Class 73, no. E6013 (73107) at Rowsley South, on the Peak Railway on 17 April 2003. This locomotive was on loan from Fragonset Railways, and has since returned to main-line service.
Class 73/1 73101 in BR blue livery
The British RailClass 73electro-diesel locomotives are very unusual in that they can operate from a 750 V DC third-rail supply but also have a diesel engine to allow them to operate on non-electrified routes. This makes them very versatile, although the diesel engine produces less power than is available from the third-rail supply so they rarely stray from the former Southern Region of British Rail. Following the withdrawal of the more powerful Class 74 electro-diesels in 1977, the Class 73 is now unique on the British rail system.