Steam and diesel engines, due to their weight, are usually designed into a dedicated locomotive car; because turbojet engines, similarly to gas turbine engines, are lighter, they have been built with the engine incorporated into a railcar combining both propulsion and passenger accommodation rather than as separate locomotives hauling passenger coaches.
Turbojet engines are most efficient at high speeds[note 1] and so they have been applied to high-speed passenger services, rather than freight.
Monument at the rail-car factory in Tver depicting a Turbojet train
Another turbojet railcar, SVL (High-speed Laboratory Railcar), was built in the USSR in 1970. The SVL was able to reach a speed of 250 kilometres per hour (160 mph). This locomotive was built on a basis of the main engine railcar of ER22 electric multiple unit. It had a mass of 54.4 tonnes (including 7.4 tonnes of fuel) and was 28 metres (92 ft) long. The power car was planned to be used as a part of "Russian troika" express.