British Rail Class 171

The British Rail Class 171 Turbostar is a type of diesel-hydraulic multiple unit passenger train built by Bombardier Transportation at Derby Litchurch Lane Works in England. It is identical to the Class 170 except that a Dellner coupler replaces the BSI coupler, a change made so that the units can be joined in an emergency with Class 377 third-rail electric units, which Southern runs on most of its lines. Southern acquired an initial fleet of six two-car Class 171/7 and six four-car Class 171/8 units to replace the slam-door Class 205 and 207 Thumper fleets. The first units entered service in 2003 on the Marshlink Line from Ashford to Hastings, and the trains later worked London Bridge to Uckfield and Eastbourne to Ashford services for Southern.