Diesel locomotive Dv12s. In the 21st century series production standard gauge diesel–hydraulic designs include the Voith Gravita, ordered by Deutsche Bahn, and the Vossloh G2000, G1206 and G1700 designs, all manufactured in Germany for freight use. Steam-diesel hybrid locomotives can use steam generated from a boiler or diesel to power a piston engine. The "Cristiani Compressed Steam System" used a diesel engine to power a compressor to drive and recirculate steam produced by a boiler; effectively using steam as the power transmission medium, with the diesel engine being the prime mover The diesel-pneumatic locomotive was of interest in the 1930s because it
Diesel locomotive made (e.g., the British Rail 10100 locomotive), although none have proved successful in the end. In a diesel–electric locomotive, the diesel engine drives either an electrical DC generator (generally, less than net for traction), or an electrical AC alternator-rectifier (generally net or more for traction), the output of which provides power to the traction motors that drive the locomotive. There is no mechanical connection between the diesel engine and the wheels. The important components of diesel–electric propulsion are the diesel engine (also known as the prime mover), the main generator/alternator-rectifier, traction motors (usually with four or six axles), and a