View source for Northern line

{{short description|London Underground line}}
{{about|the London Underground line}}
{{Use dmy dates|date=July 2024}}
{{Infobox rail line
| name                            = Northern line
| logo                            = London flag boxes - Underground Northern line.svg
| logo_width                      = 250px
| logo_alt                        = 
| image                           = Northern line tube stock at Stockwell, July 2024.jpg
| image_width                     = 250px
| image_alt                       = 
| caption                         = 1995 Stock arrives at [[Stockwell tube station]] heading northbound to Edgware via Bank, July 2024
| type                            = [[Rapid transit]]
| system                          = [[London Underground]]
| start                           = Kennington, Battersea Power Station, Morden
| mapcolour                       = Black
| mapcolourlink                   = Tube map
| end                             = Edgware, High Barnet, Mill Hill East
| stations                        = 52
| ridership2                      = 339.7 million passenger journeys (2019)<ref>{{cite web |title=London Assembly Questions to the Mayor |url=https://www.london.gov.uk/who-we-are/what-london-assembly-does/questions-mayor/find-an-answer/tube-usage-1|publisher=London Assembly |year=2022 |access-date=29 February 2024}}</ref>
| open                            = {{start date and age|df=y|1890|12|18}} {{efn|as City and South London Railway. Charing Cross, Euston & Hampstead Railway opened its section in {{start date and age|df=y|1907|06|22}}. Lines merged in {{start date and age|df=y|1926|09|13}}. Renamed to Northern line in {{start date and age|df=y|1937|08|28}}}}
| lastextension                   = {{start date and age|df=y|2021|9|20}}
| character                       = Deep-tube
| depot                           = {{plainlist|
* {{cslist|Golders Green|Morden}}
* [[Stabling point|Stabling Sidings]]: {{cslist|Highgate|Edgware|High Barnet<ref name="linefact">{{cite web |title=Northern line facts |url= http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/keyfacts/13174.aspx |archive-url=https://web.archive.org/web/20120312094056/https://tfl.gov.uk/corporate/modesoftransport/londonunderground/keyfacts/13174.aspx |archive-date=12 March 2012 |publisher=Transport for London |access-date=12 March 2012}}</ref>}}
}}
| stock                           = [[London Underground 1995 Stock|1995 Stock]]
| gauge                           = {{track gauge|sg|allk=on}}
| electrification                 = {{630 V DC|conductor=fourth rail}}
| speed                           = {{convert|45|mph|abbr=on}}<ref>{{Cite web |date=18 September 2017 |title=City Metric |url=https://www.citymetric.com/transport/which-london-underground-line-fastest-3322|access-date=22 October 2023 |website=Centre for Cities|archive-url=https://web.archive.org/web/20171022142712/https://www.citymetric.com/transport/which-london-underground-line-fastest-3322 |archive-date=22 October 2017 }}</ref>
| signalling                      = [[Communications-based train control|CBTC]] (SelTrac)
| linelength_km                   = 58
| tracklength_km                  = 
| website                         = {{Official URL}}
| map_name                        = [[Transport for London]] rail&nbsp;lines
| map                             = {{London rail lines}}
| map_state                       = collapsed
}}

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 line{{snd}}around 340{{nbsp}}million in 2019{{snd}}making 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 tube station|Morden]], the terminus of one of the two southern branches. 

The line's northern termini, all in the [[London Borough of Barnet]], are at {{lus|Edgware}} and {{lus|High Barnet}}; {{lus|Mill Hill East}} is the terminus of a single-station branch line off the High Barnet branch. The two main northern branches run south to join at {{lus|Camden Town}} where two routes, one via {{lus|Charing Cross}} in the [[West End of London|West End]] and the other via {{lus|Bank}} in the [[City of London|City]], continue and then join at {{lus|Kennington}} in [[London Borough of Southwark|Southwark]]. At Kennington the line again divides into two branches, one to each of the southern termini – at {{lus|Morden}}, in the borough of [[London Borough of Merton|Merton]], and at {{lus|Battersea Power Station}} in [[London Borough of Wandsworth|Wandsworth]].

For most of its length the Northern line is a deep tube line.{{efn|A "tube" railway is an underground railway constructed in a cylindrical tunnel by the use of a [[tunnelling shield]], usually deep below ground level.}} The portion between {{lus|Stockwell}} and {{lus|Borough}} opened in 1890 and is the oldest section of deep-level tube line on the network. Nearly 340&nbsp;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.<ref name="cityam" /> Despite the line's name, it has 18 of the system's 31 stations south of the [[River Thames]]. There are 52 stations in total on the line, of which 38 have platforms below ground.

The line's structure of two northern branches (one with a further short branch), two central branches, and two southern branches reflects its complicated history. The core of the line, including the two central branches and the beginnings of the two northern branches, was constructed by two companies, the [[City and South London Railway]] and the [[Charing Cross, Euston and Hampstead Railway]], in the 1890s and 1900s. The companies came under the same ownership in 1913, and were physically connected and operationally merged in the 1920s, while at the same time extensions to Edgware and Morden were completed. In the 1930s and 1940s the Northern line took over and electrified the [[London and North Eastern Railway]] branches to Mill Hill East and High Barnet. This was the final extension of the line for eight decades, though between the 1930s and 1970s the [[Northern City Line]] was branded and operated as part of the Northern line despite being disconnected from the rest of the line. The most recent extension, [[Northern line extension to Battersea|a second southern branch from Kennington to Battersea]], opened on 20 September 2021. There are proposals to split the line into two lines.
{{TOC limit|4}}

==History==
{{more citations needed|section|date=June 2019}}

===Formation===
{{Broader|City and South London Railway|Charing Cross, Euston and Hampstead Railway|topic=the detailed histories of the original companies}}
[[File:Electric railway train.jpg|upright=1.6|thumb|City & South London Railway train, 1890]]
The core of the Northern line evolved from two railway companies: the City & South London Railway (C&SLR) and the Charing Cross, Euston & Hampstead Railway (CCE&HR).

