The Northern line is a London Underground line which runs between North London and South London. It is printed in black on the Tube map. It carries more passengers per year than any other Underground linearound 340million in 2019making it the busiest tube line in London. The Northern line is unique on the network in having two routes through Central London, two northern branches and two southern branches. Despite its name, it does not serve the northernmost stations on the Underground, though it does serve the southernmost station at Morden, the terminus of one of the two southern branches.

The line's northern termini, all in the London Borough of Barnet, are at and ; is the terminus of a single-station branch line off the High Barnet branch. The two main northern branches run south to join at where two routes, one via in the West End and the other via in the City, continue and then join at in Southwark. At Kennington the line again divides into two branches, one to each of the southern termini – at , in the borough of Merton, and at in Wandsworth.

For most of its length the Northern line is a deep tube line. The portion between and opened in 1890 and is the oldest section of deep-level tube line on the network. Nearly 340 million passenger journeys were recorded in 2019 on the Northern line, making it the busiest on the Underground, although this is distorted due to having two branches within Central London, both of which are less busy than the core sections of other lines. Construction began in 1922 and this first tunnel opened in 1924. The second connection linking the CCE&HR's Embankment and C&SLR's Kennington stations opened in 1926. It provided a new intermediate station at Waterloo to connect to the main line station. The smaller diameter tunnels of the C&SLR were also enlarged to match the standard diameter of the CCE&HR and other deep tube lines. In conjunction with the works to integrate the two lines, two major extensions were undertaken: northwards to Edgware in Middlesex and southwards to Morden in Surrey.

The Edgware extension used plans dating back to 1901 for the Edgware and Hampstead Railway which the UERL's subsidiary, the London Electric Railway, had taken over in 1912. It extended the CCE&HR line from its terminus at Golders Green to Hendon Central in 1923 and to Edgware in 1924. The line crossed open countryside and ran mostly on viaduct from Golders Green to Brent and then on the surface, apart from a short tunnel north of Hendon Central. Five new stations were built to pavilion-style designs by Stanley Heaps, stimulating the rapid northward expansion of suburban developments in the following years.

The engineering of the Morden extension of the C&SLR from Clapham Common to Morden was more demanding, running in tunnel to Morden station which was then constructed in a cutting and the line continued a bit beyond to the depot. The extension was initially planned to continue to Sutton over part of the route of the unbuilt Wimbledon and Sutton Railway (in which the UERL held a stake) but agreements were made with Southern Railway (SR) to end the extension at Morden, the SR building a surface line from Wimbledon to Sutton in the 1930s via South Merton and St. Helier. The tube extension itself opened in 1926 with seven new stations all designed by Charles Holden in a modern style.

Owing to the complicated nature of the resulting line, it became known as the Morden–Edgware line, although a number of alternative portmanteau names were mooted in the fashion of the Baker Street and Waterloo Railway becoming the Bakerloo line, such as "Edgmor", "Mordenware", "Medgeway" and "Edgmorden" lines.

After the UERL and the Metropolitan Railway (MR) became unified under the London Passenger Transport Board (LPTB) in 1933, the MR's Great Northern & City Railway subsidiary, which ran mostly underground from Moorgate to Finsbury Park, transferred management to the Morden–Edgware line, branding itself as the Northern City line.

<span class="anchor" id="The Northern Heights plan"></span> Northern Heights plan

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thumb|Line map of the abandoned Northern Heights plan

thumb|Sign displaying the route of the Northern Heights extension

Following the formation of the LPTB, in June 1935 the organisation proposed the New Works Programme, an ambitious plan to expand the Underground network in response to London's growing suburban population and to relieve congestion on the existing steam-operated suburban lines. In the case of the Morden–Edgware, these were the London and North Eastern Railway (LNER) suburban lines north of Highgate, built in the 1860s and 1870s by the Edgware, Highgate and London Railway (EH&LR) and its successors, running from Finsbury Park to Edgware via Highgate, with branches to Alexandra Palace and High Barnet.

The Morden–Edgware line's project, known as the Northern Heights plan owing to the high ground in north London, involved fourth-rail electrification of the surface lines and the double-tracking of the single-line section between Finchley (Church End) and Edgware. The Northern Heights plan also called for the construction of three new linking sections of track: between the Northern City line and new surface level platforms at Finsbury Park; a deep-level tunnel from Archway to East Finchley; and a diversion of the Mill Hill branch to the LPTB's Edgware station. As a result of the project's name, the Morden–Edgware line was renamed as the Northern line on 28 August 1937.

