Credit to RailfanEthan for the carriage. The 12"/15 caliber Railway Howitzer, M1922 is an American railway artillery piece designed to knock down heavy fortifications, due to requirements for such weapon in the Great War. As such, 25 pieces were built. However, the weapon entered service too late to see service, and was placed in storage. When the Paternian War broke out in 1933, these guns would see service in both the hands of the Paternian Republic and Southern Confederacy. It was employed as a fortification-busting weapon on both sides. However, advances in air power, notably the Paternian introduction of the B-17 Flying Fortress in 1936, rendered these weapons obsolete. By 1940, all Paternian guns were scrapped. Confederate guns would remain in service until the end of the war, employed as a force-in-being; never employed due to the high vulnerability and risk of loss, but kept in an area so that Paternian forces must plan around it in case it is employed.