The C&SLR was London's first electric hauled deep-level tube railway. It was built under the supervision of [[James Henry Greathead]], who had been responsible for the [[Tower Subway]].{{sfn|Badsey-Ellis|2005|p=35}} It was the first of the Underground's lines to be constructed by boring deep below the surface and the first to be operated by electric traction.{{sfn|Wolmar|2005|pp=4 & 135}} The railway opened in November 1890 from [[Stockwell tube station|Stockwell]] to a now-disused station at [[King William Street tube station|King William Street]].{{sfn|Horne|2009|p=10}} This was inconveniently placed and unable to cope with the company's traffic so in 1900 a new route to [[Moorgate station|Moorgate]] via [[Bank–Monument station|Bank]] was opened.{{sfn|Horne|2009|p=14}} By 1907, the C&SLR had been further extended at both ends to run from [[Clapham Common tube station|Clapham Common]] to [[Euston tube station|Euston]].{{sfn|Horne|2009|pp=16–18}}

[[File:Formation of the Northern Line small.png|frame|Formation of the Northern line up to the 1920s]]

The CCE&HR, commonly known as the "Hampstead Tube", was opened in 1907 and ran from Strand (nowadays [[Charing Cross tube station|Charing Cross]]) via Euston to [[Camden Town tube station|Camden Town]] with branches splitting to [[Golders Green tube station|Golders Green]] and Highgate (nowadays [[Archway tube station|Archway]]).{{sfn|Horne|2009|p=26}}{{sfn|Rose|2016}} It was extended south by one stop to Charing Cross (nowadays [[Embankment tube station|Embankment]]) in 1914 to form an interchange with the [[Bakerloo line|Bakerloo]] and [[District line]]s.{{sfn|Rose|2016}}{{sfn|Horne|2009|p=27}} In 1913, the [[Underground Electric Railways Company of London]] (UERL), owner of the CCE&HR, took over the C&SLR although they remained separate companies for some time.{{sfn|Wolmar|2005|p=205}}

===Integration===
During the early 1920s a series of works were carried out to connect the C&SLR and CCE&HR tunnels to enable an integrated service to be operated. The first of these new tunnels between the C&SLR's Euston and CCE&HR's Camden Town stations had originally been planned in 1912 but was delayed by the [[World War I|First World War]].<ref name="gazette_1">{{London Gazette |issue=28665 |date=22 November 1912 |page=8798}}</ref>{{sfn|Horne|2009|p=32}} Construction began in 1922 and this first tunnel opened in 1924.{{sfn|Rose|2016}}{{sfn|Horne|2009|p=32}} The second connection linking the CCE&HR's Embankment and C&SLR's [[Kennington tube station|Kennington]] stations opened in 1926.{{sfn|Rose|2016}}{{sfn|Horne|2009|p=32}} It provided a new intermediate station at [[Waterloo tube station|Waterloo]] to connect to [[London Waterloo station|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.{{sfn|Horne|2009|pp=32–33}} 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 [[Charing Cross, Euston and Hampstead Railway#Hampstead Heath controversy|Edgware and Hampstead Railway]]<ref name=gazette_2>{{London Gazette |issue=27380 |date=26 November 1901 |page=8200}}</ref> which the UERL's subsidiary, the [[London Electric Railway]], had taken over in 1912.{{sfn|Horne|2009|p=28}} It extended the CCE&HR line from its terminus at Golders Green to [[Hendon Central tube station|Hendon Central]] in 1923 and to [[Edgware tube station|Edgware]] in 1924.{{sfn|Rose|2016}}{{sfn|Horne|2009|p=29}} The line crossed open countryside and ran mostly on viaduct from Golders Green to [[Brent Cross tube station|Brent]] and then on the surface, apart from a short tunnel north of Hendon Central.{{sfn|Horne|2009|p=29}} Five new stations were built to pavilion-style designs by [[Stanley Heaps]], stimulating the rapid northward expansion of suburban developments in the following years.{{sfn|Day|Reed|2010|p=91}}

The engineering of the Morden extension of the C&SLR from Clapham Common to Morden was more demanding, running in tunnel to [[Morden tube station|Morden station]] which was then constructed in a cutting and the line continued a bit beyond to the depot. The extension was initially [[Sutton Underground Line Proposal|planned]] to continue to [[Sutton (Surrey) railway station|Sutton]]<ref name=gazette_3>{{London Gazette |issue=32770 |date=24 November 1922 |pages=8314–8315}}</ref> 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 (Great Britain)|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.{{efn|The stations that the C&SLR were to serve on the W&SR, would not have included all those subsequently built by the Southern Railway. [[Morden tube station (District Railway)|South Morden]] (not built), [[Sutton Common railway station|Sutton Common]], [[Cheam tube station|Cheam]] (not built) and Sutton, would have been served, but [[Morden South railway station|Morden South]], [[St Helier railway station|St Helier]] and [[West Sutton railway station|West Sutton]] were not part of the UERL's plan.}} 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.{{sfn|Wolmar|2005|p=225}}

After the UERL and the [[Metropolitan Railway]] (MR) became unified under the [[London Passenger Transport Board]] (LPTB) in 1933, the MR's [[Northern City Line|Great Northern & City Railway]] subsidiary, which ran mostly underground from Moorgate to [[Finsbury Park station|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===
<!-- This section and its anchor is linked from [[Closed London Underground stations]] and from [[Charing Cross, Euston and Hampstead Railway]] -->
{{redirect|Northern Heights|the neighbourhood in Sudbury, Ontario|Urban neighbourhoods of Sudbury#Donovan/Northern Heights|the condominium/mall in Yellowknife, Northwest Territories|Centre Square Mall}}
{{Broader|Edgware, Highgate and London Railway|topic=the detailed history}}
[[File:Northern Heights diagram.png|thumb|Line map of the abandoned Northern Heights plan]]
[[File:Northern Line Northern Heights Extension sign.jpg|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 locomotive|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 railway station|Edgware]] via Highgate, with branches to [[Alexandra Palace railway station (Muswell Hill branch)|Alexandra Palace]] and [[High Barnet tube station|High Barnet]].

The Morden–Edgware line's project, known as the Northern Heights plan owing to the high ground in north London,<ref>{{Cite web |url=https://trainstobeyond.com/northern-heights/ |title=The Northern Heights |website=Trains to Beyond |author=Chris Sutton |date=27 April 2021 }}</ref> involved [[Railway electrification in Great Britain#London Underground|fourth-rail electrification]] of the surface lines and the [[Double-track railway|double-tracking]] of the single-line section between [[Finchley Central tube station|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 tube station|East Finchley]]; and a diversion of the Mill Hill branch to the LPTB's Edgware station.<ref name="Northern Wastes" />

