843. Destruction. — Apparently the usual scheme of destroying
the gun was not employed in these cases. Instead, by some method
they detonated a number of projectiles inside the turret and in the
operating room below. All but one of the emplacements was de-

809

stroyed as badly as the one in the plate. In each case the roof of
the turret was blown ofiF. The explosions which destroyed the
emplacements do not seem to have destroyed the turret mechanism,
as one would have expected. In: the case of the gun shown there
were about half a dozen unexploded projectiles in the turret and
twice that number in the operating room below. All of these pro-
jectiles were of the design shown on plate 532.

IS-CENTIMETER GUN, BATTERY IRENE.

844. Gun. — ^All of the guns of the Battery Irene, plate 533, are of
the model 1900, and the gun inspected is model 1900, No. 478-L.
The weight is 4,861 kilograms, the total length 6 meters, and the
length of the tube to the face of the breechblock 5.57 meters. The
nimiber of grooves is 44 and the twist of the rifling is to the right 1
centimeter in 10 centimeters. The diameter of the powder chamber
is 18 centimeters. The breechblock is of the standard Bjrupp sUding
wedge type.

845. Cradle. — The cradle, which is not unusual in design, is shown
on plate 534. The trunnions are provided with an antifriction device
of the design shown on plate 535. Two lugs are cast on the bottom of
the cradle near the rear to which the recoil piston is attached by
means of a pin. Two other lugs are provided to which the spring
recuperator cylinders are bolted.

846. Recoil Mechanism. — ^Attention is called to the rather
unique design of the recoil mechanism. This is the only case ob-
served in which the cylinder is carried in the breech lug, the piston
being attached to the cradle by means of a pin passing through the
two lugs just mentioned. The recuperator cylinders are two in
number. Two 3-centimeter tension rods connect the breech lug
with the crosshead at the forward end of the spring cylinders. These
recuperator cylinders are faced off on the inside at the rear to serve as
a guide for the breech lug to prevent rotation of the gun.

847. Elevating Mechanism, Traversing Mechanism, Carriage
Emplacement, Ammunition Supply System, Protection. — ^There
are no features of any of these items that are worthy of description.

848. On the inside of the armor of another carriage of identical
design, but of the Battery Kaiserin, near Blankenburg, there was
printed firing data, as shown on plate 536.

CONCLUSIONS.

849. Gun. — ^Most of the guns inspected are about 42 calibers in
length, measuring from the face of the breechblock, or about 45
calibers in total length. All guns are provided with the standard
Krupp type of sliding wedge breechblock. In aU cases, except with
the 28 centimeter mortars, which are model 1892, the twist of the
rifling is uniform to the right 1 centimeter in 10 centimeters. There

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FIRING DATA PAINTED ON THE SHIELDS OF THE 15 CM. GERMAN GUNS.

815

are no guns older than 1904. Quite a number of the guns are as late
as 1916. If the data given in the Bulletin de Renseignement d'Artil-
lerie of January-February, 1919, can be accepted, it is certain that the
Germans were securing ranges from these guns at ordinary muzzle
velocity far in excess of the ranges that we are securing from our guns.
This is probably through the improvement in their projectile design.

850. Cradles. — ^All cradles constructed may be termed smooth
Cylinders, and the maximum thickness of the walls is 10 centimeters.
The cradles of the larger gims are provided with bronze liners about
6 millimeters thick and 1 meter long, at both forward and rear ends.
In all cases, the cradles are provided with the simplest types of
brackets for the attaching of the recuperator and recoil cylinders.

851. Provision to Prevent Rotation of the Gun. — ^AU breech
lugs are fastened to the gun by the interrupted ring method. All
lugs are so shaped as to bear either between two recuperator cylinders
or on two sides of a single recuperator cylinder to prevent rotation of
the gun. There is no evidence in any case of the use of the spline,
typical in American desiga, for the prevention of rotation of the gun.

852. Hydraulic Buffers. — In most cases, two hydraulic buflFers
are provided. Apparently, there is no fixed policy of balancing these
since, in many cases, the two cylinders are located on the bottom of
the cradle. In some cases, the hydraulic cylinders are provided with
extensions on the forward end which are evidently counterrecoil
buffers. In a number of other cases, no such extensions are visible.

853. Recuperators. — ^The designers seem to have favored the
combined air-spring recuperators for the heayy guns. There is no
attempt at balancing them, and the number of cylinders varies from
one to four. All of the 380 and 305 millimeter guns are provided
with only one recuperator cylinder each. As noted under the heading
of '* Rotation of gun,*' in every case the recuperator cylinders are used
as guides for the extension of the breech lug to prevent rotation of
the gun.

854. Gun Carriage — ^Traversing Mechanism. — In all cases, the
heavy gim carriages are constructed entirely of structural steel, and
with the exception of the 28-centimeter mortar carriages, are of the
front pintle type. The pintle bearings in aU cases are ball bearing
and there is only one case of actual provision for direct contact
between the racer and base ring for transmission of the horizontal
force of recoil into the emplacement. The rear of the carriages is
carried on heavy rollers (two to four in number, 10 to 20 centimeters
across the face and 0.60 to 1 meter in diameter) running on circular
tracks set in the concrete emplacement. In some cases (38-centi-
meter guns) the traversing pinion meshes with a rack attached to the
roller path. In other cases (380 and 305 milhmeter guns) the
traversing pinion meshes with gears bolted to the face of the rollerp

181768—21 52

816

855. Elevating Mechanism. — The variations in the design of the
elevating mechanism found on German coast carriages as well as
railway carriages is very striking. On the 38-centimeter railway
mount found at Brussels, and the 305-miHimeter carriages of the
Battery Kaiser Wilhelm IT, there are double straight racks, but
the dimensions and designs differ quite radically. With the 38-
centimeter guns of the Batteries Pommern and Deutschland, there
are double-telescoping screws. On the Battery Tirpitz there is a
double-curved rack attached to the bottom of the cradle. On the
Battery Groden, 28-centimeter mortars and the guns of several other
batteries, there are single-curved racks attached to the bottom of
the cradle. On the Battery Goebcn, 17-centimetcr guns, circular
racks are attached to the sides of the cradles.

856. Ammunition Supply System. — ^In all cases, the ammunition
is conveyed from the storehouses into the gun by hand. The shot
trucks are all of extremely simple design, and the projectiles in all
cases are rammed by hand.

857. Ammunition Storage. — With all of the heavier batteries, the
layout of the ammunition storehouses is as shown on plates 557 and
558. J n each case, the storehouses are designed to house projectiles
and powder for the main guns as well as ammunition for the anti-
aircraft guns provided for the protection of each of the big batteries.

