British Diesels and Electrics: Class 171 Turbostar

The Class 171 is part of the Turbostar family of diesel multiple units. It has been built for the non-electrified routes operated by Southern such as the Oxted line.

Southern 171 201 at Oxted

Information
Number built:	56 (20 2 or 4-car sets)
Built:	1999-2004
Builder:	Adtranz / Bombardier Derby
Motor:	MTU 6R 183TD diesel per car
Power:	422 hp (315 kW) per motor car
Formation:	(171/2 or 7) DMCL(W) (Driving Motor Composite Lavatory Wheelchair) + DMSL(W) (Driving Motor Standard Lavatory Wheelchair) (171/4 or 8) DMOCL(W)+MS (Motor Standard)+MS+DMOSL

In 1999 South Central (later Southern) bought six two-car Class 171/7s and six four-car Class 171/8s to replace it's Class 205 and 207 DEMUs on the non-electrified parts of it's network [1]. They are used on the Marshlink and Oxted lines. As time has gone on some Class 170s have been transferred to strengthen the fleet and reclassified as Class 171s (171/2 and 171/8 depending on the number of cars).

The Class 171 is nearly identical to the Class 170 but one difference is the fitting of a Deliner 12 coupler instead of the BSI coupler fitted to other Turbostars. This is so the Class 171 can be coupled to Southern's Class 377 EMUs.

It is planned to transfer the Class 171s to East Midlands Railway (and convert them back to Class 170) in 2021 [2].