British Rail Class 12
|British Rail Class 12|
15224 at Spa Valley Railway, Tunbridge Wells West depot 31 July, 2011
|Builder||British Railways Ashford Works|
|Order number||SR 3413 (15), 3537 (11)|
|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; 53.8 short tons)|
|Fuel capacity||660 imp gal (3,000 l; 790 US gal)|
|Prime mover||English Electric 6KT|
|Traction motors||English Electric 506A, 2 off|
|Transmission||Diesel electric, 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 brakes||None; 15230–15232 Air from 1970|
|Axle load class||RA 5|
|Preserved||15224 at the Spa Valley Railway|
|Disposition||One currently preserved, remainder scrapped|
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 BFB 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.
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.
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.
The entire class was withdrawn between 1968 and 1971 and most were cut up soon afterwards but three were sold for industrial use. The only surviving locomotive of the class is 15224, which is operational and located at the Spa Valley Railway, Royal Tunbridge Wells.
- Marsden, Colin (1981). "SR: 15211-15236". The diesel shunter: a pictorial record. Oxford: Oxford Publishing Company. ISBN 0-86093-108-0.
- Bradley, D.L. (1975). Locomotives of the Southern Railway. Part 1. Oxford: Railway Correspondence and Travel Society. p. 52. ISBN 0-901115-30-4.
- Strickland, D.C. (1982). Locomotive directory: every single one there has ever been. Camberley: Diesel and Electric Group. p. 63. ISBN 0-906375-10-X.
- McManus, Michael. Ultimate Allocations, British Railways Locomotives 1948 - 1968. Wirral. Michael McManus.