London Underground Diesel Locomotives - DL81-DL83

DL81-DL83

Three Rolls-Royce-engined diesel-hydraulic locomotives were built in 1967-68, and were supplied to an open-cast iron ore mine at Corby. When the iron ore was worked out, the locomotives were surplus to requirements, and were acquired by London Underground in 1971. They were numbered in the range DL81-DL83. All three were standard 0-6-0DH Sentinel diesel shunters obtained from Thomas Hill (Rotherham) Ltd (the Rolls Royce/Sentinel dealer). They were painted dark green and operated at Neasden and Lillie Bridge depots where they replaced the last of the ex-GWR pannier tank steam locomotives.

The locomotives had a wheelbase of only 9 feet 8 inches (2.95 m), and this was too short to operate the track circuits. Since this made their use impracticable, each was permanently coupled to a tender, which consisted of a bogie removed from a redundant District line Q Stock car. The weight of the bogie was increased to 17 tons, and it was fitted with tripcocks and sleet brushes, so that it could be used for clearing snow and ice from the current rails. Although the tenders were permanently coupled to the locomotives, they carried separate numbers, and were identified as DT81, DT82 and DT83. The tender increased the wheelbase to 28 feet 6 inches (8.69 m).

One locomotive was normally operational at each of the depots, with the third kept as a spare. Transfers between the works occurred when maintenance or repairs were necessary. Movement outside of the depots was severely restricted when the civil engineering department decided that the short wheelbase and 16-ton axle loading might cause overloading problems on a number of bridges. Both the free end (front) of the locomotive and the tender were fitted with 'Ward' type couplers as well as normal buffers and couplings to allow them the couple to almost any Departmental rolling stock (at the time).

Two locomotives have been preserved; no. DL82 on the Mid-Norfolk Railway and no. DL83 on the Nene Valley Railway. The third locomotive, no. DL81, was sold for further use with an industrial user.