858. Protection. — ^Jt is very significant that there is no evidence
of a policy of providing heavy protection for these large caliber and
valuable guns. Apparently, all of the guns which are provided with
the 6-centimeter flat plate armor have been removed from other
coast fortifications where they had been previously provided with
the same armor. Nearly all of the guns were elaborately camou-
flaged, but air photographs taken in 1916, 1917, and 1918 show quite
clearly the positions of all of the guns, ammunition storehouses,
approach tracks, etc.

859. Jn spite of the lack of protection and the clear evidence of the
position of the batteries from air photographs, there is no evi-
dence that any of the guns was ever damaged, or even hit, by shell
fire or by bombs from airplanes. It is understood that the coast
fortifications were shelled constantly by the heavy guns of the
Allies' monitors. The positions of the guns were known, but either
the smoke screens that were at once put up by the Germans were
unusually effective, or the systems of fire control that were employed
were defective. The reasons for the failure of the aviators to obtain
any satisfactory results are not certain. They dropped msLXiy
bombs in the vicinity of the various battbries. H is probable that
the accuracy of the antiaircraft guns provided with all of the large
batteries was such as to compel the aviators to operate at a very
great height.

BIBLIOGRAPHY.

1. ''Official Records of the War of the Rebellion/' Vol. XI, part 2, pp. 574-576, 61C,

615, 664, 717-718; Congressional Library*.

2. "Battles and Leaders of the Civil War," Vol. II, pp. 373-374; Congressional

Library.

3. "Moblizable Fortifications," Gen. Joseph L. Brent, pp. 57; Congressional Library;

published by Williams & Wilkins Co., Baltimore.

4. "War Photographs Taken on the Battlefields During the Civil War of the United

States," pp. 95-96; Congressional Library.

5. "Professional Papers, Corps of Engineers, No. 14, Siege Artillery in the Campaign

Against Richmond," pp. 23; Office Chief of Engineers; also Library of the War
College.

6. "Revue de T Artillerie, " Vol. VII, 1876, pp. 8.

7. "Proceedings of the Institute of Civil Engineers," Nov. 22, 1881.

8. "Minutes of the Proceedings of the Royal Artillery Institute," Vol. XV, 1888.

9. "Revue de T Artillerie, " Vol. LX, 1894, pp. 34.

10. "Revue del' Artillerie."

11. "Hong Kong Daily Press," June 13, 1900.

12. "Engineer," Sept. 3, 1915; Congressional Library.

13. Ordnance Handbook No. 1783; complete drawings, Office Chief of Ordnance.

14. Gun and gun carriage drawings, Navy Bureau of Ordnance; railway car drawings,

Office Chief of Ordnance.

15. Army gun and carriage drawings. Office Chief of Ordnance; Ordnance Handbook

No. 1816.

16. Navy gun drawings, Navy Bureau of Ordnance.

17. Army gun and carriage drawings, Office Chief of Ordnance; Navy gun drawings.

Navy Bureau of Ordnance.

18. Mortar and carriage drawings, Office Chief of Ordnance.

19. Army gun and carriage drawings, Office Chief of Ordnance; Navy gun drawings,

Navy Bureau of Ordnance; Ordnance Handbook No. 2020.

20. Gun and carriage drawings, Office Chief of Ordnance; Ordnance Handbook No.

1985.

21. Howitzer and carriage drawings, Office Chief of Ordnance.

22. Gun and carriage drawings. Office Chief of Ordnance; test firing records, Fort

Monroe.

23. Gun and carriage dra^\'ing9, Navy Bureau of Ordnance; copies of same, Office

Chief of Ordnance; Navy Handbook No. 25; five such mounts operated in
France under Admiral Plunkett; all mounts now in posseasion of the Army.

24. Gun and carriage drawings, Navy Bureau of Ordnance; copies of same. Office

Chief of Ordnance; both mounts? now in possesvsion of Army.

25. Design only, gun drawings, Navy Bureau of Ordnance; copies, Office Chief of

Ordnance; carriage drawing, Office Chief of Ordnance.

26. Design only, gun drawings. Navy Bureau of Ordnance; copies, Office Chief of

Ordnance; carriage drawings, Office Chief of Ordnance.

27. Howitzer and carriage drawings, Office (^hief of Ordnance.

(81 7)

818

28. Howitzer and carriage drawings, Office Chief of Ordnance.

29. Study only, Preliminary Studies, Calculations, etc.. Office Chief of Ordnance.

30. One mou^t at Aberdeen and one at Fort Monroe; no drawings available; '* Super-

Heavy Flat Trajectory Guns " (S. S. 769); translation by General Staff, A. E. F.,
Library, War College; Library, Fort Monroe; A. E. F., G. H. Q., files.

31. One mount at Fort Monroe; no drawings available; "Super-Heavy Flat Trajectory

Guns."

32. One mount at Aberdeen; no drawings available; ''Super-Heavy Flat Trajectory

Guns."

33. No mounts captured by any army; photograph secured from the Krupp Co.; no

drawings available; ''Super-Heavy Flat Trajectory Guns."

34. One mount and ammunition car captured by British Army, now in England;

"Super-Heavy Flat Trajectory Guns."

35. One mount captured by Belgian Army, now in Belgium, probably Antwerp;

"Super-Heavy Flat Trajectory Guns."

36. "Manual of the Course for Student Officers," original and translation; Library,

Fort Monroe; also A. E. F., G. H. Q. files.

37. See also "Camouflage for Railway Mounts," Journal of the United States

Artillery, May, 1919.

38. Original recommendation with reference to shop equipment submitted by Maj.

Ralph Plumb, commanding officer of the R. A. R. repair shop, Hausaimont,
France.

39. War Department Document No. 967.

40. See also Report of Heavy Artillery Board, A. E. F., dated Aug. 16, 1918, on

"Equipment for the 12-inch Batignolles Railway Mount," signed H. S. Miller,
Lt. Cpl. C. A. C; Library, Fort Monroe.

41. A more complete treatment on Clearance Diagrams, with maps and diagrams of

all of the principal American railways has been made up by the Railway and
Seacoast Carriage Section, Artillery Division of the Ordnance Department;
copies on file. Library, Fort Monroe; Office Chief of Coast Artillery.

42. See "Table of United States Army Cannon and Projectiles," Ordnance Pamphlet

No. 1676; "Elements of United States Naval Guns," Navy Bureau of Ordnance;
"Super-Heavy Flat Trajectory Guns" (German; siee reference 30 above.)

43. See also " L'lllustration " (French) for Jan. 4, 1919. See "Genie Civil " (French)

for Apr. 20, 1918, for reconstitution and measurement of projectiles. Analyses
of projectile made in laboratory of Andre Citroen, Paris. Fragments of pro>
jectiles in Museum of Municipal Laboratory in Paris.

44. See also "Journal of the United States Artillery," June, July, August and De-

cember, 1919.

45. See also "L 'Illustration" (French) for Jan. 4, 1919.

INDEX.

A.

Paragraph.

