A BR design utilising English Electric internal equipment, the 73's were the southern regions electro-diesels and could be powered via the 750v DC third rail or by a EE 600hp diesel engine. The first six, the 73/0's, were built at Eastleigh in 1962 and another forty-three, the 73/1's, were built by English Electric at the Vulcan Foundry between 1965 & 1967. The class spent virtually their entire careers based on the SR working all types of train and are probably remembered best for the Gatwick Express services. A few members of the class are still in use on the mainline with various companies.