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 two different types of turbine-powered trainsets, which were both called Turboliners. The sets of the first type were similar in appearance to SNCF's T 2000 Turbotrain, though compliance with FRA safety regulations made them heavier and slower than the French trains. None of the first-type Turboliners remain in service. Amtrak also added a number of similarly named Rohr Turboliners (or RTL) to its roster. There were plans to rebuild these as RTL IIIs, but the program has been cancelled and the units are being sold or scrapped. In 1966, the Long Island Rail Road tested an experimental gas turbine railcar