British Rail Class 100

British Rail Class 100
Class 100, no. 56301 at County School Station on the Mid-Norfolk Railway on 17 December 2001. This unit was the first heritage DMU vehicle to enter preservation.
In service	1957–1988
Manufacturer	Gloucester Railway Carriage and Wagon Company
Constructed	1957–1958
Number built	40 sets (80 cars)
Number preserved	4 cars
Formation	2 cars sets: DMBS-DTCL
Capacity	DMBS: 52 second class seats, DMCL: 12 first and 54 second class seats
Operator(s)	British Rail
Specifications
Car length	57 ft 6 in (17.53 m)
Width	9 ft 3 in (2.82 m)
Height	12 ft 8 1⁄2 in (3.87 m)
Maximum speed	70 mph (113 km/h)
Weight	DMBS: 30 long tons 5 cwt (67,700 lb or 30,700 kg), DMCL: 24 tons 15 cwt (55,400 lb or 25,100 kg)
Prime mover(s)	Two BUT 6-cylinder diesel engines
Power output	150 bhp (112 kW) per engine
Transmission	Mechanical: 4-speed epicyclic gearbox
Braking system(s)	Vacuum
Coupling system	Screw-link couplings, British Standard gangways
Multiple working	■ Blue Square
Track gauge	4 ft 8 1⁄2 in (1,435 mm)

The British Rail Class 100 diesel multiple units were built by Gloucester Railway Carriage and Wagon Company Limited from 1956 to 1958, designed and built in collaboration with the Transport Sales Dept. of T.I. (Group Services) Ltd.

The class were designed to be lightweight to allow for good acceleration. None were selected for refurbishment and withdrawals started in 1969. The last passenger car was withdrawn from service in 1988.

Under initial classification 1973, the DTCs became 143s, but were later reclassified as 100s.

56111 was used as a training aid by the Ministry of Defence until 1985. Two sets entered departmental service: 51122 and 56300 became ADB975664 and ADB975637 for use as the "Stourton Saloon" – the Eastern Region General Manager's saloon – for which the class gained a small amount of "fame"; these were scrapped in 1990. The other pair were ADB975349 and ADB975539 (ex 51116 and 56101) and were used as the Eastern Region inspection saloon, until being scrapped in 1993. 56106 survived the longest time on the national network, being scrapped in 2000.

Trailer car 56301 was the first diesel multiple unit car to enter preservation in 1969, originally being used at the Chasewater Railway.

The Class has not fared well in preservation. 7 cars entered preservation of which only 3 now exist. 50341 and 56099 were preserved by the West Somerset Railway, but were scrapped & dismantled in 1991. The National Railway Museum had intended to preserve 53355 (ex 50355), but a lack of space prevented this car, and the Class 105 coupled to it from being moved to York and they were vandalised beyond repair at Crewe. DTCL 56317 was scrapped in early 2017.