British Rail Class 13

The British Rail Class 13 was a type of diesel-electric shunting locomotive. The type was designed in 1965 because of the need to provide more powerful shunters for the Tinsley Marshalling Yard. Due to Tinsley's status as a hump yard, it was not possible to use a single locomotive owing to the risk of grounding. So, to achieve the required power, a pair of shunters were permanently coupled in 'master and slave' formation, with the slave unit having had its cab removed. Both units were then ballasted to improve traction. Initially coupled cab-to-cab, it was found more practical to couple master nose to slave cab.

Units
Three pairs were formed as follows:

Withdrawal
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 The unique qualities of the locomotives were not required elsewhere and so withdrawal was inevitable; 13 002 was withdrawn in 1981, with the remaining two locomotives going with the closure of Tinsley hump in 1985. None of this unusual class survives.