What is British Rail Class 73?
{{Infobox Locomotive |name = British Rail Class 73 |powertype = Electro-diesel |image = 73201 at Woking.jpg |caption = Class 73, no. 73201 at [[Woking]]. This locomotive was used by [[South West Trains]] as a “Thunderbird” to rescue failed trains.<ref>It's now at Long Marston</ref> |builder = ''73/0:'' [[British Railways]]’ [[Eastleigh Works]]<br>''73/1:'' [[English Electric]] at [[Vulcan Foundry]] |builddate = 1962, 1965–1967 |totalproduction = 49 |gauge = {{RailGauge|ussg|lk=on|al=on}} |primemover = [[English Electric]] 4SRKT Mk II |generator = |tractionmotors = ''73/0:'' EE 542A<br>''73/1:'' EE 546/1B |whytetype = [[Bo-Bo]] |uicclass = Bo'Bo' |wheeldiameter = {{convert|3|ft|4|in|m|3|abbr=on}} |trainbrakes = Vacuum, Air and Electro-Pneumatic |locobrakeforce = |length = 16.36 m (53 ft 8 in) |width = |height = |locoweight = ''73/0:'' {{convert|76.30|LT|lk=on}}<br>''73/1:'' {{convert|76.80|LT|lk=on}} |electricsystem = 660–750 [[Volt|V]] [[Direct current|DC]] |collectionmethod = Third rail |topspeed = ''73/0:'' {{convert|80|mph|km/h|0|abbr=on}}<br>''73/1:'' {{convert|90|mph|km/h|0|abbr=on}} |poweroutput = ''Electric (continuous):'' {{convert|1420|hp|0|abbr=on|lk=on}}<br>''Electric (one-hour):'' {{convert|1600|hp|0|abbr=on}}<br>''Engine:'' {{convert|600|hp|0|abbr=on}} |tractiveeffort = ''73/0 (electric)'': {{convert|42000|lbf|kN|1|abbr=on|lk=on}}<br>''73/0 (diesel):'' {{convert|34100|lbf|kN|1|abbr=on}}<br>''71/0 (electric):'' {{convert|40000|lbf|kN|1|abbr=on}}<br>''73/1 (diesel):'' {{convert|36000|lbf|kN|1|abbr=on}} |fuelcap = |trainheating = [[Electric Train Heating]] |axleloadclass = [[Route availability]] 6 |railroad = [[British Rail]]<br />[[Eurostar]]<br />[[FM Rail]]<br />[[Gatwick Express]]<br />[[FirstGBRf]]<br />[[Network Rail]]<br />[[South West Trains]] |roadnumber = E6001–E6049; later 73001–73006, 73101–73142 }} [[Image:E6013 at Rowsley South.jpg|thumb|right|Class 73, no. E6013 (73107) at Rowsley South, on the [[Peak Rail]]way on 17 April 2003. This locomotive was on loan from