The Soviet locomotive class P36 () was a Soviet mainline passenger steam locomotive type. Between 1950 and 1956, 251 locomotives were built. The locomotives were nicknamed "Generals" because of the red stripe down the side. The P36 had the same power as a class IS locomotive but the axle loading of 18 tons allowed its use on the vast majority of Russian railway lines, replacing class Su 2-6-2s and significantly increasing the weight of passenger trains. The P36 was the last type of mainline steam locomotive built in the Russian SFSR and the last one built, P36-0251, was the last steam locomotive produced by Kolomna Works, Russian SFSR. Though sometimes described as the "Victory" type locomotive, that moniker actually belongs to the class L 2-10-0 built between 1945 and 1947. Development Background By the early 1940s, the backbone of the Soviet passenger fleet was the class Su 2-6-2, of which more than 2,000 examples were in service. These locomotives had been designed in the 1920s and had a reputation as reliable and economical performers. Axle load was 18 tons, which permitted their use on the majority of the Soviet rail system. However they were not overly powerful (about 1500 hp), which prevented their use with longer passenger trains. In 1932 Kolomna Works began production on a new 2-8-4 locomotive, designed in 1930 and designated class IS (for "Iosif Stalin"). The class IS had more power than the class Su (about 2500 hp) and shared many components with the class FD 2-10-2 freight locomotive, easing repairs. It became the new premier passenger locomotive on the Soviet railway system but its higher axle loading (20.2 tons) meant that its use was restricted to only certain lines. Following the end of the Second World War, railway traffic increased as the national economy recovered. New passenger locomotives with 18-ton axle loading were needed, as the class Su locomotives were often needed in double-headed configuration. Design In 1946 the All-Union Scientific Research Institute of Railway Transport (VNIIZhT) published basic requirements for a new passenger locomotive. Based on results from the two primary existing types of passenger locomotive, the class C and the class IS, four possible types were proposed: 3000 hp (equivalent to a class UU locomotive) - either 4-8-4 or 4-6-4 wheel arrangement with 22.5 ton axle load 2500 hp (equivalent to a class IS locomotive) - either 4-8-4 or 2-8-4 wheel arrangement with