class-127-dmu

The BR Class 127 was a specialist four-car diesel multiple unit built by British Railways Derby Works in 1959 specifically for the intensive St Pancras–Bedford suburban service on the Midland Main Line — one of BR's busiest commuter routes and one that demanded higher-performance DMU equipment than the standard rural first-generation types could provide. The Class 127 used a unique power plant: four Rolls-Royce C8NFR diesel engines per four-car set (one per vehicle), giving a total output significantly higher than the standard first-generation DMU types and providing the acceleration needed for the short inter-station distances and heavy peak-hour loadings of the St Pancras–Bedford commuter service.

The Rolls-Royce engine specification was distinctive: BR's standard DMU power plants were the AEC or Leyland BUT units, and the choice of the Rolls-Royce C8NFR for the Class 127 reflected the higher power requirements of the intensive suburban service where frequent stops on a busy commuter route demanded more rapid acceleration than the standard rural units could deliver. The four-car formation was also substantially larger than the two or three-car rural DMU sets, reflecting the higher passenger volumes of the Bedford commuter traffic.

The Class 127 worked the St Pancras–Bedford service from 1959 until electrification of the route in 1983, when the sets became redundant. One vehicle is preserved: 51610.