|Manufacturer.||73/0: British Railways’ Eastleigh Works and 73/1: English Electric at Vulcan Foundry.|
|Made in.||1962 (test units) and 1975 (regular units).|
|Retired in.||Most were scrapped in 2009. A few are preserved and 1 is used as a Network Rail departmental unit.|
|Weight.||16.36 m (53 ft 8 in)|
|Top speed.||73/0: 80 mph (129 km/h) and 73/1: 90 mph (145 km/h).|
|Length.||16.36 m (53 ft 8 in)|
|Power source.||Electro-diesel with both 660-750v 3rd rail and\or a diesel engine as power sources.|
|Railway\tram track gauge.||4 ft 8 1⁄2 in (1,435 mm) standard gauge.|
|Tractive effort.||73/0 (electric): 42,000 lbf (186.8 kN), 73/0 (diesel): 34,100 lbf (151.7 kN), 73/1 (electric): 40,000 lbf (177.9 kN), 73/1 (diesel): 36,000 lbf (160.1 kN).|
The British Rail Class 73 is a British model of electro-diesel locomotive. The type is unusual in that it can operate from the Southern Region's 650/750 V DC third-rail or an on-board diesel engine to allow it to operate on non-electrified routes. This makes it very versatile, although the diesel engine produces less power than is available from the third-rail supply so the locomotives rarely stray from the former Southern Region of British Rail. Following the withdrawal and scrapping of the more powerful Class 74 electro-diesels in 1977, the Class 73 is now unique on the British railway network. Ten locomotives have been scrapped.
These locomotives were ordered as part of the British Railways 1955 Modernisation plan which included the extension of the Southern Region electrification to various main lines.
They were intended as mixed-traffic locomotives, hauling parcels, freight and also passenger trains, usually on routes that included some non-electrified sections, such as boat trains.
This class of 49 locomotives were built in two batches using English Electric components. The first six locomotives were built by BR at Eastleigh works in 1962 and were numbered E6001-E6006 and classified as type JA. With the introduction of TOPS in 1968 they were to have been classified as Class 72, to differentiate from the later built units. However, instead they became Class 73/0. In the early 1970s the locomotives were renumbered 73001-73006.
The narrow box-like body allowed use of the 73/1 sub-class over the entire the Southern Region network including through the narrow tunnels on the Hastings Line.
Following successful trials of the initial locomotives, a production run of 43 locomotives were built by English Electric at their Vulcan Foundry between 1965 and 1967. They were initially classified as Class JB and numbered E6007-E6049. They differed slightly from the six earlier machines, most notably having an increased tractive effort as well as a higher maximum speed (90 mph as opposed to 80). Following the introduction of TOPS, they became Class 73/1 and were renumbered 73101-73142. One locomotive, E6027, had already been withdrawn following accident damage and so was not renumbered. Further changes were the use of large round Oleo buffers with a pneumatic withdrawal mechanism rather that the traditional coach style (oval) saddle buffer which relied on a pin and spring mechanism. As the JA examples came in for overhaul over the years, the saddle buffers were also replaced making visual identification of the differing machines almost impossible from a distance.
From new, all members of the class were fitted with the Pullman style rubbing plate between the buffers allowing them to close couple with Southern Region electro-pneumatically controlled electric multiple units and diesel electric multiple units for push-pull train operation - the reason for retractable buffers.
The narrow box-like body allowed use all over the Southern Region network including through the narrow tunnels on the Hastings Line.
Gatwick Express subfleet
During 1984, a small subfleet of Class 73s were dedicated to working the upgraded Gatwick Express service, which would feature a Class 73 at the southern end, a rake of air-conditioned Mk2f coaches which had been modified to carry Southern Region multiple unit control jumpers, and a Class 489 "GLV" (themselves converted from former Class 414 driving Motor coaches) at the north end. Both the Class 73 and the GLV provided power, and the trains ran non-stop between London Victoria and Gatwick Airport.
Notable post-privatisation operations
Since privatisation, the Class 73 fleet has been reduced in size following the large-scale withdrawals of the EWS and Gatwick Express fleets. However, many smaller operators have acquired locomotives, so their continued use is assured for the foreseeable future.
Eurostar owns and formerly operated two Class 73 locomotives, which were specially modified to enable them to haul a Eurostar unit. The two locomotives; 73118 and 73130, have additional coupling equipment fitted and were primarily used to rescue failed Eurostar sets, or to haul them over non-electrified routes. They were rarely used away from North Pole depot. When Eurostar moved its operations to the new Temple Mills depot and onto the overhead wiring of High Speed 1 in 2007, the Class 73 locomotives became redundant and were loaned to educational initiatives: 73130 went to RailSchool in East London and 73118 went to Barry Rail Centre in South Wales. Subsequently, when RailSchool failed, 73130 was loaned to the Bluebell Railway but is stored away from the railway.
Merseyrail Electrics had a fleet of four Class 73/0 locomotives (Nos. 73 001, 73 002, 73 004*, 73 005 & 73 006), based at Birkenhead North TMD, for use on shunting and other departmental duties. Two, nos. 73001 and 73006 were repainted into Merseyrail's yellow livery. They were later fitted with sandite discharging equipment and reclassified as Class 73/9. The locomotives were withdrawn from traffic by 2002, and all four were later sold for preservation.
No. 73 004 was used as a source of spare parts and was the first to be cut up.
Network Rail inherited two redundant Gatwick Express locomotives, nos. 73212 and 73213, from its predecessor Railtrack. These were overhauled and painted in the company's blue and green livery. They are used on engineering trains associated with an upgrade of electrical supply systems on the former Southern Region.
A third locomotive, no. 73141, was originally bought for spare parts, but was returned to traffic in case of failure of one of the other two locomotives. The locomotives were later repainted into Network Rail all-over-yellow with red buffer beams.
In 2009, 73141 was acquired by FirstGBRf, with 73212 and 73213 following shortly afterwards.
South West Trains
South West Trains inherited one locomotive, no. 73109, which is used as a "Thunderbird" rescue locomotive. It was named in 1990 to commemorate the 50th anniversary of the Battle of Britain. It is affectionately known as "BoB" by rail enthusiasts.
South West Trains later expanded its fleet, by leasing two more locomotives from Porterbrook, nos. 73201 and 73235. Both are former Gatwick Express locomotives. The first of these, no. 73235, was overhauled in early 2005 and repainted in the new Desiro blue livery. It was joined by no. 73201 later in the same year. Around the same time, no. 73109 was also repainted into the new blue livery. 73109 was acquired by Transmart Trains in 2009. BoB now works with the FirstGBRf rail freight firm as of 2016.
Others worked on at depots, on the Caledonian Sleeper service, for freight services and in maintenance trains until 2012. The class are now mostly in storage, preserved or scrapped.