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
TU2 diesel locomotive the Ways and Communications. The tests were successful, so the TU2 was taken into production. The only factory that produced the TU2 was Kaluga machine factory. The first three locomotives were tested again, in Panevėžys, (Lithuania) and Pärnu, (Estonia). During the tests, the locomotive could run as fast as . But due to the poor tracks on most of the country's narrow gauge railways, the highest allowed speed during normal operation was . TU2 diesel locomotives were produced till 1959; 281 locomotives were built. The locomotives were used on many narrow gauge railways to haul cargo as well as passenger