||This article needs additional citations for verification. (December 2007)|
|Ridership||260.916 million (2011/12)  passenger journeys|
|Colour on map||Red|
|Line length||74 km (46 mi)|
The Central line is a London Underground line, coloured red on the tube map. It is a deep-level "tube" line, running east-west across London, and, at 76 km (47 mi) it is the longest Underground line. Of the 49 stations served, 20 are below ground. It is considered to be the tube line with the highest point-to-point speeds on the Underground, reaching 70 mph (110 km/h) when the 1992 Stock was introduced. The section between Leyton and Loughton is the part of the London Underground system that has been a railway route the longest, having opened in 1856, seven years ahead of the Metropolitan Railway.
The beginnings 
- For a detailed history of the line, see Central London Railway.
Although the Central London Railway (CLR) was incorporated in 1891 for a line between Shepherd's Bush and Bank, with an extension to Liverpool Street authorised in 1892, the time for completion had to be extended twice, to 1894 and 1899; and it was not until 27 June 1900 that it was formally opened, a month before public traffic began on 30 July to Bank station. The railway was initially operated by electric locomotives hauling trailer cars. The distinctive station buildings, few of which survive, were designed by the architect Harry Bell Measures.
The tunnels were bored with the nominal diameter of 11 feet 8 inches (3.56 m), a diameter also used for several later lines, which was increased on curves but reduced to 11 feet 6 inches (3.51 m) close to the stations. The heavy locomotives caused considerable problems with vibration as they weighed 44 long tons (45 t; 49 short tons), some three-quarters of which was 1⁄4unsprung.
Upon the formation of the London Passenger Transport Board by amalgamation of the CLR with other transport companies in the London area on 1 July 1933, the railway became known as the Central London Line; on 23 August 1937 it was simplified to Central Line.
In the late 1930s the tunnels were expanded and realigned and the stations lengthened. In 1940, the line was converted to the standard tube four-rail electrification. Because of the manner in which the tunnel had been enlarged it was no longer round, and for clearance reasons the positive rail had to be of an unusual shape with the top contact surface 40 mm (1.6 in) higher than normal. This is still the situation, and the extra height can be observed at most deep-level stations, where the insulating 'pots' stand on small cement mounds. Trains between Liverpool Street and White City must have special positive collectors that can lift higher than normal. In turn Central line stock cannot run on any other line, also because they are operated automatically, have no trip-cocks, and would interfere with other signalling equipment. There are also clearance problems with the gearboxes.
The sections under the City were built to follow the streets above rather than run underneath buildings, to take advantage of the free wayleave offered by the government. As a result there are many sharp bends and curves between St Paul's, Bank and Liverpool Street. At Bank, the Central line platforms are so tightly curved it is not possible to see one end of the platform from the other, and the traditional "mind the gap" message is particularly stressed here.
For several years from the outset a uniform fare of 2d (two old pence) was adopted: the railway was popularly known as the "Twopenny Tube". In July 1907 graduated fares of 2d and 3d were introduced: a 1d fare was added in 1909.
Extensions of the line 
- Extended westwards by a loop to Wood Lane Exhibition Station for the Franco-British Exhibition.
- Extended eastwards to Liverpool Street.
- In the west, a short connecting link was made from Wood Lane station to join the Great Western Railway (GWR)-operated line, the Ealing and Shepherd's Bush Railway, allowing trains to run to Ealing Broadway.
- As part of the New Works Programme 1935–40, announced in June 1935, London Transport proposed extensions as follows:
- An extension beyond West Ruislip to Harefield Road and Denham was planned (and shown on tube maps of the period) but was abandoned, along with the Northern Heights extensions of the Northern line, due to post-war establishment of the Metropolitan Green Belt around London, which restricted development of land in the area.
- "to construct a tube railway in continuation of the Central London Line from Liverpool Street eastwards to points where it will connect with the Loughton and Grange Hill lines (probably near Leyton and Newbury Park so as to permit running through trains to stations in the West End of London and beyond without passing over the congested London and North Eastern Railway (LNER) lines at Stratford and Ilford"
- Although the works for the latter were completed by the outbreak of war the opening was delayed, and the section, safer as it was from bombing, was used as a long, narrow, munitions factory by the Plessey company.