Abbott, Brig. Gen. Henry L., Civil War 4

Access tracks ■ 546

Accuracy life of guns 54

Action, administratioif of original orders 492

Action, orders for 490

Action, preparation of positions for 492

Adjustment of track 527

Advance of forcing cone 612

Aerial observation 593

Aiming point, finite 577

Aiming point, infinite 578

Air density, corrections for , 589

Ammunition car, standard, S-inch American gun 121

Ammunition, German long range gun 732

Anmiunition storage. Belgian coast fortifications, conclusions on 857

Ammunition supply system:

4.7-inch American howitzer mount 99

7-inch American Navy gun mount 109

8-inch American gun moimt 121

10-inch American gun mount 143

12-inch American mortar mount 160

12-inch 20-caliber American howitzer mount .^ 202

12-inch 35-caliber American gun mount 176

12-inch 50-caliber American gun mount 191

14-inch 45-caliber American gun mount, model E 219

14-inch American gun mount, model 1918 264

14-inch American gun mount, model 1919 274

14-inch 50-caliber American Navy gun mount, Mark 1 233

14-inch ^-caliber American Navy gun mount, Mark 11 250

16-inch American howitzer mount, model E 286

16-inch American howitzer mount, model 1918 300

16-inch 50-caliber American gun mount 317

15-centimeter gun, Battery Irene 847

170-millimeter German gun mount 331

17-centimeter gun, Battery Goeben 841

210-millimeter German gun mount 346

240-millimeter German howitzer mount 360

280-millimeter German gun mount 376

28-centimeter gun, Battery Preussen 815

28-centimeter gun. Battery Tirpitz 824

28-centimeter mortar, Battery Groden 832

305-millimeter gun. Battery Kaiser Wilhelm II 805

(819)

820

Ammunition supply system — Continued. Paragraph.

380-millimeter German gun mount 397-399

38-centimeter gun, Battery Deutschland 794

38-centimet«r gun, Battery Pommern 780

Belgian coa^t fortifications, conclusions on 856

German long-range gun 731

Relative merits of design 449-451

Anchorage:

4.7-inch American- howitzer mount 94

7-inch American Navy gun mount 107

8-inch American gun mount 118

10-inch American gun mount 141

12-inch American mortar mount 158

12-inch 20-caliber American howitzer mount 200

12-inch 35-caliber American gun mount 173

12-inch 50-caliber American gun mount 189

14-inch 45-caliber American gun mount, model E 214-217

14-inch American gun mount, model 1918 262

14-inch American gun mount, model 1919 272

14-inch 50-c^iber American Navy gun mount, Mark 1 231

14-inch 50-caliber American Navy gun mount, Mark II 248

16-inch American howitzer mount, model E 283-284

16-inch Americ*an howitzer, model 1918 298

16-inch American gun mount 31 5

170-millimefer German gun mount 326

210-millimeter German gun mount 344

240-millimeter German howitzer mount 358

280-millimeter German gun mount 374

380-millimeter German gun mount 390

Clasksification according to 34

Classification of artillery according to 60

Discussion of methods of 38

For rolling type mount 35

For sliding type mounts 36

German long-range gun 725

Ground platform 60

Mounts requiring none 60

Relative merits of design 441-446

Scheme of, without platform 35

Track platform 36, 60

Antifriction bearingp:

10-inoh American gun mount 137

12-inch American mortar mount 154

12-inch, 20-caliber American howitzer mount 196

12-inch, 35-caliber American gun mount 169

12-inch, 50-caliber American gun mount 184

14-inch, 45-caliber American gun mount, model E 209

1 6-inch American howitzer mount, model 1918 294

Belgian coast guns, conclusions on 852

Armament officer, Railway Artillery Reserve 645

Armor:

15-centimeter gun, Battery Irene 847

17-centimeter gun. Battery Goeben 842

28-centimeter gun, Battery Preussen 816

821

«

Armor — Continued. Paragraph.

28-centimeter gun, Battery Tirpitz. .• 825

305- millimeter gun, Battery Kaiser Wilhelm II 808

38-centimeter gun, Battery Pommem 782

38-centimeter gun, Battery Deutschland 795

Belgian coaet guns, conclusions on : 858

"Artillery C" 408

Assembly of railway artillery 594-599

Assembly of railway artillery, personnel and equipment for 599

Assignment of calibers according to resistance of targets 51

Assignment of mounts according to time for emplacement 53

Assignment of mounts according to range 53

Assignment of mounts, ))asLs of 50

Asfcignment of mounts on basis of wear 55

Atmospheric saturation 589

A^uto-frett-age 407

\utomatic supply of equipment 655

Automatic supply, Railway Artillery Reserve 637

Axle loads 687

Ballast : 538

BallaBtic wind 590

Ballasting 527

Base ring, 14-inch, 45-caliber American gun mount, model E 214-217

Batignolles mounts:

Platforms required 37

Pre\dous placing of platform 60

Battery epi 541

Battles and leaders of the Civil War 2

Beams, firing 536

Belgian coast defenses , 756-859

Belgian coast defenses, geographical plan of 767-772

Belgian coast defenses, scope of service 772

Belgian coast defense gun, 38-centimeter, Battery Pommern 773-783

Blacksmith tools 658

Bombardment of Paris, details of 698-708

Bombardment of Paris, effect of 699

Bombardment of Paris, first impressions 690

Brady, \Vm. P. (Civil War pictures) 3

Brakes, muzzle 410

Breakage of railway mounts ^ 618

Breach mechanisms:

4.7-inch American howitzer 88

7-inch American Navy gun 101

8-inch American gun 112

10-inch American gun 135

12-inch American mortar 149

12-inch 20-caliber American howitzer 194

12-inch, 35-caliber American gun 167

12-inch, 50-caliber American gun 182

14-inch, 45-caliber American gun 207

14-inch, 50-caliber A merican Navy gun, Mark 1 225

14-inch, 50-caliber American Navy gun, Mark II 240

822

Breech mechaniBms — Continued. Pan^raph.

