British Rail Class 120

British Rail Class 120 Swindon 3-car Cross-country sets

In service	1958–1989
Manufacturer	British Railways
Order no.	30334 (50647-50695) 30335 (50696-50744) 30336 (59255-59301) 30515 (51573-51581) 30516 (51582-51590) 30517 (59579-59588) 30559 (51781-51787) 30560 (51788-51794) 30561 (59679-59685)
Built at	BR Swindon Works
Constructed	1957–1960
Number built	194 cars
Number preserved	1 car (a TSLRB)
Number scrapped	193 cars
Formation	3 car sets: DMSL-TSL[RB]-DMBC
Diagram	DP204 or BR586 DP205 or BR637 DQ101 or BR587 DQ303 or BR587 DQ304 or BR636 DT210 or BR572 DT217 or BR561
Fleet numbers	51573-51581, 51781-51787, 53696-53744 (DMBC) 59255-59301, 59579-59588, 59679-59685 (TSLRB) 50647-50695, 51582-51590, 51788-51794 (DMSL)
Capacity	DMC: 18 first class and 16 second class seats DMSL: 68 second class seats TSLRB: 60 second class seats TSL: 68 second class seats
Operator(s)	British Rail
Depot(s)	Cambridge Chester Haymarket Reading Derby TMD
Specifications
Car body construction	Steel
Car length	64 ft 7 ⁷⁄₁₆ in (19.70 m) (DP205, DQ304, over body) 64 ft 6 ¹⁄₈ in (19.66 m) (others, over body)
Width	9 ft 3 in (2.82 m) (overall)
Height	12 ft 9 ¹⁄₂ in (3.90 m) (overall)
Doors	Slam
Wheelbase	46 ft 6 in (14.17 m) (bogie centres) 8 ft 6 in (2.59 m) (bogies)
Maximum speed	70 mph (113 km/h)
Weight	Dia 586: 36.50 long tons (37.09 t; 40.88 short tons) Dia 587: 36.35 long tons (36.93 t; 40.71 short tons) Dia 561: 30.60 long tons (31.09 t; 34.27 short tons) Dia 636: 36.95 long tons (37.54 t; 41.38 short tons) Dia 637: 37.05 long tons (37.64 t; 41.50 short tons) Dia 572: 30.15 long tons (30.63 t; 33.77 short tons)
Prime mover(s)	Two BUT (AEC) of 150 hp (110 kW) per power car
Power output	600 hp (447 kW) per 3-car set
Transmission	Standard mechanical
Train heating	Oil burning air heater
Bogies	DD1 mk1 and mk2 (one of each) DD2 mk1 and mk2 (one of each) DT3 mk1 and mk2 (one of each)
Braking system(s)	Vacuum
Safety system(s)	AWS
Coupling system	Screw
Multiple working	■ Blue Square
Track gauge	4 ft 8 ¹⁄₂ in (1,435 mm)

The Class 120, were a cross-country DMU in three-car formation, built at the British Rail Swindon Works.

Totalling 194 cars, three batches were built:

British Railways placed the order with British United Traction in summer 1956 for the equipment required for the 98 power cars and 47 trailers of the first batch. The order, along with equipment ordered by Cravens for 66 power cars and the 3 parcels cars, was valued at £830,000. The first batch was ordered for the WR's West Country dieselisation scheme, which it hoped to complete by the end of 1959. The sets were expected to work between Bristol & South Devon. Their general reliability and good braking characteristics made them popular with drivers.

In February 1959, the BTC placed an order with BUT for the equipment for the seven ScR sets, along with equipment for Class 108s and 127s being built at Derby. These 120s were to work mainly on the Aberdeen to Inverness line although appearances at Oban were not unknown. Otherwise the cars worked mainly in the Western and Midland Regions.

Some cars had a trial refurbishment but this was found to be too expensive, meaning an early withdrawal for most of the class. Some of the London Midland Region's units were transferred to Scotland in the mid-1980s, mainly finding use on local services from Edinburgh (notably to North Berwick). The final vehicles survived until 1989.

One trailer car survives at the Great Central Railway: 59276 (TSLRB).

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