Gas turbine on and off to run it only at high efficiency. The emergence of the continuously variable transmission may also alleviate the responsiveness problem. Turbines have historically been more expensive to produce than piston engines, though this is partly because piston engines have been mass-produced in huge quantities for decades, while small gas turbine engines are rarities; however, turbines are mass-produced in the closely related form of the turbocharger. The turbocharger is basically a compact and simple free shaft radial gas turbine which is driven by the piston engine's exhaust gas. The centripetal turbine wheel drives a centrifugal compressor wheel through
Gas turbine locomotive and many were taken out of service. Additionally, Union Pacific's locomotives required more maintenance than originally anticipated, due to fouling of the turbine blades by the Bunker C oil used as fuel. In 1939 the Swiss Federal Railways ordered a GTEL with a of maximum engine power from Brown Boveri. It was completed in 1941, and then underwent testing before entering regular service. The Am 4/6 was the world's first gas turbine-electric locomotive. It was intended primarily to work light, fast, passenger trains on routes which normally handle insufficient traffic to justify electrification. Two gas turbine locomotives of different design,