14-inch, 50-caliber American gun, modei 1918 256

14-inch, 50-caliber American gun 266

16-inch American howitzer, model 1918 277

16-inch American howitzer 292

16-inch, 50-caliber American gun 309

15-centimeter gun, Battery Irene 844

170-millimeter German gun 319

17-centimeter gun. Battery Goeben 834

210-millimeter German gun 337

240-millimeter German howitzer 352

280-millimeter German gun 368

28-<^ntimeter gun, Battery Tirpitz • 817

305-millimeter gun, Battery Kaiser Wilhelm II 798

380-millimeter German gun 382

38-centimeter gun, Battery Pommern 774

38-centinieter gun. Battery Deutschland 784

Brent, (Jen. Joseph, Confederate Army 2

Buffer stops '. 532

Bursting of tubes 611

Calibers:

Subdivisions of guns by 472

Study of relative efficiency of 740-755

Camouflage 497,502,545

Camouflage, 380-millimeter German gun mount 395

Camouflage, German long-range gun 729

Cannon, maintenance of 609

Capacity for delivering explosive, 14-inch, 50-caliber gun 72

Car body:

4.7-inch American howitzer mount 93

7-inch American Navy gun mount 106

8-inch American gun mount 117

10-inch American gun mount 140

12-inch American mortar mount 157

12-inch, 20-caliber American howitzer mount 199

12-inch, 35-caliber American gun mount. .: 172

' 12-inch, 50-caliber American gun mount 188

14-inch, 45-caliber American gun mount 213

14-inch, 50-caliber American gun mount, model 1918 261

14-inch, 50-caliber American gun mount, model 1919 271

14-inch, 50-caliber American Navy gun mount, Mark I ., 230

14-inch, 50-caliber American Navy gun mount, Mark II 247

16-inch American howitzer mount, model E 282

16-inch American howitzer mount, model 1918 297

16-inch American gun mount 314

170-millimeter German gun mount 325

210-millimeter German gun mount 343

240-millimeter German howitzer mount 357

280-millimeter Grerman gun mount 373

380-millimeter German gun mount 389

German long-range gun 724

Carpenter tools 658

823

Carriages: Paragraph.

10-inch American giin 139

15-centimeter gun, Battery Irene 847

17-centimeter gun, Battery Goeben 839

28-centimeter mortar, Battery Groden 830

28-centimeter gun, Battery Preuceen 812

28-centimeter gun, Battery Tirpitz 822

305-millimeter gun, Battery Kaiser Wilhelm II 804

38-centimeter gun, Battery Deutschland 792

38-centimeter gun. Battery Pommem 778

Barbette, 8-inch American gun 116

Belgian coast guns, conclusions on 854

Garriages, top or gun:

4.7-inch American howitzer 92

7-inch American Navy gun 105

10-inch American gun 140

12-inch American mortar 156

12-inch, 20-caliber American howitzer 198

12-inch, 35-caliber American gun 171

12-inch, 50-caliber American gun 187

14-inch, 45-caliber American gun 212

14-inch, 50-caliber American gun, model 1918 260

14-inch, 50-caliber American gun, model 1919 270

14-inch, 50-caliber American Navy gun, Mark L 229

14-inch, 50-caliber American Navy gun, Mark II 244

16-inch, American howitzer, model E 281

16-inch, American howitzer, model 1918 296

16-inch, American gun 313

170-millimeter German gun 324

210-millimeter German gun 342

240-millimeter German howitzer 356

280-millimeter German gun 372

28-centimeter mortar, Battery Groden 826

380-millimeter German gun 388

Car traversing mounts 60

Car traversing mounts, characteristics of 21

Center stakes 511

Circumstance, affuts de 23

Classification according to recoil systems 24

Classification of artillery according to range 60

Classified information 689

Coast defense:

Adaptation of railway artillery for 452-465

Belgian 756-859

Guns for 477

Qualification of railway artillery for 404M88

Requirements for 80

Targets .' 79

Use of railway artillery for 78

Composite diagrams:

A and B 676

French 677

824

Composite diagrams — Coi^tinued. Paragraph.

Method of using 672

United States 665

Combinations in design 466

Conclusions on:

Equipment 662

Guns 660

Maintenance 663

Mechanisms of Belgian coast defenses 849-859

Mounts 661

Shops 663

Construction:

Firing epi 537

Of artillery positions 496

Track 518

Coppering 612

Corrections, to range and deflection 588

Counter-battery :

Guns for 477

Use of railway artillery for 43-44

Counter-battery work:

Classification of artillery according to 60

Time available for em placing and removing batteries 59

Cradles: •

15-ceniimeter gun. Battery Irene 845

17-centimeter gun, Battery Goeben 835

28-centimeter gun, Battery Preussen 809

28-centimeter gun, Battery Tirpitz 818

305-millimeter gun, Battery Kaiser \N ilhehn II 798

38-centimeter gun. Battery Deutschland 786

38-centimeter gun. Battery Pommern 774

Belgian coast defense guns, conclusions on 850

Long-range German gun 718

Cradle recoil, classification according to. . : 25

Cradle rolling recoil, merits of 33

Crane equipment, special, 16-inch American gun 306

Criticism of railway mounts, basis of 82

Criticism, summary of basis of 86

Crossings, grade 531

Cut and fill, side slopes 516

Curves, clearances on 679-684

Curves, to lay out 573

D.

Deflectors, gas 410

Demerits:

7-inch American Navy gun mount : 1 10

8-inch American gun mount 130-131

10-inch American gun mount 147

12-inch American mortar mount 165

12-inch, 20-caliber American howitzer mount 205

12-inch, 35-caliber American gun mount 180

14-inch, 45-calibcr American gun mount 223

14-inch, 50-caliber American Navy gun mount, Mark 1 237

14-inch, 50-caliber American Navy gun mount, Mark^II 254

825

Demerita — Continued. Paragraph.

16-inch, American howitzer, model E 290

16-inch, American howitzer mount, model 1918 304

170-millimeter German gun mount 335

210-millimeter German gun mount /. 350

240-milHmeter German howitzer mount 364-365

280-millimeter German gun mount 380

380-millimeter German gun mount 403

Deployment of railway artillery 562

Depot supply of equipment 655

Depots of fuel 553

Design, combinations of, discussion of 466

Design details, relative merits of 405

Design of a mount for 10-inch, 50-caliber gun 84

Designs of long-range guns 737

Design, suggestion for superheavy guns 85

Destruction:

17-centimeter gun, Battery Goeben 832

38-centimeter gun, Battery Deutschland 785, 796

38-centimeter gun, Battery Pommern 783

Classification of artillery according to 60

Belgian coast guns, conclusions on 859

Guns for 477

Mine galleries 52

Use of railway artillery for 42

Deviation Board, Pirie 592

Deviation Board, Unkle 592

Difficulties involved in service:

8-inch American gun mount 123-128

10-inch American gun mount 145

12-inch American mortar mount 162-163

12-inch, 35-caliber American gun mount 178

14-inch, 45-caliber American gun mount, model E 221

14-inch, 50-caliber American Navy gun mount, Mark 1 235

14-inch, 50-caliber American Navy gun mount, Mark II 252

16-inch American howitzer, model E 288

16-inch American howitzer mount, model 1918 302

170 millimeter German gun mount 333

210 millimeter German gun mount 348

240 millimeter German howitzer mount 362

280 millimeter (lerman gun mount 378

380 millimeter German gun mount 401

Discussion, classification of mounts according to traverse 23

Discussion of design combinations 466

Dispersion :

German long range gun 70

I'nited States Navy 14-inch gun 72

Displacement of track, lateral, effect on accuracy of fire 586

Disposition of Railway Artillery 600

Distant bombardment:

Actual example of 48

Classification of artillery according to 60

Damage from 49

Use of railway artillery for 46

826

Paragraph.

