The history of the District line started in 1864 when the Metropolitan District Railway was created to create an underground 'inner circle' connecting London's railway termini. The first part of the line opened using Metropolitan Railway gas-lit wooden carriages hauled by steam locomotives. The District introduced its own trains in 1871 and was soon extended westwards through Earl's Court to Fulham, Richmond, Ealing and Hounslow. After completing the 'inner circle' and reaching Whitechapel in 1884, it was extended to Upminster in East London in 1902. To finance electrification at the beginning of the 20th century, American financier Charles Yerkes took it over and made it part of his Underground Electric Railways Company of London (UERL) group. Electric propulsion was introduced in 1905, and by the end of the year electric multiple units operated all of the services.
On 1 July 1933, the District Railway and the other UERL railways were merged with the Metropolitan Railway and the capital's tramway and bus operators to form the London Passenger Transport Board. In the first half of the 1930s the Piccadilly line took over the Uxbridge and Hounslow branches, although a peak-hour District line service ran on the Hounslow branch until 1964. Kensington (Olympia) has been served by the District line since 1946, and a short branch to South Acton closed in 1959. The trains carried guards until one person operation was introduced in 1985.
The Metropolitan District Railway (commonly known as the District Railway after 1871) was formed in 1864 to build and operate part an underground 'inner circle' connecting London's railway termini.  The first line opened in December 1868 from South Kensington to Westminster, services being operated by the Metropolitan Railway using wooden carriages hauled by steam locomotives. By 1871, when the Metropolitan and District began operating their own trains, the railway had extended to West Brompton and a terminus at Mansion House.  A curve from Earl's Court onto the West London Railway was used by the London & North Western Railway (L&NWR) for a service to Broad Street and the Great Western Railway for a service to Moorgate via Paddington.  Hammersmith was reached from Earl's Court, services were extended to Richmond over the tracks of the London and South Western Railway (L&SWR) and branches reached Ealing Broadway, Hounslow and Wimbledon. As part of the project that completed the Circle line in October 1884, the District began to serve Whitechapel.  Services began running to Upminster in 1902, after a link to the London, Tilbury & Southend Railway (LT&SR) had been built. 
At the start of the 20th century the District was seeing increased competition from the new electric underground tube lines and trams, and the use of steam locomotives underground led to unpopular smoke-filled stations and carriages.  The American Charles Yerkes, who was later to form the Underground Electric Railways of London, financed the needed electrification of the railway and the first electric services ran from Ealing to South Harrow in 1903.  Electric multiple-units were introduced on other services in 1905, and East Ham became the eastern terminus. Electric locomotives were used on the L&NWR services from Mansion House to Earl's Court, and in later years exchanged for a steam locomotive on LT&SR services from Southend to Ealing Broadway at Barking. 
Hounslow and Uxbridge were served by 2 or 3-car shuttles from Mill Hill Park (now Acton Town); some trains also served South Acton and central London in the peaks.  Services were extended again to Barking in 1908 and Upminster in 1932.  In 1932 Piccadilly line trains were extended from Hammersmith to South Harrow, taking over the District service from Acton Town to South Harrow, although the District continued to provide a shuttle from South Harrow to Uxbridge.  In 1933 Piccadilly trains reached to Hounslow West, the District continuing to run services with an off-peak shuttle from South Acton to Hounslow. 
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On 1 July 1933 the District Railway amalgamated with other Underground railways, tramway companies and bus operators to form the London Passenger Transport Board, and from 23 October 1933 Piccadilly line trains ran through to Uxbridge and the District line shuttle withdrawn.  The District line had 173 motor cars that were less than fifteen years old, but these ran with trailer cars that were of the original wooden bodied type built in 1904–05. The 1935–40 New Works Programme saw the replacement of these trailers and the upgrading of motor cars with electro-pneumatic brakes and guard controlled air-operated doors.  The first Q Stock train entered service in November 1938,  trains running in mixed formation with shorter length trains running off-peak.   Some of the older cars with hand-worked doors were retained, becoming known as H Stock.  The off-peak District line services on the Hounslow branch were withdrawn on 29 April 1935 and South Acton served by a shuttle to Acton Town.  In 1932 a double-ended B Stock motor car was adapted to run as a single car, and this was replaced by two G23 Stock cars that had been adapted for One person operation. 
