The British Rail Class 171 Turbostar is a type of diesel multiple unit (DMU) passenger train built by Bombardier Transportation at Derby Litchurch Lane Works in England. It is identical to the Class 170, except for the replacement of the BSI coupler with a Dellner coupler. This provision was made to allow emergency joining with Class 377 DC third-rail electric units, which Southern runs extensively on most lines. The units work on the southern regions of the British railway system, operating services from London Bridge to Uckfield and from Eastbourne to Ashford International, these routes being unelectrified between Hurst Green Junction and Uckfield and between Ore and Ashford International, respectively.
Southern 171721 at Hastings in 2014
The Standard Class interior aboard a Class 171
A class 171 at Pevensey & Westham
First Class section of a Class 171
A diesel multiple unit or DMU is a multiple-unit train powered by on-board diesel engines. A DMU requires no separate locomotive, as the engines are incorporated into one or more of the carriages. Diesel-powered single-unit railcars are also generally classed as DMUs. Diesel-powered units may be further classified by their transmission type: diesel–mechanical DMMU, diesel–hydraulic DHMU, or diesel–electric DEMU.
A JNR Class KiHa40 in use for Erimo Express service, Hokkaido, Japan
An IE 29000 Class diesel multiple unit on a western commuter service at Dublin Connolly Rail station, Ireland
A British Rail Class 185 diesel hydraulic multiple unit operated by TransPennine Express at Manchester Piccadilly station, United Kingdom
One of the underfloor diesel engines with hydraulic transmission under a car of JR Shikoku 2700 series DMU