British Rail Class 12

British Rail Class 12
Power type	Diesel-electric
Builder	British Railways’ Ashford Works
Order number	SR 3413 (15), 3537 (11)
Build date	1949–1952
Total produced	26
Configuration	0-6-0
UIC classification	C
Gauge	4 ft 8 1⁄2 in (1,435 mm) Standard gauge
Wheel diameter	4 ft 6 in (1.372 m)
Wheelbase	11 ft 6 in (3.51 m)
Length	29 ft 5 1⁄2 in (8.98 m)
Width	9 ft 0 in (2.74 m)
Height	12 ft 8 1⁄2 in (3.87 m)
Locomotive weight	48 long tons (48.8 t)
Fuel capacity	660 imp gal (3,000 l; 790 US gal)
Prime mover	English Electric 6KT
Traction motors	English Electric 506A, 2 off
Transmission	DC generator, DC traction motors, double reduction gearing
Multiple working	Not fitted
Top speed	27.5 mph (44.3 km/h)
Power output	Engine: 350 hp (261 kW)
Tractive effort	Maximum: 24,600 lbf (109.4 kN)
Train heating	None
Train brakes	None; 15230–15232 Air from 1970
Career	British Railways
Number	15211–15236
Axle load class	RA 5

The British Rail Class 12 is a diesel locomotive built primarily for shunting duties around London.

History

This was the second batch of Southern Railway shunters based on the English Electric 6KT 350 hp (260 kW) diesel engine. The first experimental batch (BR numbers 15201-15203) were designed by Richard Maunsell of the SR in 1937 and were later classified D3/12. These locomotives were Oliver Bulleid's development of Maunsell's original design, but were significantly lighter. They featured Bulleid's distinctive Boxpok wheels, and incorporated a number of details from the diesel-electric shunters produced by the London Midland and Scottish Railway 1936-39. They were built at the BR Ashford Works over the period 1949–1952 and numbered 15211–15236. They later became Class 12, but no locomotives survived long enough to acquire Class 12 TOPS numbers.

Technical details

The diesel engine is an English Electric 6-cylinder, 4-stroke, 6KT and the traction motors are 2 x EE506 axle-hung, nose-suspended, force-ventilated traction motors with 17.5:1 double reduction gear drive. The main generator is an EE type EE801/7D, flange-mounted single bearing rated at 490 kW.

Operational details

The locomotives were designed for use in the two south London marshalling yards at Norwood Junction and Hither Green, and remained there for much of their working lives. Later some examples were used as works shunters at Ashford, Brighton and Eastleigh.

Withdrawal

The entire class was withdrawn between 1968 and 1971 and most were cut up soon afterwards. The only surviving locomotive of the class is 15224, located at the Spa Valley Railway, Royal Tunbridge Wells.

Further reading

• McManus, Michael. Ultimate Allocations, British Railways Locomotives 1948 - 1968. Wirral. Michael McManus.