Electric transmission (rail)

Diesel-electric transmission, or diesel-electric powertrain is used by a number of vehicle and ship types for providing locomotion.

A diesel-electric transmission system includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors. No clutch is required. Before diesel engines came into widespread use, a similar system, using a petrol (gasoline) engine and called petrol-electric or gas-electric, was sometimes used.

Diesel-electric transmission is used on railways by diesel electric locomotives and diesel electric multiple units, as electric motors are able to supply full torque at 0 RPM. Diesel-electric systems are also used in submarines and surface ships and some land vehicles.

In some high-efficiency applications, electrical energy may be stored in rechargeable batteries, in which case these vehicles can be considered as a class of hybrid electric vehicle.

The first diesel motorship was also the first diesel-electric ship, the Russian tanker Vandal from Branobel, which was launched in 1903. Steam turbine-electric propulsion has been in use since the 1920s (Tennessee-class battleships), using diesel-electric powerplants in surface ships has increased lately. The Finnish coastal defence ships Ilmarinen and Väinämöinen laid down in 1928–1929, were among the first surface ships to use diesel-electric transmission. Later, the technology was used in diesel powered icebreakers.

...
Wikipedia