Drainage, track 560

DreBBiiig the track 556

Drop bombs:

For interdiction service 74

General use of 75

E.

Earth work 514

Efficiency of different calibers, study of 740-755

Elevating mechanisms:

4. 7-inch American howitzer mount 90

7-inch American Navy gun mount 103

8-inch American gun mount 114

10-inch American gun mount 137

12-inch American mortar mount 160

12-inch, 20-caliber American howitzer mount 196

12-inch, 35-caliber American gun mount 169

12-inch, 50-caliber American gun mount 134

14-inch, 45 caliber American gun mount, model E 209

14-inch, 50-caliber American gun mount, model 1918 258

14-inch, 50-caliber American gun mount, model 1919 268

14-inch, 50-caliber American Navy gun mount, Mark 1 227

14-inch, 50-caliber American Navy gun moimt, Mark II 242

16-inch American howitzer mount, model E 279

16-inch American howitzer mount, model 1918 294

16-inch American gun mount 311

15-centimeter gun, Battery Irene 847

170-millimeter German gun mount 321

17-centimeter gun. Battery Goeben 837

210-millimeter German gun mount 339

240-millimeter German howitzer mount 354

280-millimeter German gun mount 370

28-centimeter gun. Battery Preussen. ; 809

28-centimeter gun. Battery Tirpitz 820

28-centimeter mortar, Battery Groden 828

305-millimeter gun. Battery Kaiser Wilhelm II 802

380-millimeter German gun mount 386

38-centimeter gun. Battery Deutschland 788

38-centimeter gun. Battery Pommem 776 -

Belgian coast guns, conclusions on 855

German long range gun 721

Relative merits of design 413-423

Elevation stakes 512

Emplacement:

4.7-inch American howitzer mount 94

7-inch American Navy gun mount 107

8-inch American gun 118

10-inch American gun mount 141

12-inch American mortar mount 158

12-inch, 20-caliber American howitzer mount 200

12-inch, 35-caliber American gun mount 173

12-inch, 50-caliber American gun mount 189

14-inch, 45-caliber American gun mount, model E 214-217

827

Emplacement — Continued. Paragraph.

14-inch, 50-caliber American gun mount, model 1918 262

14-inch, 50-caliber American gun mount, model 1919 272

14-inch, 50-caliber American Navy gun mount, Mark 1 231

l&-inch American howitzer mount, model E 283

16-inch American howitzer mount, model 1918 298

15-centimeter gun, battery Irene 847

170-milUmeter German gun mount 327-329

17-centimeter gun, battery Goeben 840

210-nullimeter German gun mount 344

240-millimeter German howitzer mount 358

28-centimeter German gun, battery PreuBsen 813

280-millimeter German gun mount 374

28-centimeter gun, battery Tirpitz 823

28-centimeter mortar, battery Groden « 831

305-millimeter gun, battery Kaiser Wilhelm II 807

380-millimeter German gun mount 391-394

38-centimeter gun, battery Deutschland 793

38-centimeter gun, battery Pommem 779

Assignments of mounts according to time of 57

German long-range gun 725-726

Emplacing jacks:

4.7-inch American howitzer mount 96

7-inch American Navy gun mount 107

8-inch American gun mount 118

10-inch American gun mount 141

12-inch American mortar mount 158

12-inch, 20-caliber American howitzer mount 200

14-inch, 45-caliber American gun mount, model E 214-217

14-inch, 50-caliber American gun mount, model 1918 262

14-inch, 50-caliber American gun mount, model 1919 272

14-inch, 50-caliber American Navy gun mount, Mark 1 231

16-inch American howitzer mount, model 1918 298

210-millimeter German gun mount 344

240-millimeter German howitzer mount 358

280-millimeter German gun moimt 374

380-millimeter German gun mount 390

Emplacing wedges:

12-inch, 35-caliber American gun mount 174

170-millimeter German gun mount 326

210-millimeter German gun mount 344

240-millimeter German gun mount 358

280-millimeter German gun mount 374

Eolmer switch 529

Erosion 612

Epis:

Epis 534

Battery 541

Construction 537

Curve, first use with railway mount 4

Group 542

Limit 539

Specifications 540

828

Equipment: Paragraph.

Automatic supply ' 656

Depot supply 655

Disposition in action 493-494

For assembly of railway artillery 599

Shop, American 624

Fire control 658

Shop, French 623

Shop, recommended 625

Summary of conclusions on 662

Table of, 653-^58

Equivalent chaises, table of 54

Expansion and joints 520

Explosives:

Delivering capacity of 14-inch, 50-caliber gun 689

Weight of, in German long-range shell 70

F.

Field artillery, province of 64

Field of usefulness of railway artillery, graphic representation of 77

Fill, side slopes 516

Finite aiming point 577

Finite and infinite aiming point, application to railway artillery 579-581

Fire control data, preparation of 574-598

Fire control equipment 658

Firing beams : • 536

Firing epi 548

Firing epi, construction 537

Firing platform:

8-inch American gun mount 118

10-inch American gun mount 141

12-inch American mortar mount 158

12-inch 20-caliber American howitzer mount 200

12-inch 35-caliber American gun mount 173-174

12-inch 50-caliber American gun mount 189

14-inch 45-caliber American gun mount, model E 214-217

14-inch 50-caliber American gun mount, model 1918 262

14-inch 50-caliber American gun mount, model 1919 272

14-inch 50-caliber American Navy gun mount, Mark 1 231

16-inch American howitzer mount, model 1918 298

16-inch American howitzer mount, model E 283

170-millimeter German gun mount 329

210-millimeter German gun mount 344

240-millimeter German howitzer mount 358

280-millimeter German gun mount 374

380-raillimeter German gun mount 390

Basis of criticism of mounts 82

('laasification of mounte according to 83

For heavv mounts 84

German long range gun 725

Suggestion for medium heavy caliber guns 84

Typos of 83

Forcing cone, advance of * 612

French railway diagrams 677

Fuel, depots of 553

829

G.

Paragraph.

