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British Rail Metro-Cammell Lightweight
An Eastern Region set at Brundall
In service	1955–1981
Manufacturer	Metropolitan Cammell
Scrapped	1967–1969, 1981
Number built	36 sets (72 cars)
Number scrapped	All
Formation	2 car sets: DMBS-DTSL or DMBS-DTCL
Capacity	DMBS: 57 or 53 second class seats DTSL: 72 second class DTCL: 12 first and 53 second class
Operators	British Rail
Specifications
Train length	114 ft 0 in (34.75 m)
Car length	57 ft 0 in (17.37 m)
Width	9 ft 3 in (2.82 m)
Weight	DMBS: 31 long tons 10 cwt (70,500 lb or 32,000 kg) DTSL: 25 long tons 0 cwt (56,000 lb or 25,000 kg)
Prime mover(s)	Two BUT (AEC) 6-cylinder diesels
Power output	150 hp (112 kW) each engine
Transmission	Mechanical: 4-speed epicyclic gearbox
Braking system(s)	Vacuum
Track gauge	4 ft 8+1⁄2 in (1,435 mm)

In 1955, Metropolitan Cammell produced its first lightweight diesel multiple units, the prototypes of what were to become British Rail's most successful and longest-lived First Generation DMU type, the Class 101.

The seven London Midland Region sets (formed DMBS + DTCL) were used on the Bury-Bacup line services, while the other sets (formed DMBS + DTSL) were all allocated to the Eastern Region. These sets were used on a variety of lines in East Anglia as well as the (then) non-electrified lines in Essex (Romford-Upminster and Wickford-Southminster branches).

A unit consisting of 79066 and 79282 worked the last passenger service on the Aldeburgh Branch Line in 1966.^[1]

They proved to be very successful, but with line closures continuing through the 1960s, including many in East Anglia where the type was first used, their non-standard coupling arrangements left them prone to early withdrawal, which took place during 1967–1969.

All were scrapped following withdrawal, except two (79047 + 79053), which were taken into departmental (non-revenue earning) service as 975018 + 975019. They were used at the Railway Technical Centre in Derby as Laboratory 21: Plasma Torch Research. When this extended life was complete, they too were scrapped, in 1981.