Diesel locomotive Diesel–hydraulic locomotives have a smaller market share than those with diesel electric transmission - the main worldwide user of main-line hydraulic transmissions was the Federal Republic of Germany, with designs including the 1950s DB class V 200, and the 1960 and 1970s DB Class V 160 family. British Rail introduced a number of diesel hydraulic designs during it 1955 Modernisation Plan, initially license built versions of German designs (see ). In Spain RENFE used high power to weight ratio twin engined German designs to haul high speed trains from the 1960s to 1990s. (see RENFE Classes 340, 350, 352, 353,
Diesel locomotive operate efficiently within a limited torque range, and while low power gasoline engines can be coupled to a mechanical transmission, the more powerful diesel engines required the development of new forms of transmission. The first successful diesel engines used diesel–electric transmissions, and by 1925 a small number of diesel locomotives of were in service in the United States. In 1930, Armstrong Whitworth of the United Kingdom delivered two locomotives using Sulzer-designed engines to Buenos Aires Great Southern Railway of Argentina. In 1933, diesel-electric technology developed by Maybach was used propel the DRG Class SVT 877, a high speed intercity two-car