In addition, the Edgware branch would also be extended beyond the terminus to a site at [[Bushey Heath tube station|Bushey Heath]], the LPTB having retained planning rights of the unbuilt [[Watford and Edgware Railway]], which had long intended an extension of the EH&LR's Edgware branch towards [[Watford]]. [[Aldenham Works|A new depot at Aldenham]], just before the Bushey Heath terminus, would also be constructed to facilitate the housing of additional trains.<ref name="Beyond Edgware">{{Cite book |title=By Tube Beyond Edgware |author=Tony Beard |year=2002 |publisher=Capital Transport}}</ref> As a result of the project's name, the Morden–Edgware line was renamed as the Northern line on 28 August 1937.<ref>{{Cite web |url=https://www.ltmuseum.co.uk/collections/stories/transport/northern-line |website=London Transport Museum |title=The Northern line}}</ref><ref>Rails through the Clay; Croome & Jackson; London; 2nd ed; 1993; p228</ref><ref name="new name">{{cite journal |date=25 August 1937 |title=London Tubes' New Names – Northern and Central Lines |journal=The Times |issue=47772 |page=12 |url=http://infotrac.galegroup.com/itw/infomark/708/539/29061067w16/purl=rc1_TTDA_0_CS203370777&dyn=52!xrn_7_0_CS203370777&hst_1?sw_aep=kccl |access-date=18 May 2009}}{{Subscription required}}</ref>

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.<ref name="Northern Wastes">{{Cite book |title=Northern Wastes |author1=Jim Blake |author2=Jonathan James |year=1987 |publisher=Platform 10}}</ref> 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 [[World War II|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 tube station|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.<ref name="Beyond Edgware" /><ref>{{Cite web |url=https://content.tfl.gov.uk/halifax-plane-production-by-lptb-during-wwii.pdf |title=Halifax Plane Production by LPTB during WWII |website=Transport for London |date=November 2020}}</ref> Other work on the extension that were eventually halted during the Second World War included the construction of a viaduct at [[Brockley Hill tube station|Brockley Hill]] and a tunnel near [[Elstree South tube station|Elstree South]] which started in June 1939, the laying of a second line as far as [[Mill Hill (The Hale) railway station|Mill Hill (The Hale)]] and the construction of its second platform.<ref name="Mill Hill (The Hale)">{{Cite web |url=http://www.disused-stations.org.uk/m/mill_hill_hale/index.shtml |website=Disused Stations |title=Mill Hill (The Hale) |author=Nick Catford}}</ref>

Independent of the Northern Heights plan was an intention to introduce nine-car trains on the Northern line as a response to severe overcrowding.<ref>{{Cite book |title=London's Underground |author=John Glover |year=2003 |publisher=Ian Allan Publishing |page=68}}</ref> 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,<ref>{{Cite web |url=https://www.mylondon.news/lifestyle/travel/london-underground-bizarre-reason-northern-26565995 |title=The bizarre reason Northern line Tube trains leave huge gaps at some stations |website=MyLondon |author=Callum Cuddeford |date=27 March 2023}}</ref> 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 [[London Underground 1938 Stock|1938 Stock]] trains being fitted with selective door operation.{{sfn|Horne|2009|p=49}} 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.<ref name="Beyond Edgware" /> A compromise was offered to make Brockley Hill the line's terminus and retain a link to Aldenham Depot,<ref name="Northern Wastes" /> but the Bushey Heath extension was cancelled in 1950.<ref>{{Cite book |title=The London Transport Golden Jubilee Book |author1=Oliver Green |author2=John Reed |year=1983 |publisher=The Daily Telegraph}}</ref> 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 manufacturing#Bodywork|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.<ref>{{Cite web |url=https://content.tfl.gov.uk/research-guide-no-33-aldenham-bus-works.pdf |title=Research Guide No 33: Aldenham Bus Works |date=27 April 2016 |website=Transport for London}}</ref>

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<ref name="Mill Hill (The Hale)" /> and the Alexandra Palace branch line via the surface platforms at Highgate ceased to passenger traffic on 3 July 1954, with the last of the Northern Heights plans also being dropped that year.<ref name="Northern Wastes" /> Available funds were directed towards completing the eastern extension of the [[Central line (London Underground)|Central line]] instead. Freight-hauled mainline trains continued to run alongside Northern line services until 1964.<ref>{{Cite web |url=http://disused-stations.org.uk/e/edgware/index.shtml |title=Edgware (GNR) |website=Disused Stations |author=Nick Catford}}</ref> Tickets were still being sold to and from Mill Hill (The Hale) until the late 1960s, with passengers being directed onto [[London Buses route 240|the 240 bus]] to connect with the Underground.<ref name="Mill Hill (The Hale)" /> 

The connection between [[Drayton Park railway station|Drayton Park]] and the surface platforms at Finsbury Park, which gave access onto the Finsbury Park–Highgate line, was retained for rolling stock transfers between the Northern City and Northern line until 1970, the incomplete electrification on this section necessitating stock being hauled by [[London Underground battery–electric locomotives|battery-electric locomotives]].<ref name="Northern Wastes" /> Passenger services commenced on the Finsbury Park link in 1976, when the Northern City line transferred to [[British Rail]] ownership.

=== Recent developments ===
[[File:Northern line cab.JPG|thumb|Close-up of a [[High Barnet tube station|High Barnet]]-bound Northern line [[London Underground 1995 Stock|1995 stock]] cab|alt=]]
In a separate proposal to the New Works Programme, the LPTB looked into extending the Northern line south of Morden to [[North Cheam]] as late as 1944 alongside a relief line from Kennington to Epsom via Morden.<ref>{{Cite book |title=London's Underground Suburbs |author1=Dennis Edwards |author2=Ron Pigram |year=1988 |publisher=Bloomsbury}}</ref> Further proposals included building additional tunnels between Kennington and [[Tooting Broadway tube station|Tooting Broadway]] to relieve congestion, with alternative duplication suggested between Golders Green and Waterloo.<ref>{{Citation |url=https://archive.org/details/railways00609132/page/n23/mode/2up |title=Report to the Minister of War Transport |date=21 January 1946 |author=Railway (London Plan) Committee |pages=17–18}}</ref> In the 1980s, an extension of the Northern line to [[Peckham Rye railway station|Peckham Rye]] and [[Streatham Hill railway station|Streatham Hill]] was proposed as part of a review of potential extensions of Underground lines.<ref>{{cite web|date=May 1988 |first1=D R |last1=Mead |title=London Underground limited - Strategic Review - 1988 – New Lines and Extensions – Northern Line - Southern Extension To Peckham Rye Or Streatham |url=https://www.whatdotheyknow.com/request/244458/response/618034/attach/5/LUL%20Strategic%20Review%201988%20New%20lines%20and%20extensions%20Northern%20Line.pdf?cookie_passthrough=1|url-status=live|website=What Do They Know |publisher=London Underground|access-date=27 September 2021|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909142639/https://www.whatdotheyknow.com/request/244458/response/618034/attach/5/LUL%20Strategic%20Review%201988%20New%20lines%20and%20extensions%20Northern%20Line.pdf?cookie_passthrough=1}}</ref>

