British Rail Class 117

The British Rail Class 117 diesel multiple units (DMUs) were built by Pressed Steel from 1959 to 1961.

When first introduced, these three-car units were all based with the similar Class 121 single carriage (railcar) units on British Railway's Western Region for suburban work out of London Paddington and Cornwall. The units were largely based at Southall, and Plymouth Laira depots. The units remained here for many years working these services.

Later operations
In the 1980s, expiry of other DMUs facilitated moves for some units from the Western Region to Birmingham, as below, and Scotland, prior to the delivery of new units to replace them. They were given refurbishments.

The first shake up in ownership occurred in the late 1980s, when the Scottish, Welsh, Cornish and Birmingham based units were transferred to Provincial Services, later Regional Railways, in the sectorisation of British Rail, while the Southall-based units transferred to Network SouthEast.

They were replaced on the lines out of Paddington when the Class 165 'Network Turbo' units came into service in 1990-91.

They soldiered on in the former Western Region until replaced by Class 150 and Class 153 DMUs by 1991.

They additionally soldiered on to the Wales network until it began retirement in 1995, being replaced by more Class 150s and Class 153s freed up from other areas.

They continued to work in Scotland until 1998, where they were replaced with additional cascades of Class 156s and Class 170 Turbostar DMUs.

For many years, passenger services on the Birmingham Cross-City Line were worked by elderly Class 117, along with Class 115, 116, 118 and 121 diesel multiple units, but all were withdrawn from service by 1995 and replaced by Class 323s.

In 2000, Class 150 Sprinter units replaced the Class 117 units on Silverlink following deliveries of Turbostar, finally bringing to an end decades of service on Britain's rail network in front line service.

Once in preservation it has since been discovered that the units had all sorts of Leyland 680 engine variants.. For example, one unit was noted as having a Leyland 680/1 (150 BHP) and a Leyland 680-1595  (180 BHP).

Preservation
Due to the type's longevity, 12 units have been preserved on heritage railways.