- The eastern branch opened in December 1946 as far as Stratford, with trains continuing empty to a temporary reversing facility at Drapers Field, in the cutting south of Leyton), with the line beyond Stratford opening to Woodford and Newbury Park in 1947. On the Fairlop Loop, the southern LNER link from Newbury Park to Ilford closed in 1947, whilst the connection to Seven Kings lasted until 1956. The Newbury Park to Woodford via Hainault section opened to tube trains in 1948, and the section from Woodford to Buckhurst Hill. British Rail (BR) trains continued to access the line via a link from Temple Mills East to Leyton. These included the locomotives and stock for the Epping – Ongar shuttle until electrification in 1957, freight trains to sidings including at Fairlop, Barkingside, Buckhurst Hill, Theydon Bois, South Woodford, Loughton, North Weald, and Ongar) until the mid-1960s, and early-morning and late-night trains between Liverpool Street and Epping, latterly DMUs, last running on 31 May 1970). This section of line now forms a loop and there are through services to Woodford via Hainault.
- For the western extension, a new pair of tracks for the Central line from North Acton to Greenford opened in 1947, with West Ruislip following in 1948. The powers to extend the line to Denham were never used. The GWR halts and stations between Old Oak Common West junction and South Ruislip closed by 1948, with the shuttle to Greenford using a bay in the new Underground station.
- Extended eastwards to Epping, when London Transport took over the line from BR.
- Extended from Epping to Ongar, taking over from BR.
Richmond extensions 
In 1912 plans were published for an extension from Shepherd's Bush under Goldhawk Road, Stamford Brook Road and Bath Road to Turnham Green and Gunnersbury, including stations at Hammersmith Grove, Paddenswick Road, Rylett Road, Stamford Gardens, Turnham Green and Heathfield Terrace. This would have enabled the Central London Railway to run trains through to Richmond and possibly beyond. The route was authorised in 1913 but work had not started by the outbreak of World War I the following year. In 1919 an alternative route was published, building a tunnelled link to the disused London and South Western Railway (L&SWR) tracks south of the L&SWR's Shepherd's Bush station then via Hammersmith (Grove Road) railway station and Turnham Green. Although authorisation was granted in 1920, the connection was never realised, and the L&SWR tracks were used by the Piccadilly line when it was extended west of Hammersmith in 1932. However the proposal has occasionally reappeared.
Epping to Ongar branch 
Although electrification of this section had begun under the 1935/40 New Works Programme (see above), the line remained steam-hauled until 18 November 1957, though on 16–27 June 1952 an experimental ACV/BUT three-car lightweight railcar set operated part of the shuttle service Monday-Friday. Two-, three- and four-car tube trains then worked the branch. Short platforms at North Weald and Blake Hall and limited power supply meant it was not possible to work through trains to and from London, and the line remained a branch, with the shuttle service initially operating from Loughton. Expected levels of patronage use never materialised; the line became a heavy loss maker, and was closed on 30 September 1994 and sold to the Pilot Group. The connection at Epping was lifted soon after closure, but the remaining section of the branch stayed intact.
A heritage passenger service owned by Epping Ongar Railway Ltd started in October 2004. on Sundays from Ongar to Coopersale, stopping at North Weald, with a possible extension to Epping in the future. It does not stop at Blake Hall, as the station platform was removed upon station closure in 1981, and the remaining building is now a private residence.
2003 derailment and closure 
A Central line train derailed at Chancery Lane on 25 January 2003, injuring 32 passengers, after a traction motor fell onto the track. The line was closed while the cause of the failure was determined and appropriate modifications made to the trains. The line was re-opened in stages. By late March 2003 a limited service was running on the eastern and western extremities. Services resumed over the central section on 3 April 2003 and to all stations (at reduced frequency) on 12 April, with full service by the end of the month. The closure also extended to the Waterloo & City line, which uses the same "1992 tube stock" trains, but this line, with only two stops and far fewer trains, reopened quickly.
A more minor derailment occurred on a set of points at the London end of the westbound platform at White City on 11 May 2004, but there were no reported injuries. At that time the line was shut between Marble Arch and North Acton while the cause of the failure was investigated.
2007 derailment 
Three carriages derailed on the westbound line between Mile End and Bethnal Green at about 0900 BST on 5 July 2007. The cause was attributed to a roll of tarpaulin from a storage location next to the lines. The London Fire Brigade sent 14 fire engines to the scene, including four urban search and rescue vehicles. The line was closed between Liverpool Street and Leytonstone and re-opened on 7 July 2007.
2012 object striking 
On 31 October 2012 a Central line train struck a trackside object near Holland Park. This caused very severe delays on the line and it was closed between Marble Arch and White City. The accident happened on an early-morning service but 200 people still had to be rescued.
Rolling stock 
Former rolling stock 
When opened in 1900, the railway was operated by electric locomotives hauling cars. The cars had gates at each end, similar to those on the City and South London Railway and the Glasgow Subway. With a large unsprung weight, the locomotives proved highly unsatisfactory and the cause of considerable vibration. They were replaced as early as 1903 with motor cars, with the existing cars being adapted to run as trailers in newly-formed electric multiple units.
