Canon de 240 TR Mle 1903 sur affût-truck Mle 1914

Type	Railway gun Siege gun
Place of origin	France
Service history
Used by	France
Wars	World War I
Production history
Designer	Canet
Manufacturer	Gun: Schneider Carriage: St Chamond
Produced	1914
No. built	16^[1]
Specifications
Mass	Total: 47.8 t (47.0 long tons; 52.7 short tons) Gun: 17.8 t (17.5 long tons; 19.6 short tons)
Length	6.47 m (21 ft 3 in)
Barrel length	4.9 m (16 ft 1 in) L/20.6^[2]

Shell	Separate loading cased charge and projectile.
Shell weight	Cartridge: 53 lb (24 kg) Projectile: 140 kg (310 lb)
Caliber	240 mm (9.4 in)
Breech	Canet breech^[2]
Recoil	Hydro-gravity double recoil system
Elevation	+15° to +40°
Traverse	7° left/right
Muzzle velocity	526 m/s (1,730 ft/s)
Maximum firing range	17.3 km (10.7 mi)^[2]

The Canon de 240 TR Mle 1903 sur affût-truck Mle 1914 was a French railway gun and siege gun used by the French Army during World War I.

History

Before the First World War, the doctrine of the French Army was geared towards a war of rapid maneuver. Although the majority of combatants had heavy field artillery prior to the outbreak of the First World War, none had adequate numbers of heavy guns in service and once the Western Front stagnated and trench warfare set in the light field guns that the combatants went to war with were beginning to show their limitations when facing an enemy who was now dug into prepared positions. Indirect fire, interdiction and counter-battery fire emphasized the importance of long-range heavy artillery. Since aircraft of the period were not yet capable of carrying large diameter bombs the burden of delivering heavy firepower fell on the artillery. Two sources of heavy artillery suitable for conversion to field use were surplus coastal defense guns and naval guns.^[2]

However, a paradox faced artillery designers of the time; while large caliber naval guns were common, large caliber land weapons were not due to their weight, complexity, and lack of mobility. Large caliber field guns often required extensive site preparation because the guns had to be broken down into multiple loads light enough to be towed by a horse team or the few traction engines of the time and then reassembled before use. Building a new gun could address the problem of disassembling, transporting and reassembling a large gun, but it did not necessarily address how to convert existing heavy weapons to make them more mobile. Rail transport proved to be the most practical solution because the problems of heavy weight, lack of mobility and reduced setup time were addressed.^[2]

Design

Gun - The Canon de 240 TR Mle 1903 sur affût-truck Mle 1914 was designed by Canet and manufactured by Schneider. It started life as a coastal defense gun called the Canon de 240 TR Mle 1884-1903 sur affût G Mle 1903. It was a typical built-up gun of the period made from steel with a rifled inner tube and reinforced by layers of external tubes.^[3]

Breech - The gun fired separate loading cased charges and projectiles in which bags of propellant were placed inside a brass case to vary range and velocity. The shell casing together with the breech provided obturation to seal the breech during firing. Since the cases could be filled with bags of propellant ahead of time and loaded more quickly than guns using only bagged propellant it was considered a rapid-fire gun and the "TR" in its name stood for tir rapide or rapid-fire in English. The guns had a Canet rotating block breech that was a bit unusual as seen here on a Canet 155 mm (6.1 in) gun. The breech was semicircular in shape and was hinged at its center. When the breech was opened the projectile and casing were fed in and then the breech block was rotated 90° upward to seal the breech. When the gun fired the breech was opened, the case was ejected and the next round inserted.^[4]

Recoil System - The recoil system for the gun consisted of a U-shaped gun cradle which held the trunnioned barrel and a slightly inclined firing platform with a hydro-gravity recoil system. When the gun fired the hydraulic buffers on top and at the front of the cradle slowed the recoil of the cradle which slid up a set of inclined rails on the firing platform and then returned the gun to position by the combined action of the buffers and gravity.^[4]

Rail Carriage - Rather than being a true railway gun it was more of a multi-mode siege gun because the carriage built by St Chamond could be reconfigured to run on standard gauge rails, narrow gauge rails or fitted with road wheels like the Mortier de 293 Danois sur affut-truck modèle 1914 which was similar in construction and configuration. In the center of the carriage, there were the two standard gauge 4-wheeled railroad bogies that could be raised or lowered. There was also a narrow gauge 4-wheeled bogie at both ends that could also be raised and lowered. Lastly, jackscrews are provided on the car body for transferring from one set of trucks to the other. Road wheels could be substituted for the narrow-gauge trucks and the carriage could be towed by a traction engine. At the front of the carriage, there was a shear leg derrick that could be used to load and unload the gun for transport. The normal procedure was to transport the barrel and base on their own carriages on standard gauge rails until near the front and then transport both on narrow gauge rails or road wheels to the front. Site preparation consisted of creating a level piece of ground by laying a bed of stones and timbers then lowering the carriage onto the base plate. The base plate is prevented from moving by two anchors buried in front of the mount. The gun is then reassembled on the base plate and made ready for action.^[4]

Traverse and Elevation - The carriage employed a car traversing or berceau system where the car and trucks were placed on a base plate and could be traversed 7° left/right of the center line. The base plate is arranged with a pintle in front and the car has two rollers behind. At the rear of the rail carriage, there was a shell hoist and there was also a small cart which ran on rails to the breech for ammunition handling. The gun was loaded at +10° and could be elevated to a maximum of +40°.^[4]

Pros and Cons - Although adaptable the gun required considerable setup time.^[4]

World War I

The Canon de 240 TR Mle 1903 was assigned to units of the ALGP (artillerie lourde à grande puissance) during World War I. At first, they were organized in 4 groups of 2 batteries of 2 guns per battery. Later the guns were reorganized into 2 groups 1 with 3 batteries and 2 with 2 batteries of 3 guns with 1 spare.^[5] When the war ended there were 8 guns left in service.^[1]

Gallery

A schematic of the major gun components.
A barrel removed for transport on narrow gauge rails.
A carriage placed on road wheels without gun.
Reassembling a gun onsite.
An assembled gun on wide gauge rails.
The breech mechanism as used on a 155 mm gun.

