Originally posted 2017-03-28 14:48:50. Republished by Blog Post Promoter
The London Underground D78 Stock operates on London Underground’s District line, except the Wimbledon to Edgware Road service. Following the withdrawal of the C Stock in June 2014, these are now the oldest subsurface trains in service on the London Underground. The first units were withdrawn in January 2015 with all due to be replaced by S Stock by spring 2017.
The stock consists of six-car trains, as opposed to the seven-car trains of CO/CP and R Stock, whose cars were shorter: under normal operation, each train consists of two 3-car units, and 20 of the units are double-ended to allow 3-car operations under exceptional circumstances. The traction motors are the same LT118 type as on 1973 Tube Stock, but the bogies are different. With single-leaf doors and transverse and longitude seating, the style is very similar to 1983 stock on the Jubilee line.
The stock brought many innovations. The rubber coil suspension meant a smoother ride for passengers. The driver’s cab is more ergonomic, the seat swiveling to move forwards, backwards, up or down. The dead man’s handle is replaced by a joystick that needs to be twisted for the dead man feature, and moved fore and aft for motoring and braking. There is a Train Management System replacing the original Train Equipment Panel that highlights faults to the driver.
The most noticeable difference between the stock and earlier trains is that the doors are single leaf. Originally, passengers pressed door-control buttons to open them. Posters explaining how to operate the doors were put up around Tube stations in English, French and German when the stock was introduced. The stock had a “POGO” switch (Passenger open/Guard’s open) that could switch control of the doors from passengers to the guard (when the stock was introduced, the guard controlled the doors from the rear cab). While this function proved useful at above-ground stations and termini (especially in winter), station dwell time was significantly increased, and passengers had trouble getting used to the new system, not knowing how to open the door. By the late 1990s, the control of the doors went to the driver, but the buttons remained until they were removed on refurbishment between 2004 and 2008.
At over 18 metres (59 ft), the cars are the longest on the Underground. The windows had to be modified because of overheating when new, with pull-down opening windows installed in each car.
by simon schofield