By the 1920s the rolling stock was in need of modernisation or replacement. Since the then-new Standard Stock was too large to work in the line's tunnels, it was decided to modernise the existing fleet. The end gates were removed and replaced by an extension to the passenger accommodation. Two air-operated single-leaf sliding doors were inserted into each side of each car. Additional trains were purchased for the opening of the Wood Lane to Ealing Broadway extension in 1920. These were also temporarily used on the Watford extension of the Bakerloo line.
The 1900/03 stock and 1920 stock were finally withdrawn from service in 1939. With the enlargement of the tunnels and modification of the electrical supply, Standard Stock (displaced from the Northern line by new 1938 Stock) was operated, eventually as 8-car trains following platform extensions.
The Standard Stock became increasingly unreliable during the 1950s. Some had been stored during World War II pending the opening of extensions. Plans for replacement, using a production version of the prototype 1960 Stock, were abandoned; new trains of 1962 Stock, virtually identical to the tried and tested 1959 Stock, were ordered instead. These operated until their replacement by 1992 Stock in the early 1990s.
The Epping-Ongar branch was not electrified until 1957, prior to which the service was operated by BR using steam-hauled coaches. Upon electrification, two-car sets of 1935 Stock were initially used, later replaced by four-car sets of 1962 Stock specially modified to cope with the limited current. The section closed in 1994, and is now the Epping Ongar Railway.
The 1967 rolling stock used on the Victoria line was also used on the Hainault-Woodford section until 1984. This was made possible because this section was converted to automatic operation as a trial for the Victoria Line.
Current trains 
In common with virtually all other Underground lines, the Central line is worked by a single type of rolling stock. The 1992 Tube Stock was introduced gradually from April 1993 to 17 February 1995, and were the first of their type in London to have automated announcements for connections and station stops. Although like the Jubilee's 1996 stock trains the next station announcements were not used until the ATP was in place. The stock is painted in the standard red, white and blue Underground livery and runs in eight-car sets.
In 1996 the line was fitted with Automatic Train Protection, and subsequently full ATO (Automatic Train Operation) was brought into use during service in sections between 1999 and 2003.
In August 2011, the seats were given a refresh; the moquette being replaced with a new Underground-wide design. Additionally, window frames were modified to enable their removal for emergency repairs, and the interior lighting surrounds were deep-cleaned. All refresh work was completed ahead of the London 2012 Olympics.[dated info]
The TfL line diagram is available online.
In order from west to east.
||Terminus Opened as West Ruislip (for Ickenham); the suffix was later dropped.|
|Ealing Broadway ( Trains to Heathrow)||
||Terminus – Change for District line|
||Trains run right-handed through this station|
||Refurbished in 2008|
|Notting Hill Gate||
||Change for Circle and District lines|
||Opened as Queens Road; renamed 1 September 1946|
||Change for Jubilee line|
||Change for Bakerloo and Victoria lines|
|Tottenham Court Road||
||Opened as Oxford Street; renamed 9 March 1908 – Change for Northern line|
||Opened as a Piccadilly station on 15 December 1906. Central line platforms opened 25 September 1933 and station renamed Holborn (Kingsway); the suffix was later dropped. Change for Piccadilly line.|
||Renamed Chancery Lane (Grays Inn) 25 June 1934; the suffix was later dropped|
||Opened as Post Office; renamed 1 February 1937|
||Change for Circle, District, Northern and Waterloo & City lines and DLR|
|Liverpool Street ( Trains to Stansted)||
||Change for Jubilee line, London Overground, DLR and Greater Anglia train services (towards Shenfield, Tottenham Hale and London Liverpool Street)|
||Opened as South Woodford (George Lane); renamed 1947|
||Terminus of Hainault Loop|
||Currently least used station on the network|
Former stations 
- Denham; never connected
- Harefield Road; never opened
- Wood Lane; closed 22 November 1947
- British Museum; 24 September 1933
- North Weald; first served 25 September 1949; closed 30 September 1994.
- Blake Hall; first served 25 September 1949; closed: 31 October 1981.
- Ongar; first served 25 September 1949; closed 30 September 1994.
There are three depots: West Ruislip (), Hainault ( ) and White City ( ).
Future plans 
The proposed Crossrail 2 line, running from south to northeast London and due to open by 2030, was planned for a number of years to be taking over the Epping branch between Leytonstone and Epping. The section between Leytonstone and Woodford via Hainault would have become the main line, and trains that would have terminated at Epping would have run to Woodford via Hainault. However, as of 2013 the preferred route options for the line no longer include this proposal.
