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 be by 2030 nearly twice what they originally assumed. This would mean that diesel locomotives would be releasing more than 800,000 tons of nitrogen oxide and 25,000 tons of soot every year within a quarter of a century, in contrast to the EPA's previous projections of 480,000 tons of nitrogen dioxide and 12,000 tons of soot. Since this was discovered, to reduce the effects of the diesel locomotive on humans (who are breathing the noxious emissions) and on plants and animals, it is considered practical to install traps in the diesel engines to reduce pollution levels and other forms (e.g.,