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 has the greatest total length of track of any line on the Underground. Out of the 49 stations served, 20 are below ground. It is the second busiest line on the Underground.

History

The beginnings

Although the Central London Railway 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 (1894, 1899); and it was not until June 27, 1900 that it was formally opened, a month before public traffic began to use the railway on July 30, to Bank station. The railway was initially operated by electric locomotives hauling a train of trailer cars. The distinctive station buildings, many of which survive, were designed by the architect Harry Bell Measures.

The railway has had a chequered history. Although the tunnels were bored with the unusual diameter of 11 feet 8¼ inches (3.56m), they were not well aligned and it was discovered that the rolling stock, which was already smaller than would be expected for this size of tunnel, would not fit. It is rumoured that the engineers forgot to take into account the height of the rails above the tunnel floor. The problem was remedied by a combination of replacing the bullhead rail running rails with lower profile bridge rails, and shortening the springs on the rolling stock. The locomotives caused considerable problems with vibration as they weighed 48 long tons (49 tonnes), most of which was unsprung.

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 tunnel had been enlarged, it was no longer round and for clearance reasons the positive rail within the original tunnels had to be of an unusual shape with the top contact surface 40 mm (1½ inches) higher than normal. This is still the situation today, 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 the current Central line stock cannot run on any other line, partly because they are operated by Automatic Train Operation, have no trip-cocks, and would interfere with other signalling equipment. There are also clearance problems with the gearboxes.

One legacy of the line's building is that the sections under the City were built to follow the geography of the streets above, rather than 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 station, 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 two pence was adopted: the railway was popularly known as the "Twopenny Tube". In July 1907 graduated fares of two pence and three pence were introduced: a one penny fare was added in 1909.

Extensions of the line

1908:

Extended in the west by means of a loop to Wood Lane Exhibition Station in 1908 for the Franco-British Exhibition.

1912: Extended eastwards to Liverpool Street.

1920: 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.

1935: As part of the New Works Programme 1935–40, announced in June 1935, London Transport proposed works to extend the Central line as follows:

* "to construct and electrify two additional GWR tracks from North Acton to Ruislip, allowing Central line trains from Wood Lane to use the line;

:An extension beyond West Ruislip to Harefield Road and Denham was also 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 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 LNER (London and North Eastern Railway) lines at Stratford and Ilford"

WW2: Although the works of 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.

1946-48: The eastern branch opened in December 1946 as far as Stratford (with trains continuing empty through the new tube tunnels to a temporary reversing facility at Drapers Field, in the cutting south of Leyton), with the line beyond Stratford opening as far as Woodford and Newbury Park in 1947. As for the Fairlop Loop, the southern 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, as did the section from Woodford to Buckhurst Hill. BR trains continued to access the line via a link from Temple Mills East to Leyton. These included the BR locomotives and stock for the Epping - Ongar shuttle (until electrification in 1957), freight trains to sidings (including 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 formed by DMUs, and last running on May 31, 1970). This section of line now forms a loop and there are some through services to Woodford via Hainault (and vice versa), every 20 minutes or so.

For the western extension, a new pair of tracks for the Central line opened from North Acton to Greenford opened in 1947, with the section to West Ruislip following in 1948. The powers to extend the line to Denham were never implemented. The Great Western Railway's halts and stations between Old Oak Common West junction and South Ruislip were all closed by 1948, with the shuttle to Greenford using a bay in the new Underground station.

1949: Extended to Epping, when London Transport took over the line from British Railways.

1957: Extended from Epping to Ongar, taking over from British Railways.

Richmond extensions

In 1912 plans were published for an extension of the line 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 1913Central London Railway Act, 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 station and Turnham Green. Although authorisation was granted in 1920,Central London and Metropolitan District Railway Companies (Works) Act, 1920 the connection was never realised, and the L&SWR tracks were eventually 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 (though from 16-27 June 1952 an experimental ACV/BUT three-car lightweight railcar set operated part of the shuttle service Monday-Friday) until November 18, 1957. From that date two-, three- and four-car tube trains were used on the branch. Shorter platforms at North Weald and Blake Hall, coupled with a limited power supply, meant it was not possible to work through trains to and from London, and the line remained a branch, though the shuttle service initially operated between Ongar and Loughton. Expected levels of passenger use never materialised; the line became a heavy loss maker, and was closed on September 30, 1994 and sold to the Pilot Group. The direct connection to 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 operation in October 2004. A train runs on Sundays from Ongar to Coopersale, stopping at North Weald, with a possible extension to Epping in the future. It does not stop at the old Blake Hall station, as the station platform was removed upon station closure in 1981.

2003 derailment and closure

A Central line train derailed at Chancery Lane on January 25, 2003, injuring 32 passengers, after a traction motor became detached from the train and fell onto the track. The entire line was closed whilst the cause of the failure was determined and appropriate modifications made to the trains. The line was then re-opened in stages. By late March 2003 a limited service was running on the eastern and western extremities of the line, with the central section still closed. Services resumed over that central section on April 3, 2003 and to all stations (albeit at a reduced frequency) on April 12, with a full service by the end of the month. The initial closure also extended to the Waterloo & City line which uses the same "1992 tube stock" trains, but this line, being far shorter - 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 May 11, 2004, but there were no reported injuries.