When the London Overground East London line was extended between 2008 and 2010 a new Shoreditch High Street station opened. The Central line runs directly below the station and it has long been proposed to provide an interchange. The station would lie between Liverpool Street and Bethnal Green, which is one of the longest gaps between stations in central London. Although there would be many benefits to this interchange, it was ruled out on grounds of the disruption it would cause to the Central line while being built, creating high levels of overcrowding and heavily increasing journey times. TfL has since stated that the proposal will be revisited and it could be made possible once Crossrail has been completed in 2018.
The Central line was the first Underground line to receive a complete refurbishment in the early 1990s, including the introduction of new rolling stock. Once the last line to be fully upgraded, the Bakerloo line, is completed in 2018, it is planned that new trains will start to be introduced on the Central line. TfL has started working with train manufacturers to develop a concept train to run not only on the Central line but also the Bakerloo, Piccadilly and Waterloo & City lines (which will receive new rolling stock before the Central line).
The London Borough of Hillingdon is planning to lobby TfL to extend the line to Uxbridge, linking the Central line to the Metropolitan and Picadilly lines near Ruislip depot. TfL has stated that the link would become viable only when the Metropolitan line's signalling is upgraded near 2017.
The developers of the First Central business park at Park Royal, west London, were planning a new station between North Acton and Hanger Lane. This would have served the business park and provide a walking distance interchange with Park Royal station on the Piccadilly line. This is not being actively pursued; London Underground has said that the transport benefits of a Park Royal station on the Central line are not sufficiently high to justify the costs of construction.
- "LU Performance Data Almanac". Transport for London. 2011/12. Retrieved 1 August 2012.
- "London Underground Key Facts". Transport for London. Retrieved 21 May 2008.
- Day, John R.; Reed, John (2008) . The Story of London's Underground (10th ed.). Harrow: Capital Transport. pp. 53, 57. ISBN 978-1-85414-316-7.
- Lee, Charles Edward (May 1970). Seventy Years of the Central. Westminster: London Transport. p. 27. ISBN 0-85329-013-X. 570/1111/RP/5M.
- The London Gazette: . 26 November 1912.
- Central London Railway Act, 1913
- The London Gazette: . 25 November 1919.
- The London Gazette: . 6 August 1920. Retrieved 6 April 2010.
- "Central line facts". Transport for London. Retrieved 30 June 2008.
- "Bakerloo from Queen's Park to Ealing and Central Line from Shepherd's Bush to Richmond". Transport Plans for the London Area. 14 June 1999. Archived from the original on 19 January 2008. Retrieved 30 June 2008.
- "Tube route safety checks ordered". BBC News. 5 July 2007.
- Rawlinson, Kevin (31 October 2012). "Central Line passengers stuck in Tube tunnel after train strikes object 'that fell from engineering train'". The Independent (London). Retrieved 2 November 2012.
- Hardy, Brian (2002) . London Underground Rolling Stock (15th ed.). Harrow Weald: Capital Transport. p. 10. ISBN 1-85414-263-1.
- Bruce, J. Graeme; Croome, Desmond F. (2006) . The Central Line: An Illustrated History. Capital Transport. p. 69. ISBN 1-85414-297-6.
- TFL line diagram
- Rose, Douglas (1999). The London Underground, A Diagrammatic History. London: Douglas Rose/Capital Transport. ISBN 1-85414-219-4. OCLC 59556887.
- Crossrail official site.
- Route options
- "Chelsea-Hackney line". Crossrail. No date. Retrieved 11 April 2012.
- "Crossrail 2: Supporting London's Growth" (PDF). London First. February 2013. Retrieved 2013-02-18.
- "Tube upgrade plan: Central line". Transport for London. No date. Retrieved 11 April 2012.
- Waboso, David (December 2010). "Transforming the tube". Modern Railways (London). p. 44.
- "Siemens reveals innovative air-con for deep Tube trains". Rail (673) (Peterborough). 29 June 2011. p. 12.
- Coombs, Dan (17 June 2011). "'Extending Central Line to Uxbridge will cut traffic'". Uxbridge Gazette.
- First Central Business Park.
- "Proposed Park Royal Central Line station". 20 October 2009. Retrieved 21 May 2012.
- Central line – London Underground page with line facts and brief history
- Clive's Underground Line Guide
- A History of the London Tube Maps – 1914 tube map showing proposed extension to Gunnersbury
- Epping Ongar Railway – The company currently owning the Epping and Ongar branch and running trains on it.