class-117-dmu

The BR Class 117 was a family of 84 three-car diesel multiple unit sets built by Pressed Steel of Oxford in 1959–61 for the Western Region of British Railways, providing suburban and semi-fast stopping passenger services on the WR routes out of Paddington and Reading to the Thames Valley, Cotswolds, and associated suburban catchment area. The Class 117 was a Pressed Steel interpretation of the first-generation DMU formula, with a slightly more angular body styling than the Metro-Cammell Class 101 but similar mechanical specification using BUT (AEC/Leyland) diesel engines and mechanical transmission.

The Western Region's suburban services in the Thames Valley — the Reading, Oxford, Didcot, and Newbury lines and the associated stopping services to the growing commuter towns west of London — demanded a capable and comfortable three-car suburban DMU that could handle both peak commuter flows and off-peak rural stopping services on the same diagrams. The Class 117 fulfilled this requirement, giving the WR a standardised suburban fleet for the routes that the GWR had previously worked with steam pannier tanks and auto-trains.

Two vehicles are preserved: 51410 and L401.