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 fully insulated electrical system (neither side earthed to the frame) and all electric wiring enclosed in conduit. The flameproof diesel locomotive has replaced the fireless steam locomotive in areas of high fire risk such as oil refineries and ammunition dumps. Preserved examples of flameproof diesel locomotives include: Latest development of the "Flameproof Diesel Vehicle Applied New Exhaust Gas Dry Type Treatment System” does not need the water supply. The lights fitted to diesel locomotives vary from country to country. North American locomotives are fitted with two headlights (for safety in case one malfunctions) and a pair of ditch lights. The