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.<ref name="Clive">{{Cite web |url=https://www.davros.org/rail/culg/northern.html |website=Clive's UndergrounD Line Guides |title=Northern Line}}</ref> A similar project was undertaken at Euston in the 1960s in conjunction with the construction of the [[Victoria line]]<ref name="Clive" /> and at Bank in the early 2020s in order to increase station capacity and improve accessibility.<ref>{{Cite magazine |url=https://www.newcivilengineer.com/latest/bank-station-upgrade-northern-line-reopens-after-blockade-success-16-05-2022/ |title=Bank station upgrade: Northern line reopens after blockade success |magazine=New Civil Engineer |author=Catherine Moore |date=16 May 2022}}</ref><ref>{{Cite web |url=https://tfl.gov.uk/info-for/media/press-releases/2022/october/next-phase-of-vital-upgrade-of-bank-station-completes-with-the-opening-of-a-new-interchange-route-between-the-northern-line-and-dlr |website=Transport for London |title=Next phase of vital upgrade of Bank station completes, with the opening of a new interchange route between the Northern line and DLR |date=13 October 2022}}</ref>

By the early 1990s, the line had deteriorated due to years of under-investment and the use of old [[London Underground rolling stock|rolling stock]], most of which dated back to the early 1960s.<ref>{{cite web |title=Northern Line (Hansard, 17 March 1994) |url=https://api.parliament.uk/historic-hansard/commons/1994/mar/17/northern-line |website=api.parliament.uk |access-date=27 May 2020 |archive-date=11 May 2021 |archive-url=https://web.archive.org/web/20210511074812/https://api.parliament.uk/historic-hansard/commons/1994/mar/17/northern-line |url-status=live}}</ref> The line gained the nickname "Misery Line" due to its perceived unreliability.<ref>{{cite web |archive-url=https://ghostarchive.org/varchive/youtube/20211211/i2O-w4vhaf4 |archive-date=11 December 2021 |last=Pearce |first=Mike |date=22 June 1989 |title=Northern Line driverless trains |url=https://www.youtube.com/watch?v=i2O-w4vhaf4 |via=YouTube |publisher=[[Thames Television]], [[Thames News]]}}{{cbignore}}</ref><ref name="misery1">{{cite news |title=Call for action on Northern Line |url=https://news.bbc.co.uk/2/hi/uk_news/england/london/4334700.stm |publisher=[[BBC News]] |date=12 October 2005 |access-date=10 June 2008 |archive-date=1 September 2007 |archive-url=https://web.archive.org/web/20070901010932/http://news.bbc.co.uk/1/hi/england/london/4334700.stm |url-status=live}}</ref> In 1995, a comprehensive refurbishment of the line began – including track replacement, power upgrades, station modernisation (such as [[Mornington Crescent tube station|Mornington Crescent]]) and the replacement of older rolling stock with new [[London Underground 1995 Stock|1995 Stock]] thanks to a [[public–private partnership]] deal with [[Alstom]].<ref>{{cite web|title=Tubular hell |url=http://www.independent.co.uk/news/tubular-hell-1281922.html|date=6 January 1997 |website=The Independent|location=London |access-date=27 May 2020|archive-date=15 May 2021 |archive-url=https://web.archive.org/web/20210515191000/https://www.independent.co.uk/news/tubular-hell-1281922.html|url-status=live}}</ref><ref>{{cite web |date=2000 |title=Northern line modernisation |url=http://www.londontransport.co.uk/underground/n_mod.htm |archive-url=https://web.archive.org/web/20000616133201/http://www.londontransport.co.uk/underground/n_mod.htm |archive-date=16 June 2000 |access-date=14 March 2021 |website=London Transport}}</ref>

The Northern line was originally scheduled to switch to [[automatic train operation]] in 2012, using the same [[SelTrac]] S40 system<ref name=thereg-20160809>{{cite news |last=Corfield |first=Gareth |title=London's 'automatic' Tube trains suffered 750 computer failures last year |url=https://www.theregister.co.uk/2016/08/09/london_underground_trains_stopped_750_times_automatic_train_operation_failure/ |url-status=live |newspaper=The Register |date=9 August 2016 |access-date=9 August 2016 |archive-url=https://web.archive.org/web/20160809093739/http://www.theregister.co.uk/2016/08/09/london_underground_trains_stopped_750_times_automatic_train_operation_failure/ |archive-date=9 August 2016}}</ref> as used since 2009 on the [[Jubilee line]] and for a number of years on the [[Docklands Light Railway]].<ref name="Tube Lines">{{cite press release |title=Network Tests for New Signalling Systems |url=http://www.tubelines.com/news/releases/200602/20050824.aspx |publisher=[[Tube Lines]] |date=24 August 2005 |archive-url=https://web.archive.org/web/20080105201220/http://www.tubelines.com/news/releases/200602/20050824.aspx |archive-date=5 January 2008}}</ref> 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 Summer Olympics|2012 Olympics]]. It was then undertaken in-house, and TfL predicted the upgrade would be complete by the end of 2014.<ref>{{cite web |url=http://www.tfl.gov.uk/assets/downloads/corporate/Part-1-Item06-Operational-Financial-Peformance-and-Investment-Programme-Reports-Q3-2012-13.pdf |publisher=Transport for London |date=6 February 2013 |title=Operational and Financial Performance Report and Investment Programme Report – Third Quarter, 2012/13 |access-date=1 March 2013 |archive-date=30 April 2013 |archive-url=https://web.archive.org/web/20130430154333/http://www.tfl.gov.uk/assets/downloads/corporate/Part-1-Item06-Operational-Financial-Peformance-and-Investment-Programme-Reports-Q3-2012-13.pdf |url-status=live}}</ref> The first section of the line (West Finchley to High Barnet) was transferred to the new signalling system on 26 February 2013<ref>{{cite press release |url=http://www.tfl.gov.uk/corporate/media/newscentre/archive/27303.aspx |publisher=Transport for London |date=26 February 2013 |title=Northern line upgrade one step closer}}</ref> 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.<ref>{{cite web|url=https://www.london.gov.uk/moderngov/documents/s40260/Transport%20Commitments%20Appendix%201.pdf |archive-url=https://web.archive.org/web/20210511105907/https://www.london.gov.uk/moderngov/documents/s40260/Transport%20Commitments%20Appendix%201.pdf |archive-date=2021-05-11 |url-status=live|title=Mayor of London – Transport Commitments}}</ref><ref>{{cite web|url=https://www.railengineer.co.uk/2015/05/08/lu-northern-line-goes-cbtc/|title=LU Northern line goes CBTC|last=Kessell|first=Clive|access-date=5 October 2019}}{{dead link|date=April 2023 |bot=InternetArchiveBot |fix-attempted=yes}}</ref>

