The British Rail (BR) Class 13 were created in 1965 because of the need to provide more powerful shunters for the Tinsley Marshalling Yard. This was achieved by permanently coupling together two Class 08 shunters as a 'master and slave' (alternatively 'cow and calf') units, the latter with its cab removed. Both units were ballasted to improve traction. Initially the units were coupled cab-to-cab but it was found more practical to couple master nose to slave cab. A larger, rigid locomotive could not be used because of the risk of grounding on the marshalling yard hump. Three pairs were formed as follows: With the end of hump shunting at Tinsley the class became obsolete. The unique qualities of the locomotives were not required elsewhere and so withdrawal was inevitable; 13002 was withdrawn in 1983, with the remaining two locomotives going with the closure of Tinsley hump in 1985. None of this unusual class survives.