Gas turbine train

A gas turbine train is a passenger train that uses one or more gas turbines as its main source of power. Few passenger trains use this system today, although there has been one recent prototype built by Bombardier Transportation.

A gas turbine train typically consists of two power cars (one at each end of the train), and one or more intermediate passenger cars.

In a gas turbine power car a turbine engine, similar to a turboshaft engine, drives an output shaft that is in turn attached to a hydraulic or electric transmission, or (in the case of the UAC TurboTrain) a mechanical gearbox, which supplies power to drive the wheels.

A gas turbine offers some advantages over a piston engine. There are few moving parts, decreasing the need for lubrication and potentially reducing maintenance costs, and the power-to-weight ratio is much higher. A turbine of a given power output is also physically smaller than an equally powerful piston engine, often allowing the power car to accommodate passengers or cargo as well. However, a turbine's power output and efficiency both drop dramatically with rotational speed, unlike a piston engine, which has a comparatively flat power curve.

British Railways invested in experimentation with the new jet turbines in the early to mid 1950s. Most examples were built for the Western region (because of the oversized loading gauge compared with the rest of the network). The last attempt before APT-E was GT3 in 1962, but by then British Rail had favoured diesel and electric locomotives, and the project was scrapped.

The gas turbine investigations were rekindled with the construction of British Rail APT-E, prototype of the Advanced Passenger Train. Like the French TGV, later models were electric instead.

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