class-101-dmu

The BR Class 101 was a diesel multiple unit family of 527 vehicles built by Metro-Cammell of Birmingham between 1956 and 1959, forming the most numerous single class of first-generation DMU and one of the defining rolling stock types of the transition from steam to diesel traction on British rural and secondary routes in the late 1950s and 1960s. The Class 101's Metro-Cammell underframe and body construction, with its distinctive wrap-around cab windows and clean external lines, became the visual template for the first-generation BR DMU era, and the class worked rural branch lines, cross-country services, and suburban stopping trains across virtually every region of BR for over three decades.

The diesel multiple unit — self-propelled diesel railcars operating in fixed formations without a separate locomotive — was BR's response to the economics of rural and secondary passenger services where the cost of steam locomotive provision, turning, and servicing made branch line operation unviable. The DMU could be driven from either end, eliminating the need to run a locomotive round at the terminus, and its lighter weight and lower maintenance costs compared with a locomotive-hauled formation transformed the economics of secondary passenger working. The Class 101's AEC or Leyland diesel engines mounted under the floor gave adequate performance for rural and cross-country stopping services, while the comfortable interior with large windows suited the passenger market BR was trying to retain against growing car ownership.

The Class 101 was formally withdrawn from BR service by 2003, the last of the first-generation DMU fleet to remain in regular service. Six vehicles are preserved on heritage railways.