The Class 170 "Turbostar" is a diesel multiple unit (DMU) built by Bombardier Transportation (and previously ADtranz) at their Derby Litchurch Lane Works, England.
Introduced after privatisation, they have operated as regional trains as well as long-distance trains, and to a lesser extent suburban trains. 122 units have been built.
The class are a continuation of the design used in the British Rail Class 165, 166 and 168 DMUs known as the Networker-turbos which were built by BREL and later ABB Transportation Ltd before that company eventually became part of Bombardier.
Notable features shared are the aluminium alloy frame and Voith transmission as well as the general bodyshape (the cab ends are comparable with the Class 168, but not Class 165/166), interior design and door fittings. The final drive is sourced from ZF instead of Gmeinder and the diesel engine supplier has changed to MTU[2]
The engine, tranmsission are situated under the body (at wheel level), one bogie per coach is powered, the other bogie is unpowered. All coaches in the set are powered (there are no unpowered trailers). The units can work in multiple with British Rail Classes 150 to 170 ie the Sprinters, Networker turbos and other units of the same class.[3]
Seating arrangements are of both 2+1 (first class) and 2+2 (standard class) formation, and gives a seated passenger capacity of between ~100 and ~200 per three car set (depending on the specifications of the operator)[4]. 2 car sets are also operated.
The Class has been categorised into five sub-classes - the basic specifications remain the same (engine, length, transmission etc) - the differences being the seating arrangements specified by the different operators - because of the different interior fittings the sub-classes differ in weight from one another by a small amount: up to ~2 tonnes.[3]
All the subclasses were built at Derby either under AdTranz or Bombardier's ownership.