Garages. 550

Garages, components 550

Gas deflectors 410

(leographic plan of Belgian coast defenses 767-772

German defenses on Belgian coast 756-859

Gen;nan long range gun, life of 70

German mounts, 210, 240, and 280 millimeters, platforms required 37

Goniometer, use of 575

Gorgas, Col., Confederate Army 2

Grade crossings 531

Ground platform, classification according to 37

Ground platform mounts 60

Group epi. 542

Gun book for railway artillery 607

Gums:

4.7-inch American howitzer 88

7-inch American Navy 101

8-inch American 112

10-inch American Army and Navy 13^

12-inch American mortar 149

12-inch 20-caliber American howitzer 194

12-inch 35-caliber American 167

12-inch 50-caliber American 182

14-inch 45-caliber American 207

14-inch 50-caliber American Navy 225, 240

14-inch 50-caliber American 256, 266

16-inch American howitzer, model 1918 277,292

16-inch 50 caliber American 309

15-centimeter, Battery Irene 844

170-millimeter 40-caliber German 319

17-centimeter, Battery Goeben 834

210-millimeter 45-caliber German naval 337

240- millimeter German howitzer 352

280-millimeter 40-caliber German 368

28-centimeter mortar, Battery Groden 826-833

28-centimeter, Battery Preuasen 809

28-centimeter, Battery Tirpitz 817

305-millimeter, Battery Kaiser Wilhelm II 797

380-millimeter German 382-384

38-centimeter, Battery Deutschland 784

38-centimeter, Battery Pommern 773

Belgian coast defenses, conclusions on 849

Conclusions as to calibers for servdoe 480

German long range 711-717

Railway, service required of 468

Reboring of 615

Rechambering of 614

Relative merits of design 40(>-410

Relining of 616

Retubing of 617

Subdivision by calibers 472

Subdivision for requirements of service 477

Summary of conclusions on 660

830

Gun carriages: Paragraph.

4.7-inch American howitzer mount 92

7-inch American naval gun mount 105

8-inch American gun moimt 116

10-inch American gtm mount 1S9

12-inch American mortar 156

12-inch 20-caliber American howitzer mount 198

12-inch 35-caliber American gun mount 171

12-inch 50-caliber American gun moimt 187

14-inch 45-caliber American gun mount, model E 212

14-inch 50-caliber American gun mount, model 1918 260

14-inch 50-caliber American gun mount, model 1919 270

14-inch 50-caliber American Navy gun mount, Mark 1 229

14-inch 50-caliber American Navy gun mount, Mark II 244

16-inch American howitzer mount, model £ 281

16-inch American howitzer mount, model 1918 296

16-inch American gun mount 313

170-millimeter German g-un mount 324

210-millimeter German gun mount 342

240-millimeter German howitzer mount 366

280-millimeter German gun mount 372

28-centimeter mortar. Battery Groden 826

380-millimeter German gun mount 388

Belgian coast guns, conclusions o^ 854

Gunner's quadrant, use of 575

H.

Handling of track materiel 561

Heavy artillery:

Development of, during the World War 67

Province of 65

History of installation of Belgian coast defenses 751-766

Howitzers, 4.7-inch American 88

I.

Inactive artillery, disposition of 495

Infinite aiming point 578

Inspection of railway artillery 602

Inspector:

Ammunition 650

Railway artillery 646-^9

Installation of Belgian coast defenses, history of 751-766

Interdiction:

Classification of artillery according to 60

Guns for 477

Use of drop bombs and heavy shells for 74

Use of railway artillery for 44

J.

Jacks, emplacing:

4.7-inch American howitzer moimt 96

7-inch American Navy gun mount 107

8-inch American gun mount 118

10-inch American gun mount 141

12-inch American n\prtar mount 158

831

Jacks, emplacing — Continued. Paragraph.

12-inch 20-caUber American howitzer mount 200

14-inch 4£^caliber American gun mount, model E 214-217

14-inch 50-caliber American gun mount, model 1918 262

14-inch 50-caliber American gun mount, model 1919 272

14-inch 50-caliber American Navy gun mount, Mark 1 231

16-inch American howitzer mount, model 1918 298

2107millimeter German gun mount 344

240-millimeter German howitzer mount 358

280-millim'eter German gun mount 374

380-millinieter German gun mount 390

Jacking beams:

10-inch American gun mount 141

12-inch 50-caliber American gun mount 189

14-inch 50-caliber American Navy gun mount, Mark 1 231

14-inch 50-caliber American gun mount, model 1918 262

14-inch 50-caliber American gun mount, model 1919 272

210-millimeter German gun mount 344

240-millimeter German gun mount 358

280-inillimeter German gun mqunt 374

Joints, rail 520

L.

Land warfare:

Procedure in preparing for action 489

Qualifications of railway artillery for 404-488"

Use of railway artillery for 40

Lateral displacement of track, effect on accuracy of fire 586

Laying in direction 576

Laying, instruments for 575

Lee, Gen. Robert E 2

Length of tracks 551

Life of German long-range gun 70

Limitations of railway artillery for land warfare 40

Long range gun:

Comparison of service with that of planes 71

Design of 709-712

German 690-739

Miscellaneous designs of • 737

Powder 738-739

M.

MacGruder, Maj. Gen., Confederate Army 2

Machinist tools 658

Maintenance:

7-inch American Navy gun 110

8-inch American gun 122

10-inch American gun 144

12-inch American mortar 161

12-inch 20-caliber American howitzer 203

12-inch 35-caliber American gun 177

12-ipch 50-caliber American gun 192

14-inch 45-caliber American gun, model E 220

14-inch 50-caliber American Navy gun, Mark 1 234

181768—21 63

832

Maintenance — Continued. 'Paragraph.

14-inch 50-caliber American Navy gun, Mark II ; 251

16-inch American howitzer, model E 287

16-inch American howitzer, model 1918 301

170-millimeter German gun 332

210-miliimeter German gun .- 347

240-millimeter German howitzer 361

280-millimeter German gun 377

380-millimeter German gun 400

Officer, railway artillery 651

Of cannon 609

Of railway artUlery 608

Organization for 619

Of tracks ^ 555

Kesponaibility for 619

Summary of conclueions on 663

Mallory, Honorable, Secretary of Navy, Confederate Union 2

Material, track 518

Mechanics, special, railway artillery 652

Merits:

7-inch American Navy gun mount 110

8-inch American gun mount 129

10-inch American gun mount ' 146

12-incli American mortar mount 164

12-inch, 20-caliber American howitzer mount 204

12-inch, 35-caliber American gun mount 179

14-inch, 45-caliber American gun mount, model E 222

14-incb , 50-caliber American Navy gun mount, Mark 1 236

14-inch, dO-caliber American Navy gun mount, Mark II 253

16-inch American howitzer mount, model E 289

16-inch American howitzer mount, model 1918 303

170 millimeter German gun mount 334

210-millimeter German gun mount 349

240-millimeter German howitzer mount 363

280-millimeter German gun mount 379

380-millimeter German gun mount 402

Middle ordinate of curves 679

Minor, Capt. George, Confederate Army 2

Mobilizable fortifications, by Gen. Brent 2

Moral effect, bombardment for 46

Mortar, 12-inch American 149

Mortar, 13-inch, ttvil War 4

Mounts:

Railway, conclusions as to types 484-488

Subdivisions, according to service 483

Summary of conclusions on 661

Muzzle brakes 410

N.

Napoleon III, Gen. Brent's conference with 2

Narrow-gauge equipment, 8-inch American railway mount 120

Navy 14-inch gun, dispersion of 72

Nontraversing mounts 60

Characteristics of 19-20

833
o.

