Diesel locomotive Calabro Lucane in southern Italy in 1926, following trials in 1924-5. In 1924, two diesel–electric locomotives were taken in service by the Soviet railways, almost at one time: In 1935, Krauss-Maffei, MAN and Voith built the first diesel–hydraulic locomotive, called V 140, in Germany. The German railways (DRG) being very pleased with the performance of that engine, diesel–hydraulics became the mainstream in diesel locomotives in Germany. Serial production of diesel locomotives in Germany began after World War II. In many railway stations and industrial compounds, steam shunters had to be kept hot during lots of breaks between scattered short tasks.
Electro-diesel locomotive take advantage of shorter sections of electrified main lines. Bombardier has built dual-mode variants of its AGC series for the French operator SNCF; the electricity is collected by means of a pantograph. In Russia, a number of electro-diesels were built which had both pantographs and diesel prime movers; these locomotives were actually multiple units, with distinct electric, diesel, and motor sections. These included: An experimental electro-diesel locomotive, DEL120, was built by London Underground in 1940 but was not a success. Two types have been built whose electricity source was a 750 V DC third rail. Electro-diesel locomotives and multiple units