Entered service: 1980
Built by: Metro-Cammell of Birmingham
Lines: District Line (everywhere except between Edgware Road and High Street Kensington)
Length per car: 18.37m (driving motor car), 18.12m (uncoupling non-driving motor car)
Width: 2.85m
Height: 3.62m
Weight: 27.46 tonnes (driving motor car), 26.11 tonnes (uncoupling non-driving motor car), 18.40 tonnes (trailer)
Between 1980 and 1983, 75 six-car D78-Stock trains were introduced to the District Line. Each train comprises two three-car units (a driving motor car, a trailer and either another driving car or a non-driving car).
There are three types of D-Stock car: Driving motor cars are fitted with driving controls and traction motors; uncoupling non-driving motor cars are fitted with traction equipment but no driving controls or accommodation, and have a small cabinet to allow uncoupling and shunting; and finally the trailer coach, which has neither driving or traction controls.
Despite being surface stock, D-Stock is similar to 1973 Tube stock. It has the same size wheels and a similar traction package. Surface stock usually has wheels of 1,067mm in diameter (compared with the 790mm wheels on Tube stock). But D-Stock having the smaller Tube wheels allows more headroom and reduces maintenance costs by lowering the number of different types in use.
Malcolm - 16/01/2015 17:37
No, the smaller wheels DID NOT permit more head room. Floor height is the same as previous "surface" stock with the 1067mm wheels. The article is right however that the motors, gearboxes and wheelsets are virtually the same as the 1973 tube stock. It is S stock where the use of smaller wheels hasxallowed a lower floor andchence more head room, although roof space was taken up by the air conditioning kit. I have to be away by 0925on Friday but can come in at 8.15.ow the smaller wheels