Diesel locomotive set, and went into series production with other streamlined car sets in Germany starting in 1935. In the USA, diesel-electric propulsion was brought to high speed mainline passenger service in late 1934, largely through the research and development efforts of General Motors from 1930–34 and advances in lightweight carbody design by the Budd Company. The economic recovery from the Second World War saw the widespread adoption of diesel locomotives in many countries. They offered greater flexibility and performance than steam locomotives, as well as substantially lower operating and maintenance costs. Diesel–hydraulic transmissions were intrdouced in the 1950s, but from the
Diesel locomotive deliver 1,200 volts (earlier traction "generators", DC to DC, had the capability to deliver only 600 volts). This improvement was accomplished largely through improvements in silicon diode technology. With the capability to deliver 1,200 volts to the traction motors, the necessity for "transition" was eliminated. A common option on diesel–electric locomotives is dynamic (rheostatic) braking. Dynamic braking takes advantage of the fact that the traction motor armatures are always rotating when the locomotive is in motion and that a motor can be made to act as a generator by separately exciting the field winding. When dynamic braking is utilized, the