The London Underground

London Underground

The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

 D Stock is a type of electric multiple unit

Electric multiple unit

An electric multiple unit or EMU is a multiple unit train consisting of self-propelled carriages, using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number of the carriages...

 used on the London Underground

London Underground

The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

 District Line

District Line

The District line is a line of the London Underground, coloured green on the Tube map. It is a "sub-surface" line, running through the central area in shallow cut-and-cover tunnels. It is the busiest of the sub-surface lines. Out of the 60 stations served, 25 are underground...

 (except the Wimbledon-Edgware Road branch). The entire fleet is due to be replaced with S Stock

London Underground S Stock

The S Stock is a class of sub-surface train currently being delivered by Bombardier Transportation in Derby to the London Underground to replace 177 existing trains on the Metropolitan, District, Hammersmith & City, and Circle lines, with a new fleet of standardised car design, totalling 191 trains...

 trains in 2015.
The stock was ordered in 1976 to replace the pre-war CO

London Underground O Stock

The O and P Stock was built for the Metropolitan Line and Hammersmith & City Line in 1937–1940 by Gloucester RC&W and Birmingham RC&W. In all there were 262 driving motors and 103 trailers...

/CP Stock

London Underground O Stock

The O and P Stock was built for the Metropolitan Line and Hammersmith & City Line in 1937–1940 by Gloucester RC&W and Birmingham RC&W. In all there were 262 driving motors and 103 trailers...

 and post-war R Stock

London Underground R Stock

The R38, R47, R49, and R59 Stock cars were built for the District Line in 1938, 1949, 1952 and 1959. R Stock cars were driving motors and non-driving motors...

 fleet operating on the District Line

District Line

The District line is a line of the London Underground, coloured green on the Tube map. It is a "sub-surface" line, running through the central area in shallow cut-and-cover tunnels. It is the busiest of the sub-surface lines. Out of the 60 stations served, 25 are underground...

. 75 trains were built by Metro-Cammell, entering service on 28 January 1980, with final deliveries in 1983.
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.