Paragraph.

Observation, aerial 593

Official Records of the Rebellion 2

Ordnance officers, railway artillery:

Detailed functions of 632

Duties of ". 628-662

Qualifications of 632

Ordnance personnel, Railway Artillery Reserve 624

Ordnance supply officer, Railway Artillery Reserve 636

Outriggers:

7-inch American Navy gun 107

8-inch American gun 118

12-inch American mortar 158

12-inch, 20-caliber American howitzer 200

14-inch, 50-caliber American Navy gun mount, Mark 1 231

16-inch, American howitzer mount, model 1918 298

limitationB of use 84

Overhang on curves ^ 682

Panoramic sight, use of 575

Peigne, Gen., writings and inventions 9

Personnel for maintenance 620-621

Petersburg, alege of 3

Pirie deviation board 592

Platfonn car, 12-inch, 35-caliber American gun mount 173

Plotting board, artillpry 593

Pneumatic recuperators:

12-inch, 20-caliber American howitzer mount 196

12-inch, 35-caliber American gun mount 168

Powder for long-range guns 738-739

Projectiles, 38-centimeter gun, Battery Pommem 781

Protection:

15-centimeter gun, Battery Irene 847

17-centimeter gun, Battery Goeben 842

28-centimeter gun. Battery Preussen 816

28-centimeter gun, Battery Tirpitz 825

305-millimeter gun, Battery Kaiser Wilhehn II 808

38-centimeter gun, Battery Deutschland 795

38-centimeter gun, Battery Pommem '. 782

Belgian coast guns, conclusions on 858

Q.

Qualifications of railway artillery for land warfare and coast defense 404-488

!>•

Rail hooks, 4.7-inch American howitzer mount 95

Rails, replacing 558

Radial truck frames, 16-inch, American howitzer mount, model 1918 284

Rails, plan of placing 522

834

Railway artUlery : Paragraph.

All round fire 8

Armament officer 645

Assembly of 5W-599

Character and extent of development to present date 14

Glaasification according to chief factors in design 16

Coast defenses in Denmark 9

Confederate Army 2

Deployment of 662

Disposition of i 600

Economic calibers of 77

(Engineer, 1915) 4.7-inch and 6-inch guns 13

Experiments by Krupp and Skoda 8

First general use 9

For defense of Rhone Valley 9

For extreme ranges '. 75

French 305-millimeter gun 12

.German 42-centimeter railway mortars 12

Graphic representation«of field service of 62

Inspection of 602, 648

Inspector 646-649

Limit of 68

Limit of development to 1914 11

Maintenance of 608

Maintenance officer 651

Nations that have constructed 81

Necessity for speed in installation 58

(Proceedings Institute Civil Engineers, 1881) 6

(Proceedings Royal Artillery Institute, 1888) 7

Province of 65

Relation to other types 61

Reserve, Ordnance personnel 634

(Revue d'Artillerie, 1876) 5

(Revue d'Artillerie, 1894) 8

St. Chamond company 9

Scheme of fortifying inland cities, Paris, etc 2

Service record for gun book 607

South African war 10

Special mechanics 652

Upper limit 69

Use for coast defense 78

Railway battery, Civil War (caliber of gun unknown) 3

Railway battery, Confederate 2

Railway car body:

4.7-inch American howitzer mount 93

7-inch America^ Navy gun mount 106

8-inch American gun mount 117

10-inch American gun mount 140

12-inch American mortar 157

12-inch, 20-caliber American howitzer mount 199

12-inch, 35-caliber American gun mount 172

12-inch, 50-caliber American gun mount 188

14-inch, 45-caliber American gun mount, model E 213

14-inch, 50-caliber American gun mount, model 1918 261

835

Railway car body — Continued. Paragraph.

14-inch 50-caliber American gun mount, model 1919 271

14-inch 50-caliber American Navy gun mount, Mark 1 230

14-inch 50-caliber American Navy gun mount, Mark II 247

16-inch American howitzer mount, model E 282

16-inch American howitzer mount, model 1918 297

16-inch American gun mount. : 314

170-millimeter German gun mount 325

210-millimeter German gun mount 343

240-millimeter German howitzer mount 357

280-millimeter German gun mount 373

3S0-millimeter German gun mount 389

German long-range gun 724

Relative merits of design 436-440

Railway clearances 6C4-668

Railway carriage, 40-pounder gun 7

Railway guns, service required of 468

Railway mounts:

4.7-inch American howitzer 87-99

7-inch American Navy gun -. 100 -110

8-inch American gun 111-131

10-inch American gun 132-147

12-inch American mortar ^ 148-165

12-inch 20-caliber American howitzer '. 193-205

12-inch 35-caliber American gun 166-180

12-inch 50-caliber American gun 181-192

14-inch 45-caliber American gun mount, model E 206-224

14-inch 50-caliber American sliding type gun mount, model 1918 255-264

14-inch 50-caliber American sliding type gun mount, model 1919 265-274

14-inch American Navy gun, Mark 1 224-238

14-inch American Navy gun, Mark II 239-254

16-inch American howitzer, model E 275-290

16-inch American howitzer, model 1918 291-304

16-inch American gun 305-317

170-millimet«r, 40-caliber German gun 318-335

210-miUimeter, 45-caliber German gun 336-350

240-miUimeter German howitzer 366

280 -millimeter German gun , 367-380

380-millimeter German gun 381-403

Batignolles type for 12-inch American gun 166-180

Sliding type, development of 132-134

Wear and breakage of 618

Raising the track 556

Range^ assignment of railway mounts according to 53

Range, quadrant, use of 575

Reboring 615

Rechambering 614

Recoil :

(Cradle, cla^fication according to 25

Cradle, rolling 29

Cradle, rolling, merits of 33

Cradle, sliding 29

Combinations of 29

Discussion of relative merits of different systems 30-33

181768—21 54

836

Recoil — (/ontinued. Paragraph.

