 In 1944, SNCF reviewed its predicted postwar traffic requirements and determined a requirement for a locomotive capable of hauling passenger trains of 700–800 tonnes at , and capable of climbing gradients of 1 in 125 (8‰).A prototype 4-8-2 four cylinder compound locomotive, the 241.C.1, had been built by Schneider et Cie. in 1930 for the former Chemins de fer de Paris à Lyon et à la Méditerranée (PLM).This locomotive was utilised as the basis for the new class, but with some key design changes including the addition of an automatic stoker, strengthened frames, and boiler modifications.