The locomotives had a wheelbase of only , 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 .