Rolling, clafisification according to 28

Sliding, classification according to 27

Sliding, merits of t 32

Systems, classification according to 24

Top carriage, classification according to 26

Top carriage, merits of 31

Top carriage, sliding 29

Recoil mechanisms:

4.7-inch American howitzer mount 89

7-inch American Navy gun mount 102

8-inch American gun mount 113

10-inch American gun mount 136

12-inch American mortar mount 150

12-inch 20-caHber American howitzer mount 195

12-inch 35-caliber American gun mount : 168

12-inch 50-caliber American gun mount 183

14-inch 45-caliber American gun mount, model E 208

14-inch 50-oaliber American gun mount, model 1918 257

14-inch 50-caUber American gun mount, model 1919 267

14-inch 50-caliber American Navy gun mount, Mark 1 226

14-inch, 50 caliber American Navy gim moimt, Mark II 241

16-inch American howitzer mount, model E 278

16-inch American howitzer moimt, model 1918 293

16-inch, 50-caliber American gun mount 310

15-centimeter gun, Battery Irene 846

170-millimeter German gun mount 320

17-centimeter gun. Battery Goeben 836

210-millimeter German gun mount 338

240-millimeter German howitzer mount 353

280-millimeter German gun mount 369

28-centimeter mortar. Battery Groden 827

28-centimeter gun, Battery Preussen 809

28-centimeter gun. Battery Tirpitz 819

305-millimeter gun, Battery Kaiser Wilhebn II 799-801

380-millimeter German gun moimt 385

38-centimeter gun, Battery Deutschland 787

38-centimeter gun, Battery Pommern 775

Belgian coast guns, conclusions on 852-853

German long-range gim 719

Relative merits of design 411-412

Requirements for coast defense 80

Requirements of good tracks .' 555

Resistance of targets, assignments of calibers according to 51

Retubing 617

Reversing triangles 533

Richmond, campaign against, use of railway artillery 4

Rifled projectiles 408

Rolling recoil railway mount, first use 4

Rolling recoil railway mount, second use 5

Recuperators, Belgian coast guns, conclusions on 853

Relative efficiency of different calibers 740-755

Relining 616

Repair car 626

837

Paragraph.

Repair facilities, line 626

Repair of shell cut 569

Replacing rails 558

Replacing ties ' 557

S.

Saturation, atmospheric 589

Scope of service of Belgian coast defenses 772

Scope of utility of railway artillery 39-80

Service, subdivision of guns according to 4 477

Service record of railway mounts, form for 607

Service required of railway guns 468

Seven Days' Battles 2

Shops: *

'American equipment of 624

French equipment of 623

Location of 622

Sunmiary of conclusions on 663

Shop equipment:

American 624

French 623

Recommended 625

Side slopes of cut and fill 516

Sliding mounts, method of laying for direction 582-585

Sliding mounts, previous placing of platform 60

Sliding recoil:

Classification according to 27

Merits of '. 32

Mounts, special type ! 60

Slip friction device, 8-inch American gun 116

Soisaons, offensive against 52

Spare parts 627, 655

Spacitications of standard track 514

Splines, Belgian coast guns, conclusions on ' 861

Spread of rails on curves 684

St. diamond mounts, platforms required 37

Stakes:

Center , 511

Elevation 512

Stops, buffer ^ 532

Storage, ammunition, Belgian coast guns, conclusions on 857

Super-elevation 519

Super-elevation of outer rails on curves 683

Supply officer, Railway Artillery Reserve 636

Supply system, ammunition:

4.7-inch American howitzer mount 99

7-inch American Navy gun mount 109

8-inch American gun mount 121

10-inch American gun mount 143

12-inch American mortar mount 160

12-inch 20-caliber American howitzer mount 202

12-inch 35-caliber American gun mount 176

12-inch 50-oaliber American gun mount 191

838

Supply system , ammunition — Continued. Paragraph.

14-inch 45-caliber American gun, model E 219

14-inch 50-caliber American gun mount, model 1918 264

14-inch 50-caliber American gun mount, model 1919 274

14-inch 50-caliber American Navy gun mount, Mark 1 233

14-inch 50-caliber American Navy gun mount, Mark II ... ^ 250

16-inch American howitzer mount, model E 286

16-inch American howitzer mount, model 1918 300

16-inch American gun mount 317

15-centimeter gim, Battery Irene 847

170-millimeter German gun mount 331

17-centimeter gun, Battery Goeben 841

210-millimeter German gun mount 346

240-millimeter German howitzer mount 360

280 millimeter Grerman gun mount ' 376

28-centimeter mortar. Battery Groden * 832

28-centimeter gun, Battery Preuasen 815

28-centimeter gun. Battery Tirpitz 824

305-millimeter gun, Battery Kaiser Wilhelm II 805

380-millimeter German gun mount 397-399

38-centimeter gun, Battery Deutschland 794

38-centimeter gun, Battery Pommem. . . : 781

Belgian coast guns, conclusious oui 856

German long range gun 731

Relative merits of design 449-451

Survey, preliminary 566

Swelling of tubes 611

Switch, Eolmer : 529

*

Tables of classified data 689

Table of equipment 653-658

Targets in coast defense 79

Targets in land warfare 491

Tamping ties 557

Temperature, corrections for 589

Thermometer readings, corrections for 589

Ties, plan of laying 521

Ties, replacing tamping 557

Tin-lead alloy 610

Tinner's tools 658

Tools and accessories 65^-658

Tools:

Blacksmith 658

Carpenter 658

Machinist 658

Tinners' 658

Track 658

Top carriage recoil, merits 31

Top carriages:

4.7-inch American howitzer mount 92

7-inch American Navy gun mount * 105

12-inch American mortar 156

12-inch, 20-caliber American howitzer mount 198

839

Top carriages — Continued. Paragraph.

12-inch, 50-caliber American gun mount .' 187

14-inch, 45-caliber American gun mount, model E 212

14-inch, 50-calibeT American gun mount, model 1918 260

14-inch, 50-caliber American gun mount, model 1919 270

14-inch, 50-caliber American Navy gun mount, Mark 1 229

14-inch, 50-caliber American Navy gun mount, Mark II 244

16-inch American howitzer mount, model £ 281

16-inch American howitzer mount, model 1918 296

16-inch American gun mount 313

170-millimeter German gun mount 324

210-millimeter German gun mount 342

240-millimeter German howit^ mount 356

28-centimeter mortar, Battery Groden 826

280-millimeter German gun mount 372

380-millimeter German gun mount 388

Top carriage recoil, classification according to 26

Top carriage traversing mounts 22

Top carriage traverse mounts 60

Tracks:

. Access 647

Adjustment 527

Construction 518

Drainage 560

Dressing and raising 556

Laying 524

Length 551

Material 518

Materiel, handling of 561

Kequirements of 555

Study of location of 504

Tools 658

Track platform mounts 60

Track work:

For heavy artillery 503

Specifications of v 514

Traverse:

Classification of artillery according to 60

Classification of mounts according to 18

Top carriage, classification according to 22

Traversing mechanisms:

4.7-inch American howitzer mount 91

7-inch American Navy gun mount 104

8-inch American gun mount 115

10-inch American gun mount 138

12-inch American mortar mount 155

12-inch, 20-caliber American howitzer mount 197

12-inch, 35-caliber American gun mount 170

12-inch, 50-caliber American gun mount 185

14-inch, 45-caliber American gun mount, model E 210-212

14-inch, 50-caliber American gun mount, model 1918 259

14-inch, 50-caliber American gun mount, model 1919 269

14-inch, 50-caliber American Navy gun mount, Mark 1 228

14-inch, 50-caliber American Navy gun mount, Mark II 243

DO NOT REMOVE

OR