Since the mid-autumn of 2016,<ref name=":3">{{cite web |url=https://tfl.gov.uk/campaign/tube-improvements/what-we-are-doing/night-tube |title=The Night Tube |publisher=Transport for London |access-date=28 September 2016 |archive-date=21 August 2020 |archive-url=https://web.archive.org/web/20200821161701/https://tfl.gov.uk/campaign/tube-improvements/what-we-are-doing/night-tube |url-status=live}}</ref> 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.<ref>{{cite web |url=https://tfl.gov.uk/campaign/tube-improvements/the-future-of-the-tube/night-tube |title=The Night Tube |date=n.d. |publisher=Transport for London |access-date=24 October 2015 |archive-date=11 July 2015 |archive-url=https://web.archive.org/web/20150711150816/https://tfl.gov.uk/campaign/tube-improvements/the-future-of-the-tube/night-tube |url-status=live}}</ref> 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.<ref>{{cite news |url=https://www.theguardian.com/uk-news/2015/aug/27/london-night-tube-plan-suspended |title=London night tube plan suspended |first=Gwyn |last=Topham |work=The Guardian |location=London |date=27 August 2015 |access-date=15 December 2016 |archive-date=1 January 2017 |archive-url=https://web.archive.org/web/20170101093815/https://www.theguardian.com/uk-news/2015/aug/27/london-night-tube-plan-suspended |url-status=live}}</ref>

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 5{{nbsp}}pm and 7{{nbsp}}pm.<ref name="cityam">{{cite news |url=http://www.cityam.com/279628/northern-line-passengers-get-quicker-and-more-frequent |title=Northern Line passengers to get quicker and more frequent journeys as TfL boosts services to tackle crowding on busiest Tube line |newspaper=[[City A.M.]] |location=London |date=29 January 2018 |access-date=29 January 2018 |first=Rebecca |last=Smith |url-status=dead |archive-url=https://web.archive.org/web/20180130064220/http://www.cityam.com/279628/northern-line-passengers-get-quicker-and-more-frequent |archive-date=30 January 2018}}</ref>

=== Battersea extension ===
{{main|Northern line extension to Battersea}}
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.<ref>{{cite web |title=Details of Tube modernisation plans unveiled |url=http://www.tubelines.com/news/releases/200602/20030108.aspx |website=Tube Lines |date=8 January 2003 |access-date=8 March 2021 |archive-url=https://web.archive.org/web/20060519094016/http://www.tubelines.com/news/releases/200602/20030108.aspx |archive-date=19 May 2006}}</ref><ref>{{cite web |last1=Shawcross |first1=Valerie |author1-link=Val Shawcross |last2=Livingstone |first2=Ken |author2-link=Ken Livingstone |title=Transport Plan – Southward Extensions |url=https://www.london.gov.uk/questions/2005/0820 |url-status=live |date=7 March 2005 |access-date=29 March 2021 |website=Mayor's Question Time |archive-url=https://web.archive.org/web/20210909142647/https://www.london.gov.uk/questions/2005/0820 |archive-date=9 September 2021}}</ref> 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 {{convert|3.2|km|mi|abbr=in}} from [[Kennington tube station|Kennington]] to [[Battersea Power Station tube station|Battersea Power Station]],<ref name=":0">{{cite news|last=Collier|first=Hatty|date=8 November 2017|title=Tunnelling work to extend Tube's Northern Line to Battersea completed|work=Evening Standard|location=London|url=https://www.standard.co.uk/news/transport/northern-line-extension-tunnelling-work-on-12bn-extension-to-battersea-completed-ahead-of-2020-a3685746.html|access-date=22 January 2018|archive-date=9 November 2020|archive-url=https://web.archive.org/web/20201109041335/https://www.standard.co.uk/news/transport/northern-line-extension-tunnelling-work-on-12bn-extension-to-battersea-completed-ahead-of-2020-a3685746.html|url-status=live}}</ref> with an intermediate stop at [[Nine Elms tube station|Nine Elms.]]<ref name=":1">{{cite press release|url=https://tfl.gov.uk/info-for/media/press-releases/2014/november/northern-line-extension-to-battersea-gets-go-ahead|date=12 November 2014|title=Northern line extension to Battersea gets go-ahead|publisher=Transport for London|access-date=22 January 2018|archive-date=26 May 2021|archive-url=https://web.archive.org/web/20210526082500/https://tfl.gov.uk/info-for/media/press-releases/2014/november/northern-line-extension-to-battersea-gets-go-ahead|url-status=live}}</ref><ref name=":2">{{cite web|title=Northern line extension |url=https://tfl.gov.uk/travel-information/improvements-and-projects/northern-line-extension|access-date=22 January 2018|publisher=Transport for London|archive-date=29 July 2019|archive-url=https://web.archive.org/web/20190729235927/https://tfl.gov.uk/travel-information/improvements-and-projects/northern-line-extension |url-status=live}}</ref> Approved by Wandsworth Council in 2010<ref>{{cite press release|title=Battersea Power Station scheme approved |url=http://www.wandsworth.gov.uk/news/article/10136/battersea_power_station_scheme_approved|publisher=[[London Borough of Wandsworth]]|date=11 November 2010|access-date=12 November 2010|archive-url=https://web.archive.org/web/20131014095827/http://www.wandsworth.gov.uk/news/article/10136/battersea_power_station_scheme_approved|archive-date=14 October 2013}}</ref> and TfL in 2014,<ref name=":1" /> construction began in 2015. Tunnelling for the project was completed in 2017,<ref name=":0" /> and the extension opened on 20 September 2021.<ref>{{cite web |last1=Prynn |first1=Jonathan|last2=Sleigh|first2=Sophia|date=21 December 2018|title=TfL under fire as Battersea Tube extension is delayed |url=https://www.standard.co.uk/news/transport/tfl-under-fire-as-battersea-tube-extension-is-delayed-by-miscalculations-a4023386.html|url-status=live|archive-url=https://web.archive.org/web/20201023202028/https://www.standard.co.uk/news/transport/tfl-under-fire-as-battersea-tube-extension-is-delayed-by-miscalculations-a4023386.html|archive-date=23 October 2020|access-date=3 February 2021|website=Evening Standard|location=London}}</ref><ref name="BBC-Battersea">{{cite news|date=20 September 2021|title=Northern line extension: Two new Tube stations open|publisher=BBC News|url=https://www.bbc.com/news/uk-england-london-58621491|access-date=20 September 2021|archive-date=20 September 2021|archive-url=https://web.archive.org/web/20210920073208/https://www.bbc.com/news/uk-england-london-58621491|url-status=live}}</ref> Provision has been made for a future extension to [[Clapham Junction railway station|Clapham Junction]].<ref>{{cite news|last=Henderson|first=Jamie|date=23 June 2013 |title=Clapham Junction next for Northern Line says London Assembly member|newspaper=Wandsworth Guardian|url=http://www.wandsworthguardian.co.uk/news/10501385.Clapham_Junction_next_for_Northern_Line_says_London_Assembly_member/|access-date=12 January 2014|archive-date=24 December 2013|archive-url=https://web.archive.org/web/20131224115148/http://www.wandsworthguardian.co.uk/news/10501385.Clapham_Junction_next_for_Northern_Line_says_London_Assembly_member/|url-status=live}}</ref>

