British Rail Class 74

British Rail Class 74

74 003 in BR blue with full yellow ends

Type and origin Power type Electro-diesel Builder British Railways' Doncaster Works; rebuilt BR Crewe Works Build date 1958–1960; Rebuilt 1967–1968 Total produced 10 (rebuilt)

Specifications Configuration Bo-Bo AAR wheel arr. B-B UIC class Bo'Bo' Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Wheel diameter 4 ft 0 in (1.219 m) Loco weight 77 long tons (78 t; 86 short tons) Electric system(s) 650–750 V Direct Current Third rail Current collection Contact shoe Prime mover Paxman 6YJXL Traction motors English Electric 532A, 4 off Train heating Electric Train Heating Train brakes Vacuum, Air, Electro-Pneumatic

Performance figures Power output Electric (continuous): 2,300 hp (1,715 kW) Electric (one-hour): 2,552 hp (1,903 kW) Engine: 650 bhp (485 kW) Tractive effort Electric: 47,500 lbf (211.3 kN) Diesel: 40,000 lbf (177.9 kN)

Career Operators British Railways’ Southern Region Numbers E6101–E6110 Axle load class Route availability 7 Disposition All scrapped

British Rail Class 74 was an electro-diesel locomotive that operated on the Southern Region of British Railways, rebuilt from redundant Class 71 locomotives in the late 1960s. An electro-diesel locomotive is one that can operate either from an electrical supply, such as overhead catenary or (in this case) an energised third rail, or from an onboard diesel engine. All the locomotives were withdrawn between June 1976 and December 1977; they were scrapped between 1977 and 1981.

Twenty-four examples of British Rail Class 71 (pre-TOPS type HA) were built in 1958 at the British Rail works in Doncaster and in 1964 ten were deemed surplus to requirements, withdrawn from service and placed in storage. The Southern Region was highly impressed with the "little-ED" JA & JB/class 73 locomotives and were keen to see a higher power locomotive with the same flexibility. In 1965, discussions were opened with English Electric (builders of the production JB/Class 73) to produce a high powered electro-diesel. Originally a centre-cab locomotive was envisaged similar in concept to the Clayton Class 17 but details on this are scant. This design was not pursued - possibly due to the historical frugality of the SR and the availability of the ten moth-balled members of Class 71. The work to convert these to electro-diesels was originally to have taken place at the Southern Region works at Eastleigh, but their involvement in new build EMUs for the Bournemouth electrification meant that Crewe was chosen for the rebuilds. The redundant HA locomotives were moved in groups to Crewe where they were rebuilt into type HB/Class 74 electro-diesels. Buckeye couplers and high-level control & brake jumpers were fitted to facilitate working with other EP stock - especially TC units in push-pull mode. Also, two-tone "raspberry" air horns were mounted on the cab roof, replacing the original air whistle of Class 71 locomotives.