2007 derailment

Three carriages came off the rails on the westbound Central line between Mile End and Bethnal Green at about 0900 BST on July 5, 2007. The cause was attributed to a roll of tarpaulin which came free from a storage location next to the lines.

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 July 7, 2007.

Rolling stock

Former rolling stock

When opened in 1900, the railway was operated by electric locomotives hauling coaches. The coaches were fitted with gates at each end, similar to those used on the City and South London Railway and the Glasgow Subway. The locomotives, with a large unsprung weight, proved highly unsatisafactory and the cause of considerable vibration. They were replaced as early as 1903 with motor cars, with the existing coaching stock being adapted to run as trailers within newly formed electric multiple units.

By the 1920s the rolling stock was in need of modernisation or replacement. Given that 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 both sides of each carriage. Reconstruction work was carried out by the Union Construction Company at Feltham.

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 on behalf of London Transport by British Railways using steam hauled coaches. Upon electrification, two-car sets of 1935 Stock were initially used, later replaced by 4-car sets of 1962 Stock specially modified to cope with the limited current. The section closed in 1994, and eventually became a heritage railway now known as the Epping Ongar Railway.

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 February 17, 1995, and was the first in London to introduce automated announcement of the next station and connections available. The 1992 stock is painted in the standard red, white and blue Underground livery and runs in 8-car sets.

In 1996 the line was fitted with Automatic Train Operation, and this was brought into service in sections over the next few years.

Map

The TFL line diagram is available online.

Stations

In order from west to east.

West Ruislip Branch
Station	Image	Opened	Additional Information
West Ruislip		November 21, 1948	Terminus Opened as West Ruislip (for Ickenham); the suffix was later dropped.
Ruislip Gardens		November 21, 1948
South Ruislip		November 21, 1948
Northolt		November 21, 1948
Greenford		June 30, 1947
Perivale		June 30, 1947
Hanger Lane		June 30, 1947
Branch joins Central Branch at North Acton
Ealing Broadway Branch
Ealing Broadway ( Trains to Heathrow)		August 3, 1920	Terminus
West Acton		November 5, 1923
Branch joins Central Branch at North Acton
Central section
North Acton		November 5, 1923
East Acton		August 3, 1920
White City		November 23, 1947
Shepherd's Bush		July 30, 1900	Refurbished in 2008
Holland Park		July 30, 1900
Notting Hill Gate		July 30, 1900
Queensway		July 30, 1900	Opened as Queens Road; renamed September 1, 1946
Lancaster Gate		July 30, 1900
Marble Arch		July 30, 1900
Bond Street		September 24, 1900
Oxford Circus		July 30, 1900
Tottenham Court Road	[[Image:Tottenham Court Road stn main entrance	July 30, 1900	Opened as Oxford Street; renamed March 9, 1908
Holborn		September 25, 1933	Opened as Holborn (Kingsway); the suffix was later dropped. Opened as a Piccadilly station on December 15 1906, but Central platforms opened September 25, 1933
Chancery Lane		July 30, 1900	Renamed Chancery Lane (Grays Inn) June 25, 1934; the suffix was later dropped
St. Paul's		July 30, 1900	Opened as Post Office; renamed February 1, 1937
Bank		July 30, 1900
Liverpool Street ( Trains to Stansted)		July 28, 1912
Bethnal Green		December 4, 1946
Mile End		December 4, 1946
Stratford		December 4, 1946
Leyton		May 5, 1947
Leytonstone		May 5, 1947
Central Branch splits into Epping and Hainault Loop Branches
Epping Branch
Snaresbrook		December 14, 1947
South Woodford		December 14, 1947	Opened as South Woodford (George Lane); renamed 1947
Woodford		December 14, 1947	Terminus of Hainault Loop
Buckhurst Hill		November 21, 1948
Loughton		November 21, 1948
Debden		September 25, 1949
Theydon Bois		September 25, 1949
Epping ,		September 25, 1949	Terminus
Hainault Loop
Wanstead		December 14, 1947
Redbridge		December 14, 1947
Gants Hill		December 14, 1947
Newbury Park		December 14, 1947
Barkingside		May 31, 1948
Fairlop		May 31, 1948
Hainault		May 31, 1948
Grange Hill		November 21, 1948
Chigwell		November 21, 1948
Roding Valley		November 21, 1948	Currently least used station on the network
Trains join Epping Branch at Woodford and 'Terminate (except peak hours)

Former Stations

• Denham (never connected)
• Harefield Road (never opened)
• Wood Lane (closed 1947)
• British Museum (closed 1933)
• North Weald first served September 25, 1949; closed September 30, 1994.
• Blake Hall first served September 25, 1949; closed: October 31, 1981.
• Ongar first served September 25, 1949; closed September 30, 1994.

Future plans

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 currently being actively pursued.

If the Chelsea-Hackney line is built then it is intended that it will take over the Epping branch of the Central line. Current hopes are that this will be completed by 2025.

It would be possible to provide an interchange with London Overground at Shoreditch High Street station which is due to open in 2010 but current thinking is that the disadvantages to existing passengers outweigh the benefits.

References

1. First Central Business Park
2. Crossrail official site
3. PDF on the route options

External links

• 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.