==Services==
<!-- {{Citation needed|reason=unclear|date=September 2021}} -->

=== Peak ===
As of September 2021, morning peak southbound services are:<ref name="londonreconnections.com" />

*4 {{Abbr|tph|trains per hour}} from Edgware to Battersea Power Station via Charing Cross
*2 tph from Edgware to Morden via Charing Cross
*12 tph from Edgware to Morden via Bank
*10 tph from High Barnet to Battersea Power Station via Charing Cross
*2 tph from High Barnet to Morden 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 20 tph between Finchley Central and High Barnet, 4 tph between Finchley Central and Mill Hill East, 16 tph between Kennington and Battersea Power Station and 22 tph everywhere else on the line except between Kennington and Morden, between Camden Town and Finchley Central and on the Edgware branch where there are 24 tph.

=== Off-peak ===
As of November 2022, off-peak services are the similar to peak services, minus the four hourly trains that run from Morden to the northern branches via Charing Cross:<ref name="londonreconnections.com">{{cite web|last1=Purley |first1=Pedantic of |url=http://www.londonreconnections.com/2015/northern-line-timetable-for-the-future/|title=Twin Peaks: Timetable Changes on the Northern Line|work=London Reconnections|date=14 January 2015|access-date=25 October 2015|archive-date=12 May 2015|archive-url=https://web.archive.org/web/20150512144642/http://www.londonreconnections.com/2015/northern-line-timetable-for-the-future/|url-status=live}}</ref>

*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.<ref name=":3" />

*4 tph from High Barnet to Morden via Charing Cross
*4 tph from Edgware to Morden via Charing Cross

==Map==
[[File:Northern Line with Battersea.svg|thumb|upright=1.6|centre|Geographical path of the Northern line]]

==Stations==
{{Northern line map}}
[[File:Step-free access notification (Northern line).png|thumb|left|Notice explaining about step-free access. This can be found inside every Northern line train.]]
{{clear|left}}

===Open stations===
====High Barnet branch====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Branch !! Additional information
|-
| [[High Barnet tube station|High Barnet]] {{access icon}} || [[File:High Barnet stn entrance.JPG|100px]] || rowspan="3" | 1 April 1872 || rowspan="4" | High Barnet branch || Terminus. Northern line introduced 14 April 1940{{ref|map 1|map 1}}
|-
| [[Totteridge and Whetstone tube station|Totteridge & Whetstone]] || [[File:Totteridge & Whetstone stn building.JPG|100px]] || Northern line introduced 14 April 1940 {{ref|map 2|map 2}}
|-
| [[Woodside Park tube station|Woodside Park]] {{access icon}} || [[File:Woodside Park stn building.JPG|100px]] || Northern line introduced 14 April 1940{{ref|map 3|map 3}}
|-
| [[West Finchley tube station|West Finchley]] {{access icon}} || [[File:West Finchley stn entrance.JPG|100px]] || 1 March 1933 || Northern line introduced 14 April 1940{{ref|map 4|map 4}}
|-
| [[Mill Hill East tube station|Mill Hill East]] {{access icon}}|| [[File:Mill Hill East stn building.JPG|100px]] || rowspan="3" | 22 August 1867 || Mill Hill branch || Closed 11 September 1939, reopened 18 May 1941{{ref|map 5|map 5}}
|-
| [[Finchley Central tube station|Finchley Central]] {{access icon}} || [[File:Finchley Central station.jpg|100px]] || High Barnet & Mill Hill branches || First Northern line train was 14 April 1940{{ref|map 6|map 6}}
|-
| [[East Finchley tube station|East Finchley]] || [[File:East Finchley stn building.JPG|100px]] || rowspan="5" | High Barnet branch || First Northern line train was 3 July 1939{{ref|map 7|map 7}}
|-
| [[Highgate tube station|Highgate]] || [[File:Highgate station entrance Priory.JPG|100px]] || 19 January 1941 || Disused surface station opened 22 August 1867{{ref|map 8|map 8}}
|-
| [[Archway tube station|Archway]] || [[File:Archway station side entrance.JPG|100px]] || rowspan="3" | 22 June 1907 || Originally named Highgate{{ref|map 9|map 9}}
|-
| [[Tufnell Park tube station|Tufnell Park]] || [[File:Tufnell Park stn building.JPG|100px]] ||{{ref|map 10|map 10}}
|-
| [[Kentish Town station|Kentish Town]] {{rail-interchange|london|thameslink}} {{rail-interchange|gb|rail}}|| [[File:Kentish Town stn building.JPG|100px]] || Mainline station opened 13 July 1868. Connects with [[National Rail]] services.{{ref|map 11|map 11}}
|}

====Edgware branch====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Additional information
|-
| [[Edgware tube station|Edgware]] {{access icon}} || [[File:Edgware station building.JPG|100px]] || 18 August 1924 || Terminus{{ref|map 12|map 12}}
|-
| [[Burnt Oak tube station|Burnt Oak]] || [[File:Burnt Oak stn building.JPG|100px]] || 27 October 1924 || Opened with its current name, then renamed as "Burnt Oak (Watling)" approximately four years after its opening; was reverted to its original name in 1950.{{ref|map 13|map 13}}
|-
| [[Colindale tube station|Colindale]] || [[File:Colindale station entrance.JPG|100px]] || 18 August 1924 || Used as a terminus for some trains travelling north.{{ref|map 14|map 14}}
|-
| [[Hendon Central tube station|Hendon Central]] {{access icon}} || [[File:Hendon Central stn entrance.JPG|100px]] || rowspan="2" | 19 November 1923 || {{ref|map 15|map 15}}
|-
| [[Brent Cross tube station|Brent Cross]] || [[File:Brent Cross stn building.JPG|100px]] || Opened as "Brent"; renamed 20 July 1976.{{ref|map 16|map 16}}
|-
| [[Golders Green tube station|Golders Green]] {{access icon}} || [[File:Golders Green stn building.JPG|100px]] || rowspan="4" | 22 June 1907 || Originally a terminus; remains a terminus for some trains.{{ref|map 17|map 17}}
|-
| [[Hampstead tube station|Hampstead]] || [[File:Hampstead station building.JPG|100px]] || Originally proposed to be named "Heath Street"; this name can still be seen on wall tilings on station platform walls.{{ref|map 18|map 18}}
|-
| [[Belsize Park tube station|Belsize Park]] || [[File:Belsize Park stn building.JPG|100px]] || One of eight London Underground stations that have deep-level air-raid shelters underneath them. The shelter was constructed in the Second World War to provide safe accommodation for service personnel.{{ref|map 19|map 19}}
|-
| [[Chalk Farm tube station|Chalk Farm]] || [[File:Chalk Farm stn entrance.JPG|100px]] || {{ref|map 20|map 20}}
|}