The outbreak of war in 1939 meant the withdrawal of the through Southend services on 1 October 1939, the electric locomotives being later scrapped.  First class accommodation was withdrawn in February 1940.  The London, Midland and Scottish Railway (LMS) had taken over the L&NWR railway's service from Earl's Court and by 1939 this had been cut back to an electric Earl's Court to Willesden Junction shuttle.  Following bombing of the West London Line in 1940 the LMS and the Metropolitan line services over the West London Line were both suspended. This left the Olympia exhibition centre without a railway service, so after the war the Kensington Addison Road station was renamed Kensington (Olympia) and served by a District line shuttle from Earl's Court. 
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London Transport's railways, along with other British railways were nationalised on 1 January 1948.  R Stock, composed of new cars and the Q Stock trailers that had been built in 1938, replaced the trains with hand-operated sliding doors that remained.  The new trains were built between 1949 and 1959,  and after 1952 trains were constructed from aluminium, saving weight. One train was left unpainted as an experiment and considered a success, so between 1963 and 1968 trains were left unpainted or painted white or grey to match.  The transfer of CO/CP Stock from the Metropolitan line in the early 1960s allowed some of the Q stock to be scrapped.  The District line was overcrowded at the east end to Barking and beyond, but it was not possible to run more trains as the tracks were shared with British Rail steam passenger and goods trains to Fenchurch Street. A plan was developed in 1950 to electrify the southerly pairs of tracks with overhead lines for new British Rail trains and separate these from the District line. A flyover and a fly under were built at Barking to allow cross-platform interchange between Underground and British Rail services. British Rail required the District's land at Little Ilford, so a new depot was built at Upminster for District trains.  Work began in 1955, with work on Upminster depot starting the following year. Upminster depot, able to take 34 x 8-car trains, fully opened 1 December 1958, and the work was complete in 1961. British Rail was running a full electric service from June 1962. 
The South Acton shuttle was withdrawn on 28 February 1959, followed by the peak hour District line through service to Hounslow on 9 October 1964.  In the 1970s the Hounslow branch became the Heathrow branch when it was extended to serve Heathrow Airport, first on 19 July 1975 to serve Hatton Cross, and then on 16 December 1977 when Heathrow Central opened.  The whole District line service could not run through Aldgate East as this station was also served by Hammersmith & City trains, so some trains terminated at a bay platform at Mansion House, leaving the line east to Tower Hill overcrowded. Tower Hill station was also cramped, so the station was rebuilt with three platforms on a new site. This opened in 1967 and a year later trains reversed at the new station. 
Services were operated with 6 cars off-peak and 8 cars during peak hours until 1971, when trains were reformed as fixed 7-car trains, and some 6-car trains for the Edgware Road branch.  The CO/CP and R Stock were replaced in the late 1970s by new trains with unpainted aluminium bodies.  A shorter train was needed on the Edgware Road branch due to the platform lengths so more of the C stock units, then already in use on the Circle and Hammersmith and City lines, were built.  The rest of the District line could use longer trains and new D Stock trains were introduced between 1979 and 1983.  One person operation of the trains was proposed in 1972, but due to conflict with the trade unions was not introduced on the District line until 1985. 
Transport for London (TfL) was created in 2000 as part of the Greater London Authority by the Greater London Authority Act 1999.  Control of London Underground passed to TfL in 2003, after the infrastructure of the District line had been partly privatised in a public–private partnership, managed by the Metronet consortium. Metronet went into administration in 2007 and the local government body Transport for London took over responsibilities. 
The Central line is a London Underground line that runs through central London, from Epping, Essex, in the north-east to Ealing Broadway and West Ruislip in west London. Printed in red on the Tube map, the line serves 49 stations over 46 miles (74 km). It is one of only two lines on the Underground network to cross the Greater London boundary, the other being the Metropolitan line. One of London's deep-level railways, Central line trains are smaller than those on British main lines.
