Despite the fact that diesel locomotives often spend a fair amount of time operating along electrified routes it is unusual that British Rail only ever built two classes of electro-diesel locomotives (these days better known as bi-mode) which could operate both as electric or diesel locomotives, the Class 73 and
Class 74. Both were operated by BR's Southern Region, the Class 73 is the only survivor [1]. A number have been rebuilt and upgraded in the last few years (
Class 73/9) so they look set to remain in service for a long time to come. these will be covered separately.
 |
| GB Railfreight 73 128 leads a class mate through Tonbridge |
| Information |
| Number built: |
49 |
| Built: |
1962, 1965-67 |
| Builder: |
BR Eastleigh / English Electric |
| Motor: |
English Electric 4SRKT Mk II diesel
EE542A or EE546/1B traction motors (750v DC third-rail) |
| Power: |
1, 420 hp (1, 059 kW) - Electric
600hp (447kW) - Diesel |
| Wheel arrangement: |
Bo-Bo |
The Class 73 is an electric locomotive designed to work with SR's 660-750v DC third-rail system. It also has a small diesel engine for operating on non-electrified lines or if the power is off. They are highly versatile locomotives that served on a whole range of traffic in Southern England, being true mixed traffic locomotives they could be found on passenger and freight services.
Their numbers however were reduced in the privatisation era but only ten have been scrapped to date. Twelve have been preserved with the rest still operating on the network most usually employed hauling engineering trains.
| Sub-class |
Details |
| 73/0 |
Original prototype batch, originally to have been called the Class 72 |
| 73/1 |
Main production batch, higher power output and speed |
| 73/2 |
Modified for Gatwick Express push-pull duties
(coupled to the Class 488 and 489) |
| 73/9 |
Re-engineered and upgraded examples |