====Camden Town====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Branch !! Additional information
|-
| [[Camden Town tube station|Camden Town]] || [[File:Camden Town stn building2.JPG|100px]] || 22 June 1907 || Edgware, High Barnet, Charing Cross and Bank branches{{efn|Charing Cross and Bank branches start immediately south of the station}} || The junctions connecting the two northern branches of the Northern line to the two central branches are just south of Camden Town station. The station has a pair of platforms on each of the two northern branches, and southbound trains can depart toward either Charing Cross or Bank from either of the two southbound platforms without crossing over.{{ref|map 21|map 21}} 
|}

====Charing Cross branch====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Additional information
|-
| [[Mornington Crescent tube station|Mornington Crescent]] || [[File:Mornington Crescent stn building.JPG|100px]] || rowspan="7" | 22 June 1907 || Was planned to be named "Seymour Street", but this was changed. It was closed on 23 October 1992 to replace the lifts and was reopened on 27 April 1998.{{ref|map 22|map 22}} 
|-
| [[Euston tube station|Euston (Charing Cross branch)]] {{rail-interchange|london|overground}} {{rail-interchange|gb|rail}} || [[File:Euston station facade.jpg|100px]] || Connects with southbound Northern line service via Bank from platform 6, [[Victoria line]], [[Lioness line]] and [[National Rail]] services.{{ref|map 23|map 23}}
|-
| [[Warren Street tube station|Warren Street]] || [[File:Warren Street stn entrance.JPG|100px]] || Connects with Victoria line.{{ref|map 24|map 24}}
|-
| [[Goodge Street tube station|Goodge Street]] || [[File:Goodge Street stn entrance.JPG|100px]] || Opened as "Tottenham Court Road"; renamed 3 September 1908.{{ref|map 25|map 25}}
|-
| [[Tottenham Court Road station|Tottenham Court Road]] {{access icon}} {{rail-interchange|london|elizabeth}} || [[File:Tottenham Court Road stn main entrance under refurb Oct 09.JPG|100px]] || Connects with [[Central line (London Underground)|Central line]] and the [[Elizabeth line]].
|-
| [[Leicester Square tube station|Leicester Square]] || [[File:Leicester Square stn northwest entrance.JPG|100px]] || [[Piccadilly line]] opened 15 December 1906. Connects with Piccadilly line.{{ref|map 27|map 27}}
|-
| [[Charing Cross tube station|Charing Cross]] {{rail-interchange|gb|rail}} || [[File:Charing Cross tube station 1.jpg|100px]] || [[Bakerloo line]] opened as Trafalgar Square 10 March 1906. Stations combined 1 May 1979. Connects with Bakerloo line and National Rail services.{{ref|map 28|map 28}}
|-
| [[Embankment tube station|Embankment]] ({{rail-interchange|london|river}} <small>[[Embankment Pier]]</small>) || [[File:Embankment station.jpg|100px]] || 6 April 1914 || District Railway opened 30 May 1870. Northern line extension from Charing Cross opened 6 April 1914. Extension from Kennington opened 13 September 1926. Connects with Bakerloo, [[Circle line (London Underground)|Circle]] and [[District line|District]] lines.{{ref|map 29|map 29}}
|-
| [[Waterloo tube station|Waterloo]] {{rail-interchange|gb|rail}} ({{rail-interchange|london|river}} <small>[[Waterloo Millennium Pier|Waterloo Pier]], [[Festival Pier]]</small>) || [[File:Waterloo tube stn entrance.JPG|100px]] || 13 September 1926 || Waterloo and City line opened 8 August 1898. Extension from Kennington opened 13 September 1926. Connects with Bakerloo, [[Jubilee line|Jubilee]] and [[Waterloo & City line|Waterloo & City]] lines, and National Rail services.{{ref|map 30|map 30}}
|}

====Bank branch====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Additional information
|-
| [[Euston tube station|Euston (Bank branch)]] {{rail-interchange|london|overground}} {{rail-interchange|gb|rail}} || [[File:Euston station facade.jpg|100px]] || rowspan="2" | 12 May 1907 || Connects with southbound Northern line service via Charing Cross from platform 2, [[Victoria line]], [[Lioness line]] and [[National Rail]] services.{{ref|map 23|map 23}}
|-
| [[King's Cross St Pancras tube station|King's Cross St Pancras]] {{access icon}} {{rail-interchange|london|thameslink}} {{rail-interchange|gb|rail}} {{rail-interchange|eurostar|}} ({{rail-interchange|air}} <small>Trains [[Gatwick Airport|Gatwick]] and [[London Luton Airport|Luton]]</small>) || [[File:King's Cross St Pancras tube stn Euston Rd NE entrance.JPG|100px]] || Metropolitan Railway station opened 10 January 1863. Connects with [[Circle line (London Underground)|Circle]], [[Hammersmith & City line|Hammersmith & City]], [[Metropolitan line|Metropolitan]], [[Piccadilly line|Piccadilly]] and Victoria lines, National Rail services and [[Eurostar]].{{ref|map 31|map 31}}
|-
| [[Angel tube station|Angel]] || [[File:Angel station entrance.JPG|100px]] || rowspan="2" | 17 November 1901 || Have the longest escalators on the entire Underground network.{{ref|map 32|map 32}}
|-
| [[Old Street station|Old Street]] {{rail-interchange|gb|rail}} || [[File:Old Street stn northwest entrance.JPG|100px]] || Northern line platforms opened February 1904. Connects with National Rail services.{{ref|map 33|map 33}}
|-
| [[Moorgate station|Moorgate]] {{rail-interchange|gb|rail}} {{rail-interchange|london|crossrail}} || [[File:Moorgate entrance Mgate.JPG|100px]] || rowspan="3" | 25 February 1900 || Metropolitan Railway station opened 23 December 1865. Connects with Circle, Hammersmith & City and Metropolitan lines, and National Rail services.{{ref|map 34|map 34}} Has an interchange with the Elizabeth line via [[Liverpool Street station]].
|-
| [[Bank and Monument stations|Bank]] {{access icon}} {{rail-interchange|london|dlr}} || [[File:Bank station entrance look to Bank.JPG|100px]] || Linked with Monument by escalator on 18 September 1933. Connects with [[Central line (London Underground)|Central]], Circle, [[District line|District]] and [[Waterloo & City line|Waterloo & City]] lines, and the [[Docklands Light Railway]] (DLR).{{ref|map 35|map 35}}
|-
| [[London Bridge station|London Bridge]] {{access icon}} {{rail-interchange|london|thameslink}} {{rail-interchange|gb|rail}} ({{rail-interchange|air}} <small>Trains to [[Gatwick Airport|Gatwick]] and [[London Luton Airport|Luton]]</small>) ({{rail-interchange|london|river}} <small>[[London Bridge City Pier]]</small>) || [[File:London Bridge tube stn entrance Borough High St.JPG|100px]] || Connects with [[Jubilee line]] and National Rail services.{{ref|map 36|map 36}}
|-
| [[Borough tube station|Borough]] || [[File:Borough station building.JPG|100px]] || rowspan="2" | 18 December 1890 || {{ref|map 37|map 37}}
|-
| [[Elephant & Castle tube station|Elephant & Castle]] {{rail-interchange|gb|rail}} {{rail-interchange|london|thameslink}} || [[File:Elephant & Castle stn south entrance.JPG|100px]] || Connects with [[Bakerloo line]] and National Rail services.{{ref|map 38|map 38}}
|}

