From the late 1950s diesel multiple units (DMUs) started to replace steam traction on Britain's railway network. By 1968 the transition was complete and these multiple units could be seen throughout the UK from humble branch lines to busy commuter services. In turn these early DMUs have been replaced by the modern versions we are all now used to travelling on.
Fortunately you can still experience the pleasure of riding in these 50 year old units on the GWSR. Normally comprising cars W51405 (DMS), W59510 (TCL), W51363 (DMBS), this Class 117 unit was purchased in 2011 by Cotswold Diesel Railcar Limited and is now running regular services from Toddington. Note that, at present, W51360 (DMBS) is running in place of W51405 to allow refurbishment of the DMS.