28 cm K L / 40 " Kurfürst " The 28 cm K L / 40 " Kurfürst " ( K - Kanone ( Cannon ) L - Länge ( with a 40 caliber barrel ) , Kurfürst ( " Elector " ) was a German railroad gun that served on the Western Front in 1918 during World War I . Originally a naval gun , it was adapted for land service when its original ships began to be disarmed beginning in 1915 . All six built were destroyed postwar according to the terms of the Treaty of Versailles . Design . These guns were used as the main armament of the pre - dreadnoughts and , but they were transferred to the Army from the Navy ( Kaiserliche Marine ) when those ships began to be relegated to training duties in 1915 . Six guns were mounted on the " Eisenbahn und Bettungsschiessgerüst " ( " E . u . B . " ) ( railroad and firing platform ) mounts successfully used by other German railroad guns . Unlike every other large German railroad gun , it used a massive rectangular cradle for its gun . The " E . u . B . " could fire from any suitable section of track after curved wedges were bolted to the track behind each wheel to absorb any residual recoil after the gun cradle recoiled backwards . It also had a pintle built into the underside of the front of the mount . Two large rollers were fitted to the underside of the mount at the rear . Seven cars could carry a portable metal firing platform ( " Bettungslafette " ) that had a central pivot mount and an outer rail . It was assembled with the aid of a derrick or crane , which took between three and five days , and railroad tracks were laid slightly past the firing platform to accommodate the front bogies of the gun . The gun was moved over the firing platform and then lowered into position after the central section of rail was removed . After the gun ' s pintle was bolted to the firing platform ' s pivot mount , the entire carriage was jacked up so that the trucks and their sections of rail could be removed . The carriage was then lowered so that the rear rollers rested on the outer track . Concrete versions were also used . It could have up to 360° of traverse . The " E . u . B . " retained 4° of on - mount traverse for fine aiming adjustments . Ammunition . Ammunition was moved by means of an overhead rail from which a shell trolley carried individual shells to be placed in the loading tray fixed to the breech . An extensible rail could raised and braced in place to allow the shell trolley to reach shells placed on the ground or in an ammunition car behind the mount . This ammunition car sometimes had its own overhead rail to move the shells forward to where the trolley in the mount could reach it through a hatch in the roof . The shell and powder were manually rammed into the gun . The gun had to be loaded at zero elevation and thus needed to be re - aimed between each shot . It used the German naval system of ammunition , where the base charge was held in a metallic cartridge case and supplemented by another charge in a silk bag that was rammed first . Combat History . The six " Kurfürst " guns entered service in early 1918 , participating in the German Spring Offensive and the subsequent defensive operations . They were organized into Batteries 393 , 434 , 722 and the First through Third Batteries of " Bavarian Foot Artillery Battalion ( 1 . - 3 . / Bayerische Fußartillerie - Batallion ) 29 " with one gun each . All six were destroyed in 1921 – 22 by the Military Inter - Allied Commission of Control .