The Metropolitan line, colloquially known as the Met, is a London Underground line between Aldgate in the City of London and Amersham and Chesham in Buckinghamshire, with branches to Watford in Hertfordshire and Uxbridge in Hillingdon. Printed in magenta on the tube map, the line is 41.4 miles (66.7 km) in length and serves 34 stations. Between Aldgate and Finchley Road, the track is mostly in shallow "cut and cover" tunnels, apart from short sections at Barbican and Farringdon stations. The rest of the line is above ground, with a loading gauge of a similar size to those on main lines. Just under 67 million passenger journeys were made on the line in 2011/12.
The Circle line is a spiral-shaped London Underground line, running from Hammersmith in the west to Edgware Road and then looping around central London back to Edgware Road. The railway is below ground in the central section and on the loop east of Paddington. Unlike London's deep-level lines, the Circle line tunnels are just below the surface and are of similar size to those on British main lines. Printed in yellow on the Tube map, the 17-mile (27 km) line serves 36 stations, including most of London's main line termini. Almost all of the route, and all the stations, are shared with one or more of the three other sub-surface lines, namely the District, Hammersmith & City and Metropolitan lines. On the Circle and Hammersmith & City lines combined, over 114 million passenger journeys were recorded in 2011/12.
The District line is a London Underground line running from Upminster in the east and Edgware Road in the west to Earl's Court in west London, where it splits into multiple branches. One branch runs to Wimbledon in south-west London and a short branch, with a limited service, only runs for one stop to Kensington (Olympia). The main route continues west from Earl's Court to Turnham Green after which it divides again into two western branches, to Richmond and Ealing Broadway.
The Piccadilly line is a deep-level London Underground line running from the north to the west of London. It has two branches, which split at Acton Town, and serves 53 stations. The line serves Heathrow Airport, and some of its stations are near tourist attractions such as Piccadilly Circus and Buckingham Palace. The District and Metropolitan lines share some sections of track with the Piccadilly line. Printed in dark blue on the Tube map, it is the fourth busiest line on the Underground network, with over 210 million passenger journeys in 2011/12.
Acton Town is a London Underground station in the south-west corner of Acton, West London, in the London Borough of Ealing, close to the border with the London Borough of Hounslow. The station is served by the District and Piccadilly lines and is in Travelcard Zone 3. On the District line, it is between Chiswick Park and Ealing Common stations, and on the Piccadilly line it is between Hammersmith and Ealing Common on the Uxbridge branch & South Ealing on the Heathrow branch. Acton Town station was opened as Mill Hill Park on 1 July 1879 by the District Railway. It remained as a terminus until on 1 May 1883 and 23 June 1903 the DR opened two branches from Acton Town to Hounslow Town and Park Royal & Twyford Abbey respectively. On 4 July 1932 the Piccadilly line was extended to Acton Town. District line services to both the Hounslow and Uxbridge branches were withdrawn completely on 9 and 10 October 1964 after which operations were provided by the Piccadilly line alone.
Upminster is an interchange station serving the town of Upminster in the London Borough of Havering, Greater London. It is on the London, Tilbury and Southend line (LTSR), 15 miles 20 chains (24.5 km) down the line from London Fenchurch Street; it is the eastern terminus of the District line on the London Underground; and it is the eastern terminus of the Romford to Upminster Line on the London Overground network. Upminster is the easternmost station on the London Underground network as well as the easternmost National Rail station in London.
Hounslow West is a London Underground station in locality of Hounslow West in Hounslow within the London Borough of Hounslow, West London. The station is on the Heathrow branch of the Piccadilly line, between Hatton Cross and Hounslow Central stations and is in Travelcard Zone 5. The station is located on Bath Road, close to the Great West Road (A4). The station has an island platform, with step-free access via a stairlift for manual wheelchair users only.
Boston Manor is a London Underground station at the boundary of the boroughs Hounslow and Ealing. The station is situated on the Heathrow branch of the Piccadilly line, between Osterley and Northfields stations, in Travelcard Zone 4.
Hounslow Town was a London Underground station located in Hounslow, west London. It was first opened in 1883 by the District Railway, the precursor to today's District line, on a branch line which is now disused.
London Underground rolling stock includes the electric multiple-unit trains used on the London Underground. These come in two sizes, smaller deep-level tube trains and larger sub-surface trains of a similar size to those on British main lines. New trains are designed for the maximum number of standing passengers and for speed of access to the cars.
