Class Image Type Top speed Number operated Notes mph km/h Class 37 Diesel locomotive 90 145 12 Intended to operate sleeper services over non-electrified parts of the railway network in Britain. Eurostar retained three locomotives for the rescue of failed trains, route learning and driver training, but sold them to Direct Rail Services when the new Temple Mills Depot opened in November 2007.[206] Class 73 Electro-diesel locomotive 90 145 2 Were used primarily to rescue failed trains.