The first railway mount for the 8-inch gun was completed and sent to the Aberdeen Proving Ground for test in May, 1918. In early June the test had shown that the weapon was efficient and entirely satisfactory. Before the end of the year 1918 a total of 24 complete units, with ammunition cars for standard-gauge track, shell cars for narrow-gauge track, transportation cars, tools, spare parts, and all the other necessary appurtenances of a unit of this character, had been completed. Three complete 8-inch units were shipped overseas before the armistice was signed. When the armistice came the Harrisburg company had delivered 9 of these mounts and the Morgan Engineering Co. an equal number, making 18 in all. The former concern had reached an output of 5 mounts per month and the latter 10 per month. An interesting feature of this mount is that it can be used either on standard-gauge or on narrow-gauge railroad track. The narrow gauge adopted was that in standard use in the fighting zones in France, the distance between the rails being 60 centimeters, or the approximate equivalent of 24 inches. Each gun car was provided with interchangeable trucks to fit either gauge. The artillery train necessary for the maneuvering of the weapon was also similarly equipped to travel on either sort of track. As a rule the longer the barrel of a cannon, the greater its range. The 8-inch seacoast guns thus mounted were 35 calibers in length, that is, thirty-five times 8 inches, or 23 feet 4 inches. The requirements of our forces in the field in France called for guns of this same size but of longer range. Consequently an 8-inch gun of 50 calibers--that is, 10 feet longer than the seacoast 8-inch gun--was designed, and 25 of them were ordered. This project came as a later development in the war, the guns being intended for use abroad in 1920. The railway mounts for the weapons had not been placed in production when the armistice came. Because of the incomplete status of this project in the autumn of 1918, the whole undertaking was abandoned. 10-INCH AND 12-INCH GUNS. There were at the seacoast defenses and in the stores of the Army a large number of 10-inch guns of 34 calibers. Of these 129 were available for mounting on railway cars. It was proposed to mount these weapons on two types of French railway mounts--the Schneider and the Batignolles. The project to mount 36 of these weapons on Schneider mounts was taken up as a joint operation of the United States and French Governments, the heavy forging and rough machining to be done in this country and the finishing and assembling in the French shops. The American contractors were three. The Harrisburg Manufacturing & Boiler Co. undertook to furnish the major portion of the fabricated materials for the carriages and cars. The Pullman Car Co. contracted to produce the necessary trucks for the gun cars, while the American Car & Foundry Co. engaged to build the ammunition cars.