British Rail 18000 was a prototype mainline gas turbine–electric locomotive built for British Railways in 1949 by Brown, Boveri & Cie. An earlier gas-turbine locomotive, 18100, had been ordered from Metropolitan-Vickers by the Great Western Railway but construction was delayed due to World War II; a second, 18000, was thus ordered from Switzerland in 1946.

[1] It spent its working life on the Western Region of British Railways, operating express passenger services from Paddington station, London.

After allowing for transmission losses, this would be down to about 1,300 hp (970 kW) at the rail, so two diesels would be needed to match a King.

After leaving the heat exchanger, the pre-heated air entered a large, vertical, combustion chamber where the fuel was injected and burned.

The diesel engine was capable of moving the locomotive at a slow speed when the gas turbine was not running.

The usual procedure was to run the locomotive from the shed to Paddington station using the diesel engine and to start the gas turbine only a few minutes before the train was due to leave.

The efficiency of a gas turbine reduces dramatically at low power outputs so, to achieve respectable fuel economy, a gas turbine locomotive needs to be operated as much as possible at full power, with periods of part-load running reduced to a minimum.

Unfortunately, however, it was neither possible to achieve a consistently acceptable level of reliability nor to operate it under conditions which would allow reasonable fuel economy.

In 1975 it was moved to Vienna and displayed outside the Mechanical Engineering Testing building of the Arsenal research centre.