Class 159

| Technical Data Total Built: 22 Weight: 37.8t Length: 23.20m (76ft 1.25in) Engine Power: 400hp (300kW) Max Speed: 90mph (145km/h)

In the late 1980s, the locomotive-hauled stock on Network SouthEast's West of England route from London Waterloo to Salisbury, Yeovil, Bristol, Bath and Exeter was in urgent need of replacement. The British Rail Class 50 locomotives were not suited to the stop-start nature of the route, and frequently broke down.

The original 22 units were built as Class 158 units, but were rebuilt by Babcock Rail in Rosyth Dockyard before entering traffic. This entailed fitting first-class accommodation, septic tanks and various other modifications. The rebuild was required because it was not possible for Network SouthEast and the newly privatised BREL to agree terms on the variation order to NSE specification.

The first unit (159004) was handed over to NSE on 6 January 1993.

In 2000 South West Trains began a refurbishment programme for its 22 Class 159/0s. The seats were re-trimmed and interiors repainted. The units were repainted into SWT livery.

Their reliability has been consistently good since their introduction in 1992-1993. They are fitted with the Cummins NTA 855R engine, providing 300kW (400hp) through a Voith transmission to a Gmeinder final drive. They were expected to achieve 13,500 miles of operation between major services and a range of up to 1,600 miles from each refuelling.