Work began on the initial stages of the extensions in 1936, as did that on Bushey Heath following its authorisation in 1937, with completion projected by 1941. The tunnelling northwards from Archway was the first element to be completed and an initial service to the rebuilt East Finchley station commenced on 3 July 1939, though trains skipped the deep-level platforms at Highgate until its fitout was completed by 19 January 1941.

Further progress was disrupted by the start of the Second World War in September 1939; however enough development had been made to complete the electrification of the High Barnet branch, over which tube services started on 14 April 1940, and the single-track LNER line to Edgware being electrified as far as Mill Hill East, reopening as a tube service on 18 May 1941 to serve the nearby Inglis Barracks. The partially-complete depot at Aldenham was converted into an aircraft factory, constructing Handley Page Halifax bombers as part of the war effort. Other work on the extension that were eventually halted during the Second World War included the construction of a viaduct at Brockley Hill and a tunnel near Elstree South which started in June 1939, the laying of a second line as far as Mill Hill (The Hale) and the construction of its second platform.

Independent of the Northern Heights plan was an intention to introduce nine-car trains on the Northern line as a response to severe overcrowding. While several existing surface station platforms were lengthened to accommodate two additional cars, the deep-level platforms were not easily rebuilt, although Highgate's new platforms were built nine-car trains in mind, so selective door operation was introduced whereby two cars of the train had its doors locked in the tunnel. Nine-car operations began in November 1937 between Edgware and Kennington via Charing Cross, with ten new 1938 Stock trains being fitted with selective door operation. By the start of the War, nine-car trains were discontinued and never revived.

After the war, much of the area beyond Edgware was made part of the Metropolitan Green Belt that largely prevented the anticipated residential development, thus the potential demand for services from Bushey Heath vanished. Although efforts were made to complete Aldenham Depot as an Underground facility, from December 1947 it was modified for use as a heavy repair works of bus bodies, supposedly temporarily until Aldenham was required for railway purposes. Following the extension's cancellation, the depot was converted into an overhaul facility for buses, serving this purpose until 1986.

The introduction of electric services to High Barnet and Mill Hill East undermined passenger numbers on the remaining LNER-operated lines. Consequently, passenger services to Mill Hill (The Hale) and Edgware, having been suspended in September 1939 to allow works to be completed, never resumed Tickets were still being sold to and from Mill Hill (The Hale) until the late 1960s, with passengers being directed onto the 240 bus to connect with the Underground. Further proposals included building additional tunnels between Kennington and Tooting Broadway to relieve congestion, with alternative duplication suggested between Golders Green and Waterloo. In the 1980s, an extension of the Northern line to Peckham Rye and Streatham Hill was proposed as part of a review of potential extensions of Underground lines.

Between 1989 and 1992, Angel tube station was rebuilt with a new northbound tunnel alongside the existing station platforms which were widened to become the new southbound platform, replacing the old narrow platforms which by then had become a safety hazard with increased passenger ridership. A similar project was undertaken at Euston in the 1960s in conjunction with the construction of the Victoria line

By the early 1990s, the line had deteriorated due to years of under-investment and the use of old rolling stock, most of which dated back to the early 1960s. The line gained the nickname "Misery Line" due to its perceived unreliability. In 1995, a comprehensive refurbishment of the line began – including track replacement, power upgrades, station modernisation (such as Mornington Crescent) and the replacement of older rolling stock with new 1995 Stock thanks to a public–private partnership deal with Alstom.

The Northern line was originally scheduled to switch to automatic train operation in 2012, using the same SelTrac S40 system as used since 2009 on the Jubilee line and for a number of years on the Docklands Light Railway. Originally the work was to follow on from the Jubilee line so as to benefit from the experience of installing it there, but that project was not completed until spring 2011. Work on the Northern line was contracted to be completed before the 2012 Olympics. It was then undertaken in-house, and TfL predicted the upgrade would be complete by the end of 2014. The first section of the line (West Finchley to High Barnet) was transferred to the new signalling system on 26 February 2013 and the line became fully automated on 1 June 2014, with the Chalk Farm to Edgware via Golders Green section being the last part of the line to switch to ATO.

Since the mid-autumn of 2016, a 24-hour "Night Tube" service has run on Friday and Saturday nights from Edgware and High Barnet to Morden via the Charing Cross branch; service is suspended on the Bank branch during these times. Trains run every eight minutes between Morden and Camden Town and up to every 16 minutes on the Edgware and High Barnet branches. Labour disputes delayed the planned start date of September 2015.

