Class 71 (BR Doncaster / English Electric 2,552hp DC Electric Type HA)

The Class 71 DC electric locomotive was built for the expansion of the Southern Region third-rail DC network into Kent. They were designed with an emphasis on a good power/weight ratio [1] with inspiration taken from best practice on the continent.

Number built: 24
Built: 1958-60
Builder: BR Doncaster / English Electric
Engine: 4 EE432/A traction motors (750/650v DC third rail, 650v DC OHLE)
English Electric 836 DC booster
Power: 2, 552 hp (1, 900 kW) (maximum)
2, 300 hp (1, 720 kW) (continuous)
Wheel arrangement: Bo-Bo

The Class 71 (originally known as HA in the Southern Region's pre-TOPS classification scheme) operated off DC third rail. However the Class 71 was also equipped with a pantograph for use in yards such as Hither Green which had light-weight tram style DC overhead catenary as this was considered safer for staff walking about the yard than live rails [2]. The Class 71 worked boat trains, prestigeous expresses like the Golden Arrow and freights.

The Class 71 was equipped with a flywheel booster to handle gaps in the electric supply and could travel for short distances "off juice". However the Class 71's role was reduced as the sort of trains it was intended for were withdrawn or switched to multiple-units and using diesel or electro-diesel traction was more flexible. They had to be carefully diagrammed so they only worked yards and routes which had been electrified, an extra problem at night time and at weekends was where the power was turned off due to engineering work necessitating lengthy detours or replacement by diesel locomotives.

Withdrawals began in the 1960s with 10 removed from service to be converted into the Class 74 electro-diesel. The bulk of the fleet was laid up in late 1976 and withdrawn in 1977 [3]. One has been preserved.
71 001 preserved at NRM Shildon

[1] Brian Haresnape, Electric Locomotives (Ian Allan, 1983) p. 41
[2] Alan Williams, Southern Electric Album (Ian Allan, 1977) p. 90
[3] Pip Dunn, British Rail Main Line Locomotive Specification Guide (Crowood Press, 2013) p. 145