The British Rail Class 170, commonly known by its family name Turbostar, is a diesel multiple unit designed for regional and intercity services across the United Kingdom. It was manufactured for the post-privatisation rail market and became one of the most numerous DMU types of its era. The design emphasises modular components, flexible train lengths and relatively high top speeds for non-electrified routes.

Design and characteristics

Class 170 trains are offered in two- and three-car formations that can be coupled together for longer trains. They feature a single-deck passenger layout with a mix of seating for short and medium-distance journeys, standard-class accommodation and on-board heating and air-conditioning in most sets. The units were built with conventional diesel traction, mechanical and electrical subsystems that are designed to be maintained in regional depots.

Manufacture and development

The fleet was produced by Bombardier Transportation (initially ADtranz) at the Derby Litchurch Lane Works, a long-established British railway factory located in Derby, England. The Turbostar family followed earlier DMU designs and addressed a market need for modern, reliable diesel units after railway privatisation. The Class 170 shares many components and an overall appearance with related Turbostar types, allowing operators to standardise maintenance practices.

Operational use and examples

Operators have deployed Class 170 units on regional, rural and inter-regional services where electrification is absent. Their ability to reach higher speeds than older DMUs made them suitable for services that require faster journey times on secondary main lines. Over time the units have been repainted, refurbished and internally reconfigured to suit different operators' needs and passenger expectations.

  • The Turbostar family includes several related classes; the Class 170 is one of the best-known examples and is often mentioned alongside others such as the Class 168 and Class 172.
  • Some variants designed for specific networks use different coupling or gangway arrangements; for example, closely related types have alternate couplers to match network standards.
  • Overall, the Class 170 is frequently cited as the most numerous DMU introduced in the period after British rail privatisation, reflecting its popularity with many train operating companies.

For further technical specifications, refurbishment histories and operator lists consult detailed rolling-stock references or the manufacturer’s product pages. Additional background on the Turbostar family and diesel multiple units can be found via authoritative rail industry sources: Turbostar overview, diesel multiple units (DMU), and the manufacturer's pages at Bombardier. Local history of the production site is available through resources about Derby Litchurch Lane Works and its role in UK rail manufacturing in England.