London Underground D78 Stock

The London Underground D Stock is a type of electric multiple unit used on the London Underground District Line (except the Wimbledon-Edgware Road branch). The entire fleet is due to be replaced with S Stock trains in 2015.

History
The stock was ordered in 1976 to replace the pre-war CO/CP Stock and post-war R Stock fleet operating on the District Line. 75 trains were built by Metro-Cammell, entering service on 28 January 1980, with final deliveries in 1983.

Detail
The D Stock is composed of six-car trains, as opposed to the seven-car trains of CO/CP, and R Stock, whose cars were shorter. The traction motors (type LT118) are the same as on the 1973 Tube Stock although bogies are different. The style of the stock train (single leaf doors and transverse and longitude seating) is very similar to that of the 1983 stock that used to operate on the Jubilee line.

D Stock brought many innovations. The rubber coil suspension, for example, meant a smoother ride for passengers. The driver's cab is more ergonomic, the seat being of a swiveling design that allows it to be move forwards, backwards, up or down. The dead man's handle of earlier trains is replaced by a joystick handle which only needs to be twisted for the dead man feature, and moved fore and aft for motoring and braking the train. Additionally, there is a Train Management System (replacing the original Train Equipment Panel) that highlights faults to the driver.

The most noticeable difference between D 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 door buttons were put up around Tube stations in English, French and German when the stock was first introduced. Trains were fitted with a "POGO" switch (Passenger open/Guard's open) which could switch control of the doors from the passengers to the guard (when the trains were first introduced, a guard controlled the doors from the rear cab). While this function proved useful at above-ground stations and termini (especially in the winter months), it did cause a few problems. 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 still remained, until they were removed upon refurbishment between 2005 and 2008.

The D stock windows had to be modified because of overheating in the carriages when new, with pull-down opening windows installed in each car.

Usage and withdrawal
The D stock is currently used only on the District Line. On the Edgware Road branch of the District Line, the platforms of the stations north of High Street Kensington (Notting Hill Gate, Bayswater, Paddington and Edgware Road) are not long enough for the D Stock. As a consequence, the service from Wimbledon-Edgware Road is provided using C Stock. All other branches exclusively use the D stock.

Between April 1985 and May 1987 the D78 stock ran the East London Line service in 3 car formations, there being enough spare D stock because of reduced services on the District Line. This allowed the A stock to be sent off for One Person Operation (OPO) conversion. A60 and A62 stock took over the service again upon return in 1987.

The D78 Stock is scheduled for replacement by the S Stock trains in 2015. However because the stock has been extensively refurbished there may be scope to sell the trains abroad.

In July 2011, Harrogate Chamber of Commerce proposed to use D78 stock on the Harrogate Line in order for this route from York to Leeds via Harrogate to increase capacity.

Stations in the Harrogate and Leeds urban areas are close together; the superior acceleration of D78 stock over the Class 150 diesel multiple units currently used is intended to cut journey times. The line would be electrified with 3rd rail similar to that of the Docklands Light Railway as opposed to the Southern electric network and the Underground.

The District line will be the last Sub-Surface line to receive the S Stock, which is largely due to the recent refurbishment of the D Stock.

Refurbishment
The mid-life refurbishment of the D stock was the first to be carried out under the PPP, by Metronet, and was delayed until contract negotiations were completed. A prototype unit (three cars only) was prepared by London Underground's Train Modification Unit (TMU) at Acton Depot in 2001. This had some differences from the eventual refurbishment detail, but has now been brought up to the standard of the rest of the fleet. The refurbishment programme began in summer 2005 with the first two units coming into service that June. The refurbishment consisted of:


 * applying the LU livery on the outside
 * a restyling of the interiors in green and white
 * maple flooring replaced with rubber
 * adding end-of-car windows
 * new grab bars instead of hanging straps (bobbles on springs)
 * covering over of door buttons
 * dot matrix indicators showing the station and destination on the inside of carriages and on the front and sides of trains
 * audio passenger information system guided by GPS and odometer
 * flip seat/disabled multi purpose area
 * air conditioning to driver's cab
 * anti-vandal paint and window film
 * CCTV



It is the first Underground stock to have electronic side-of-carriage information displays, although some pre-war trains had slot-in or reversible destination or non-stopping plates.

On 15 February 2008, the final remaining "unpainted" train was taken out of service to be refurbished. The train (comprising units 7534 west to 7115 east) was the very last unpainted passenger train on the entire London Underground. Its run could have extended into the weekend, but due to planned weekend engineering works on the District line it was taken out on Friday at the end of operations. The unit left Ealing for its refurbishment on 28 February 2008. Appropriately, the very last silver train on the London Underground ran on the line which first introduced unpainted trains in 1952.

Announcer System
The refurbished stock are fitted with an automated voice announcer (Emma Clarke). An example of the regular voice pattern is as follows:

"This is . Change here for the Piccadilly Line and Circle Line via and . This is a District Line train to ."

Since the fleet was refurbished, it has been the first to have the Digital Voice Announcer to say "Please mind the gap between the train and the platform" at the start of the announcement at each station. For example:

"Please mind the gap between the train and the platform. This is . Change here for the Jubilee Line. Alight here for Westminster Abbey, the Houses of Parliament and riverboat services from Westminster Pier. This is a District Line train to .".

Westbound and eastbound trains at Turnham Green have different announcements depending on the destination of the train (for westbound trains) or where the train has come from (eastbound trains). An example for the westbound is as follows:

"This is . Change here for the District line to . This is a District line train to ."