The Mortier de 293 Danois sur affut-truck modèle 1914 was a French

railway gun A railway gun, also called a railroad gun, is a large artillery piece, often surplus naval artillery, mounted on, transported by, and fired from a specially designed railway wagon. Many countries have built railway guns, but the best-known are ...

and

siege gun Siege artillery (also siege guns or siege cannons) are heavy guns designed to bombard fortifications, cities, and other fixed targets. They are distinct from field artillery and are a class of siege weapon capable of firing heavy cannonballs o ...

used by the

French Army The French Army, officially known as the Land Army (french: Armée de Terre, ), is the land-based and largest component of the French Armed Forces. It is responsible to the Government of France, along with the other components of the Armed Force ...

during

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

and

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

History

Before the First World War, the doctrine of the

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 Trench warfare is a type of land warfare using occupied lines largely comprising military trenches, in which troops are well-protected from the enemy's small arms fire and are substantially sheltered from artillery. Trench warfare became ar ...

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 Indirect fire is aiming and firing a projectile without relying on a direct line of sight between the gun and its target, as in the case of direct fire. Aiming is performed by calculating azimuth and inclination, and may include correcting aim ...

interdiction Interdiction is a military term for the act of delaying, disrupting, or destroying enemy forces or supplies en route to the battle area. A distinction is often made between strategic and tactical interdiction. The former refers to operations whose ...

and

counter-battery fire Counter-battery fire (sometimes called counter-fire) is a battlefield tactic employed to defeat the enemy's indirect fire elements (multiple rocket launchers, artillery and mortars), including their target acquisition, as well as their command ...

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. 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 engine A traction engine is a steam engine, steam-powered tractor used to move heavy loads on roads, plough ground or to provide power at a chosen location. The name derives from the Latin ''tractus'', meaning 'drawn', since the prime function of any t ...

s 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.

Design

* The guns - The mle 1914 started life as an order for six coastal defense guns manufactured by Schneider for Denmark. It was a typical

built-up gun A built-up gun is artillery with a specially reinforced barrel. An inner tube of metal stretches within its elastic limit under the pressure of confined powder gases to transmit stress to outer cylinders that are under tension.Fairfield (1921) p. ...

of the period made from steel with a rifled inner tube and reinforced by layers of external tubes. The recoil system for the gun consisted of a U shaped gun cradle which held the

trunnion A trunnion (from Old French "''trognon''", trunk) is a cylindrical protrusion used as a mounting or pivoting point. First associated with cannons, they are an important military development. Alternatively, a trunnion is a shaft that positions a ...

ed barrel and a slightly inclined firing platform with a hydro-gravity recoil system. When the gun fired the hydraulic buffers below the barrel 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. * Traverse and Elevation - The gun carriage employed a car traversing or ''berceau'' system where the car and trucks were placed on a base plate and could be traversed 14°. 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 could elevate between +20° and +65° and loaded at +45°. * The breech - The guns had a semi-automatic

interrupted screw Breech from Russian 122 mm M1910 howitzer, modified and combined with 105 mm H37 howitzer barrel An interrupted screw or interrupted thread is a mechanical device typically used in the breech of artillery guns. It is believed to have be ...

breech that was tied to the recoil system which opened the breech after firing, loaded the next round, closed the breech, and cocked the firing mechanism. Although this system was complicated it gave the mortar a rate of fire of 1 round every two minutes which is high for a system with heavy projectiles. *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 Canon de 240 TR Mle 1903 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,

jackscrew A jackscrew, or screw jack, is a type of jack that is operated by turning a leadscrew. It is commonly used to lift moderately and heavy weights, such as vehicles; to raise and lower the horizontal stabilizers of aircraft; and as adjustable supp ...

s are provided on the car body for transferring from one set of bogies 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 gun fully assembled on standard-gauge rails until near the front and then disassemble the gun and transport it on narrow-gauge rails or on its road wheels. 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.

World War I

The six mle 1914 mortars and four spare barrels were assigned to 61st, 62nd and 63rd batteries of the 25th Group of the 3rd RAP of the ALGP (''artillerie lourde à grande puissance'') on 21 February 1916. On 1 August 1917, the mortars and spares were reorganized into two batteries and assigned to 21st and 22nd batteries of the 11th Group of the 73rd RALGP. They were used during the Battle of the Somme in 1916 and two were sent to reinforce the Italian Front during 1917. All six mortars survived the First world war.

World War II

The six mle 1914 mortars were placed in reserve between the wars. Four were mobilized and deployed by the 371° Regiment of the ALVF (Artillery lourde sur voie ferrée) to reinforce the Maginot Line defenses.

Gallery

File:French 293 mm mortar Model 1903 on railway mounting diagram.jpeg, A mle 1914 showing its loading and maximum elevation. File:Canon de 240 Mle 1903-2.jpg, A schematic of the similar Canon de 240 mle 1903 showing its Berceau mount. File:Canon de 240 Mle 1903-3.jpg, A Canon de 240 mle 1903 carriage placed on road wheels without gun. File:Popular science monthly (1872) (14802579093).jpg, Reassembling a Canon de 240 mle 1903 onsite.

References

{{DEFAULTSORT:Mortier de 293 Danois sur affut-truck modèle 1914 World War I artillery of France Railway guns World War I railway artillery of France World War II artillery of France World War I guns Siege artillery