The Metropolitan District Railway, also known as the District Railway, was a passenger railway that served London from 1868 to 1933. Established in 1864 to complete an "inner circle" of lines connecting railway termini in London, the first part of the line opened using gas-lit wooden carriages hauled by steam locomotives. The Metropolitan Railway operated all services until the District Railway introduced its own trains in 1871. The railway was soon extended westwards through Earl's Court to Fulham, Richmond, Ealing and Hounslow. After completing the inner circle and reaching Whitechapel in 1884, it was extended to Upminster in Essex in 1902.
The history of the London Underground began in the 19th century with the construction of the Metropolitan Railway, the world's first underground railway. The Metropolitan Railway, which opened in 1863 using gas-lit wooden carriages hauled by steam locomotives, worked with the District Railway to complete London's Circle line in 1884. Both railways expanded, the Metropolitan eventually extending as far as Verney Junction in Buckinghamshire, more than 50 miles (80 km) from Baker Street and the centre of London. The first deep-level tube line, the City and South London Railway, opened in 1890 with electric trains. This was followed by the Waterloo & City Railway in 1898, the Central London Railway in 1900, and the Great Northern and City Railway in 1904. The Underground Electric Railways Company of London (UERL) was established in 1902 to fund the electrification of the District Railway and to complete and operate three tube lines, the Baker Street and Waterloo Railway, the Charing Cross, Euston and Hampstead Railway and the Great Northern, Piccadilly and Brompton Railway, which opened in 1906–07. By 1907 the District and Metropolitan Railways had electrified the underground sections of their lines.
The London Underground R Stock electric multiple units were used on London Underground's District line from 1949 to 1983. Composed of new cars and converted Q38 Stock trailers, the cars were built and converted in three batches between 1949 and 1959. The cars were driving motors (DM) or non-driving motors (NDM), there being no unpowered trailers. The second batch, introduced in 1952, was constructed from aluminium, saving weight and one train was left unpainted as an experiment. Considered a success, trains were left unpainted or painted white or grey to match in 1963–68. Originally designed to operate in trains with six off-peak and eight cars during peak hours, the trains were reformed as fixed seven-car trains in 1971. R Stock trains were replaced by the D78 Stock and withdrawn between 1981 and 1983.
Electric locomotives were first used on the London Underground when the first deep-level tube line, the City and South London Railway (C&SLR), was opened in 1890. The first underground railways in London, the Metropolitan Railway (MR) and the District Railway (DR), used specially built steam locomotives to haul their trains through shallow tunnels which had many ventilation openings to allow steam and smoke to clear from the tunnels. It was impractical to use steam locomotives in the small unvented tubular tunnels of the deep-level lines, and the only options were rope haulage or electric locomotives.
Ealing Common Depot is a London Underground railway depot on the District line, located between Acton Town and Ealing Common stations in west London, England. It is the oldest of the main depots on the Underground, having been built in 1905, when the District Railway was upgraded for electric traction. All depot facilities were moved there from Lillie Bridge Depot, and it was known as Mill Hill Park Works. It subsequently became Ealing Common Works, and its status was reduced to that of a depot in 1922, when Acton Works was opened, and took over responsibility for all major overhauls. Most of the functions of Acton Works were devolved back to the depots, including Ealing Common, in 1985.
London's Metropolitan Railway (MR) amalgamated with other underground railways, tramway companies and bus operators on 1 July 1933, to form the London Passenger Transport Board (LPTB); the MR became the Board's Metropolitan line.
Metropolitan Railway electric multiple units were used on London's Metropolitan Railway after the lines were electrified in the early 20th century.
District Railway electric multiple units were used on London's Metropolitan District Railway after the lines were electrified in the early 20th century.
The London Underground opened in 1863 with gas-lit wooden carriages hauled by steam locomotives. The Metropolitan and District railways both used carriages exclusively until they electrified in the early 20th century. The District railway replaced all its carriages for electric multiple units, whereas the Metropolitan still used carriages on the outer suburban routes where an electric locomotive at the Baker Street end was exchanged for a steam locomotive en route.