After the end of the war, Klöckner-Humboldt-Deutz was one of the first locomotive builders to be able to resume full-scale production. The first newly developed model was the V6M 436 R, which, however, was based directly on the WR 360 C 14. The designation actually stood for the engine and meant “four-stroke, 6 cylinders, water-cooled, 4th generation, 36 cm piston stroke, standard gauge” and also referred to the locomotive. The transmission was still via a Voith torque converter on a jackshaft between the second and third axle, which in turn drove coupling rods. The 536 R already used a fifth-generation engine that produced 450 hp. From 1955, both had a higher driver's cab, which improved the view to the front.
The 436 R was built a total of 27 times from 1948 to 1958 and was mainly sold to customers in Germany. The Bundesbahn, Bundespost, Volkswagen and the ports of Hanover each ordered two to four locomotives, otherwise all other customers only ordered one example. The 536 R was built a total of 35 times from 1952 and was mainly used directly abroad. The export customers were in Sweden, the Netherlands and Luxembourg. In Luxembourg they were run by the CFL as class 450. Two pieces were delivered to the US Army in Europe and one to the British Army of the Rhine.