In January 2018, Transport for London announced that it would double the period during which it runs peak evening services in the central London section to tackle overcrowding. There would now be 24 trains per hour on both central London branches and the northern branches, as well as 30 trains per hour on the Kennington to Morden section between 5pm and 7pm.

Battersea extension

Throughout the 2000s, no plans were considered for extending the Northern line, as the PPP contracts to upgrade the Underground did not include provision for line extensions. This prolonged period without an extension ultimately changed when the Northern line was extended to serve the redevelopment of Battersea Power Station in 2021. Partially funded by private developers, the £1.2bn project extended the Charing Cross branch of the line for from Kennington to Battersea Power Station, with an intermediate stop at Nine Elms. Approved by Wandsworth Council in 2010 and TfL in 2014, Provision has been made for a future extension to Clapham Junction.

Services

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Peak

As of September 2021, morning peak southbound services are:

  • 10 tph from Edgware to Battersea Power Station via Charing Cross
  • 10 tph from Edgware to Morden via Bank
  • 8 tph from High Barnet to Battersea Power Station via Charing Cross
  • 8 tph from High Barnet to Morden via Bank
  • 2 tph from Mill Hill East to Battersea Power Station via Charing Cross
  • 2 tph from Mill Hill East to Morden via Bank

This service pattern provides 16 tph between Finchley Central and High Barnet, 4 tph between Finchley Central and Mill Hill East, and 20 tph everywhere else on the line.

Night

Since 2016, the Northern line has operated Night Tube services on Friday and Saturday nights between the Edgware and High Barnet termini and Morden via the Charing Cross branch only. Trains run every 15 minutes on each of the northern branches, combining to give eight trains per hour between Camden Town and Morden. There is no Night Tube service on the Mill Hill East, Bank or Battersea branches.

Transfers of 1956 and 1959 Stock began in 1975, which coincided with the 1972 Mark II Stock being transferred onto the Bakerloo line prior to the Jubilee line's opening in 1979. With the introduction of the first batch of 1983 Stock on the Jubilee line, half of the 1972 Mark II Stock returned to the Northern line to enable the some 1959 Stocks to transfer to the Bakerloo line as a stopgap to replace the final remainder of the 1938 Stock in November 1985. However, resurgence in passenger numbers from the mid-1980s ironically resulted in five 1938 Stock trains to be renovated and returned to service on the Northern line from 1986. The introduction of the second batch of 1983 Stock prompted the transfer of all 1972 Mark II Stocks onto the Bakerloo line which handed the 1959 Stocks back to the Northern line for the final withdrawal of 1938 Stock trains in May 1988.

Following the introduction of the 1992 Stock on the Central line, some 1962 Stock trains transferred to the Northern line in 1994 to replace the non-standard 1956 Stock trains. While a new fleet of trains were looked upon by the Underground, budget constraints and the mid-life age of the 1972 Mark I Stock gave way to the idea of retaining and refurbishing the latter while running alongside the new trains. The 1972 Stock began to be refurbished in 1994 to a similar level to those of the Mark II Stock except for the immediate conversion to one-person operation which was expected to occur later. However, only three trains were completed before a Private finance initiative deal between London Underground and Alstom was made for the procurement of 106 new trains coming in the form of the 1995 Stock which eliminated any non-standard fleets. Their introduction began in 1998 and withdrawals of the existing stock took place from that year, with the final "Silver train" being a 1959 Stock train running in service on 27 January 2000.

Today, all Northern line trains consist of the 1995 Stock. In common with the other deep-level lines, the trains are the smaller of the two loading gauges used on the system. If the proposed split of the line takes place (initial estimates of 2018 having been abandoned to focus on completion of the Battersea and Nine Elms extension work), 19 new trains will be added to the existing fleet of 106 trains, though additional trains beyond the extra 19 trains may be required to provide a full service for the new Battersea extension.

Tunnels

Although two other London Underground lines operate fully underground, the Northern line is unusual in that it is a deep-level tube line that serves the outer suburbs of South London yet there is only one station above ground (Morden tube station) while the rest of this part of the line is deep below ground. The short section to Morden depot is also above ground. This is partly because its southern extension into the outer suburbs was not done by taking over an existing surface line as was generally the case with routes such as the Central, Jubilee and Piccadilly lines. Apart from the core central underground tunnels, part of the section between Hendon and Colindale is also underground. As bicycles are not allowed in tunnel sections (even if no station is in that section) as they would hinder evacuation, they are limited to High Barnet – East Finchley, the Mill Hill East branch, Edgware – Colindale and Hendon Central – Golders Green. There are also time-based restrictions for the sections where bicycles are allowed. Running trains between all combinations of branches and the two central sections, as at present, means only 24 trains an hour can run through each of the central sections at peak times, because merging trains have to wait for each other at the junctions at Camden Town and Kennington. Completely segregating the routes could allow 36 trains an hour on all parts of the line, increasing capacity by around 25%. The extension to Battersea would allow the Charing Cross branch to terminate at Battersea Power Station.

