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 class 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)
Loco 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
MU working Not fitted
Train heating None
Train brakes None; 15230–15232 Air from 1970
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)
Operators British Railways
Class D3/13, later 3/9, later Class 12
Numbers 15211–15236
Axle load class RA 5
Withdrawn 1968-1971
Preserved 15224 at the Spa Valley Railway
Disposition One currently preserved, remainder scrapped
References: [1]

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.

Withdrawal and Preservation[edit]

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] One, 15222, had been used as a generator by a quarry in South Wales having been acquired from the Newport scrapyard of John Cashmore Ltd. A second, 15231, was sold by BR to Tilling Construction at Grassington. The third, 15224, was sold by BR to the National Coal Board for use in the Kent Coalfield. After use at Betteshanger and Snowdown collieries, it passed into preservation in 1982. It is now the only surviving locomotive of the class, and is now operational and located at the Spa Valley Railway, Royal Tunbridge Wells.

Table of withdrawals[3]
Year Quantity in
service at
start of year
Locomotive numbers
1968 26 4 15213/15/34/36.
1969 22 5 15216/23/26/28/33.
1970 17 3 15217/18/27.
1971 14 14 15211/12/14/19–22/24/25/29–32/35.


  1. ^ Marsden 1981, “SR: 15211-15236”.
  2. ^ Bradley 1975, p. 52.
  3. ^ a b Strickland 1982, p. 63.

Further reading[edit]

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