A diesel–electric transmission, or diesel–electric powertrain is a transmission system for vehicles powered by diesel engines in , , and transport. Diesel–electric transmission is based on petrol–electric transmission, a very similar transmission system used for petrol engines. 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 marine transport, including submarines, and on some land vehicles.