British Rail Class 12

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
Specifications Configuration: ​  • Whyte 0-6-0DE  • UIC 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) 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)
Career Operators British Railways Class D3/13, later 3/9, later Class 12 Numbers 15211–15236 Axle load class RA 5 Withdrawn 1968-1971 Preserved 15224 at the Spa Valley Railway Disposition One preserved, remainder scrapped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.

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.

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.

Four (15230–15233) were fitted with air train braking originally for the 1966 Bournemouth line electrification scheme and the need for air brake depot shunters and station pilots; based at Bournemouth 1967 but re-allocated 1968 to Ashford and then often used at Dover shunting continental ferry vans before Classes 08 and 09 were generally converted to this system. They were also utilised as works shunters at Ashford, Brighton and Eastleigh.

The entire class was withdrawn between 1968 and 1971 and most were scrapped 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. It was used at Betteshanger and Snowdown collieries, and was preserved in 1982. It is now the only surviving locomotive of the class, and is awaiting overhaul at the Spa Valley Railway, Royal Tunbridge Wells. A detailed overhaul and restoration scoping plan is in development; the locomotive requires a complete re-wire as the original wiring is suffering age related deterioration. As of January 2021, the project is on hold awaiting suitable funding.

• Bradley, D.L. (1975). Locomotives of the Southern Railway, Part 1. Oxford: Railway Correspondence and Travel Society. ISBN 0-901115-30-4.
• Marsden, Colin (1981). The diesel shunter: a pictorial record. Oxford: Oxford Publishing Company. ISBN 0-86093-108-0.
• Strickland, David C. (September 1983). Locomotive Directory: Every Single One There Has Ever Been. Camberley: Diesel and Electric Group. ISBN 978-0-906375-10-5. OCLC 16601890. OL 27959920M. Wikidata Q105978499.

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