The proposed split of the Northern line would require Camden Town station to be expanded and upgraded, as the station is already severely overcrowded at weekend peak times, and a split would increase the number of passengers wishing to change trains at the station. New redevelopment plans were first announced in 2013 by TfL, which proposed avoiding the existing station entrance and the conservation area by building a second entrance and interchange tunnels to the north, mostly on the site of a subsequently vacated infant school. , TfL said they still "aspire" to split the line. A partial separation was proposed in which all trains from Morden would operate via Bank, while those starting at Kennington (or Battersea) would serve the Charing Cross branch. The High Barnet and Edgware branches would remain served by trains from both routes.

Incidents and accidents

In October 2003, a train derailed at Camden Town. Although no one was hurt, points, signals and carriages were damaged. Concern was raised about the safety of the Tube, given the derailment at Chancery Lane earlier in 2003. A joint report by the Underground and its maintenance contractor Tube Lines concluded that poor track geometry was the main cause, and therefore extra friction arising out of striations (scratches) on a newly installed set of points had allowed the leading wheel of the last carriage to climb the rail and derail. The track geometry at the derailment site is a very tight bend and tight tunnel bore, which precludes the normal solution for this sort of geometry of canting the track by raising the height of one rail relative to the other.

In August 2010, a defective rail grinding train caused disruption on the Charing Cross branch, after it travelled four miles in 13 minutes without a driver. The train was being towed to the depot after becoming faulty. At Archway station, the defective train became detached and ran driverless until coming to a stop at an incline near Warren Street station. This caused morning rush-hour services to be suspended on this branch. All passenger trains were diverted via the Bank branch, with several not stopping at stations until they were safely on the Bank branch.

  • In his debut novel Ghostwritten, David Mitchell characterises the Northern line as "the psycho of the family".
  • The Bloc Party song "Waiting For the 7.18" references the Northern line as "the loudest".
  • As part of a series of twelve books tied to the twelve lines of the London Underground, A Northern Line Minute focuses on the Northern line.
  • The New Vaudeville Band's 1967 song "Finchley Central" ("On Tour" in the US) mentions several stations on the line.
  • The Nick Drake song "Parasite" references the Northern Line.
  • The 1982 Robyn Hitchcock song "Fifty Two Stations" begins, "There's fifty-two stations on the Northern Line/None of them is yours, one of them is mine."
  • The 2021 Maisie Peters song "Elvis Song" begins, "Cold bench on a platform/Last train on the Northern Line."

Maps

  • High Barnet –
  • Totteridge & Whetstone –
  • Woodside Park –
  • West Finchley –
  • Mill Hill East –
  • Finchley Central –
  • East Finchley –
  • Highgate –
  • Archway –
  • Tufnell Park –
  • Kentish Town –
  • Edgware –
  • Burnt Oak –
  • Colindale –
  • Hendon Central –
  • Brent Cross –
  • Golders Green –
  • Hampstead –
  • Belsize Park –
  • Chalk Farm –
  • Camden Town –
  • Mornington Crescent –
  • Euston –
  • Warren Street –
  • Goodge Street –
  • Tottenham Court Road –
  • Leicester Square –
  • Charing Cross –
  • Embankment –
  • Waterloo –
  • King's Cross St Pancras –
  • Angel –
  • Old Street –
  • Moorgate –
  • Bank-Monument –
  • London Bridge –
  • Borough –
  • Elephant & Castle –
  • Kennington –
  • Oval –
  • Stockwell –
  • Clapham North –
  • Clapham Common –
  • Clapham South –
  • Balham –
  • Tooting Bec –
  • Tooting Broadway –
  • Colliers Wood –
  • South Wimbledon –
  • Morden –
  • Golders Green depot –
  • Morden depot –

See also

  • T. P. Figgis, architect of the City and South London Railway's original stations
  • Leslie Green, architect of the Charing Cross, Euston and Hampstead Railway's early stations
  • List of crossings of the River Thames
  • London deep-level shelters, most of which are under Northern line stations
  • Tunnels underneath the River Thames

References

Notes

Citations

Bibliography

  • Architectural history of London Underground during 1920-30s from the Royal Institute of British Architects
  • Old Street, Angel and Stockwell stations
  • South Clapham, Tooting Bec and South Wimbledon