References

^ ^a ^b "Une montée en puissance improvisée de l'A.L.G.P. de 1914 à 1918". basart.artillerie.asso.fr. Retrieved 2019-02-04.
^ ^a ^b ^c ^d ^e Hogg, Ian (2004). Allied artillery of World War One. Ramsbury: Crowood. pp. 129–134 & 218. ISBN 1861267126. OCLC 56655115.
^ "Canons côtiers de 24 C et 240 G et TR - FortiffSéré". www.fortiffsere.fr. Retrieved 2019-02-04.
^ ^a ^b ^c ^d ^e unknown (1921). Railway Artillery - A Report On The Characteristics Scope Of Utility, Etc. Ordnance Department Document No. 2034. pp. 59–63.
^ "Canon FISSA de 240 Mle 1903TR sur affût-truck Mle 1914 - Forum PAGES 14-18". forum.pages14-18.com. Retrieved 2019-02-04.

v t e French artillery of World War I
Anti-aircraft guns	Canon de 75 antiaérien mle 1913-1917
Coastal artillery	Canon de 100 mm Modèle 1891 Canon de 19 C modèle 1870/93 Canon de 19 C modèle 1875 Canon de 24 C modèle 1876 Canon de 240 L Mle 1884 Mortier de 270 mm modèle 1889
Field artillery	Canon de 75 modèle 1897 Canon de 75 modèle 1912 Schneider Canon de 75 modèle 1914 Schneider De Bange 90 mm cannon Obusier de 120 mm C modèle 1890 Obusier de 120 mm mle 15TR
Infantry guns	Canon d'Infanterie de 37 modèle 1916 TRP
Medium and heavy artillery	Canon de 105 mle 1913 Schneider Canon de 155 court modèle 1904 Rimailho Canon de 120 mm modèle 1878 Canon de 145 L modele 1916 Saint-Chamond Obusier de 155 mm C modèle 1881 Obusier de 155 mm C modèle 1890 Canon de 155 C modèle 1917 Schneider Canon de 155 C modèle 1915 St. Chamond Canon de 155 L modèle 1877/14 Schneider Canon de 155 L Modele 1917 Schneider Canon de 155 L modèle 1918 Schneider Canon de 155 mm GPF De Bange 155 mm cannon Canon de 220 L mle 1917 Mortier de 220 modèle 1915/1916 Schneider
Mortars	Cellerier Mortar Mortier de 58 T N°1 Mortier de 58 T N°1 bis Mortier de 58 mm type 2 Mortier de 75 modèle 1915 Schneider Mortier de 150 mm T Mle 1917 Fabry Mortier de 240 mm Mortier de 270 mm modèle 1885 Mortier de 270 mm modèle 1889
Mountain artillery	Canon de 65 M modele 1906 75 mm Schneider-Danglis 06/09 Canon Court de 105 M modele 1909 Schneider
Railway artillery	Canon de 120 L mle 1878 sur affût-truc Peigné-Canet-Schneider mle 1897 Canon de 140 sur affut-truc mle 1884 Obusier de 155 C mle 1881 sur affût-truc Peigné-Canet-Schneider mle 1897 Materiel de 155 sur affut-truc Schneider Canon de 164 modèle 1893/96 TAZ Canon de 19 C modèle 1875 Canon de 19 modèle 1870/93 TAZ Obusier de 200 "Pérou" sur affût-truck TAZ Schneider 24 cm Canon G modèle 1916 Canon de 240 L Mle 1884 Canon de 240 modèle 93/96 TAZ Canon de 274 modèle 93/96 Berceau Canon de 274 modèle 87/93 Glissement Canon de 305 modèle 93/96 TAZ Canon de 305 modèle 1893/96 à berceau Canon de 305 modèle 1893/96 à glissement Canon de 32 modèle 1870/81 à glissement Canon de 32 modèle 1870/84 à glissement Canon de 32 modèle 1870/93 à glissement Canon de 340 modèle 1893 à glissement Canon de 340 modèle 1912 à berceau Canon de 340 modèle 1912 à glissement Obusier de 370 modèle 1915 à berceau Canon de 370 modèle 75/79 Glissement Obusier de 400 Modèle 1915/1916 Obusier de 520 modèle 1916
Siege artillery	Obusier de 120 mm C modèle 1890 Canon de 120 mm modèle 1878 Obusier de 155 mm C modèle 1881 Obusier de 155 mm C modèle 1890 Mortier de 220 mm modèle 1880 Canon de 240 L Mle 1884 Canon de 240 TR Mle 1903 Mortier de 270 mm modèle 1885 Mortier de 270 mm modèle 1889 Mortier de 280 modèle 1914 Schneider Mortier de 293 Danois sur affut-truck modèle 1914 Mortier de 370 modèle 1914 Filloux
Self propelled artillery	Canon de 194 GPF Canon de 220mm L Mle1917 Schneider (FAHM) Mortier 280 mm TR de Schneider sur affût-chenilles St Chamond
Armoured vehicle guns	Puteaux 37 mm SA 18 Canon de 75 modèle 1897