British Rail Class 12

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British Rail Class 12
15224 at Spa Valley Railway, Tunbridge Wells West depot 31 July 2011
Type and origin
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 12 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 12 in (8.98 m)
Width 9 ft 0 in (2.74 m)
Height 12 ft 8 12 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
Generator English Electric 801/7D (DC)
Traction motors English Electric 506A, 2 off
Transmission Diesel electric, double reduction gearing
Multiple working Not fitted
Performance figures
Maximum 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
Operator(s) British Railways
Class D3/13, later 3/9, later Class 12
Number(s) 15211–15236
Axle load class RA 5
Withdrawn 1968-1971
Preserved 15224 at the Spa Valley Railway
Disposition One currently preserved, remainder scrapped

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


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.[2] 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[edit]

The diesel engine is an English Electric 6-cylinder, 4-stroke, 6KT and the traction motors are two 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[edit]

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 for scrap soon afterwards. However, three were sold for industrial use with two of those locomotives being scrapped later on.[3] The only surviving locomotive of the class is 15224, which is operational and located at the Spa Valley Railway, Royal Tunbridge Wells.


  1. ^ Marsden, Colin (1981). "SR: 15211-15236". The diesel shunter: a pictorial record. Oxford: Oxford Publishing Company. ISBN 0-86093-108-0. 
  2. ^ Bradley, D.L. (1975). Locomotives of the Southern Railway. Part 1. Oxford: Railway Correspondence and Travel Society. p. 52. ISBN 0-901115-30-4. 
  3. ^ 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. 

Further reading[edit]

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