====Kennington====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Branch !! Additional information
|-
| [[Kennington tube station|Kennington]] || [[File:Kennington station building.JPG|100px]] || 18 December 1890 || Charing Cross, Bank, Battersea and Morden branches{{efn|Morden and Battersea branches start immediately south of the station}} || The station has four platforms arranged in two pairs: one pair for northbound services to each central branch of the Northern line, the other pair for southbound services from each central branch. The junctions connecting the central branches to the southern branches are just south of Kennington station. Southbound trains from the Charing Cross branch can terminate at this station, which has a [[reversing loop]], or join either southern branch; southbound trains from the Bank branch can proceed onto the Morden branch but not the Battersea branch.{{ref|map 39|map 39}}
|}

====Battersea branch====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Additional information
|-
| [[Nine Elms tube station|Nine Elms]] {{access icon}} || [[File:Nine Elms Station, Platform Concourse (51497388149).jpg|100px]] || rowspan="2" | 20 September 2021 ||
|-
|[[Battersea Power Station tube station|Battersea Power Station]] {{access icon}}|| [[File:Battersea Power Station Station (51496672361).jpg|100px]] ||Terminus
|}

====Morden branch====
{| class="wikitable sortable"
|-
! Station !! class=unsortable|Image !! Opened !! Additional information
|-
| [[Oval tube station|Oval]] || [[File:Oval station building.JPG|100px]] || rowspan="2" | 18 December 1890 || {{ref|map 40|map 40}}
|-
| [[Stockwell tube station|Stockwell]] || [[File:Stockwell station building.JPG|100px]] || Connects with [[Victoria line]]. Original terminus until 1900, when the line was extended to Clapham Common. The station platforms were resited south of the original island platform. Formerly a depot existed here; it was branched off from the current southbound track. It is one of the eight stations that have a deep level air-raid shelter.{{ref|map 41|map 41}}
|-
| [[Clapham North tube station|Clapham North]] || [[File:Clapham North stn entrance.JPG|100px]] || rowspan="2" | 3 June 1900 || One of the two remaining stations to have an island platform underground. It is also one of the eight stations that have a deep level air-raid shelter.{{ref|map 42|map 42}}
|-
| [[Clapham Common tube station|Clapham Common]] || [[File:Clapham Common Tube Station Exterior - Oct 2007.jpg|100px]] || Terminus from 1900 to 1926. It is also one of the two remaining stations to have an island platform underground. It is also one of the eight stations that have a deep level air-raid shelter.{{ref|map 43|map 43}}
|-
| [[Clapham South tube station|Clapham South]] || [[File:ClaphamSouthTube.jpg|100px]] || 13 September 1926 || One of the eight stations that have a deep level air-raid shelter.{{ref|map 44|map 44}}
|-
| [[Balham station|Balham]] {{rail-interchange|gb|rail}} || [[File:Balham station.jpg|100px]] || 6 December 1926 || Connects with [[National Rail]] services.{{ref|map 45|map 45}}
|-
| [[Tooting Bec tube station|Tooting Bec]] || [[File:Tooting Bec stn west entrance.JPG|100px]] || rowspan="5" | 13 September 1926 || Opened as "Trinity Road"; renamed 1 October 1950.{{ref|map 46|map 46}}
|-
| [[Tooting Broadway tube station|Tooting Broadway]] || [[File:Tooting Broadway stn building.JPG|100px]] || Used as a terminus for some trains heading south.{{ref|map 47|map 47}}
|-
| [[Colliers Wood tube station|Colliers Wood]] || [[File:Colliers Wood stn entrance.JPG|100px]] || {{ref|map 48|map 48}}
|-
| [[South Wimbledon tube station|South Wimbledon]] || [[File:South Wimbledon stn entrance.JPG|100px]] || Opened as "South Wimbledon (Merton)". The suffix gradually fell out of use, but still can be seen on some platform signage.{{ref|map 49|map 49}}
|-
| [[Morden tube station|Morden]] {{access icon}} || [[File:Morden Tube Station.jpg|100px]] || Terminus.{{ref|map 50|map 50}}
|}

===Closed stations===
{{main|List of former and unopened London Underground stations}}

====Permanently closed stations====
* [[King William Street tube station|King William Street]] (closed 1900; replaced by [[Bank–Monument station|Bank]])
* [[City Road tube station|City Road]] (closed 1922)
* [[South Kentish Town tube station|South Kentish Town]] (closed 1924)
* [[North End tube station|North End]] (also known as "Bull & Bush". Never opened; work stopped 1906)

====Resited stations====
* [[Stockwell station|Stockwell]] – new platforms resited immediately to the south of its predecessor with the 1922–1924 upgrade of the line.
* [[London Bridge tube station|London Bridge]] – the northbound tunnel and platform converted into a concourse, and a new northbound tunnel and platform built in the late 1990s to increase the platform and circulation areas in preparation for the opening of the Jubilee line.<!-- Angel and Euston (City branch) were previously included in this sub-section but has been removed, as per the talk page. -->

====Abandoned plans====
=====Northern Heights stations not transferred from LNER=====
* [[Highgate tube station|Highgate]] – High-level only
* [[Stroud Green railway station|Stroud Green]]
* [[Crouch End railway station|Crouch End]]
* [[Cranley Gardens railway station|Cranley Gardens]]
* [[Muswell Hill railway station|Muswell Hill]]
* [[Alexandra Palace railway station (Muswell Hill branch)|Alexandra Palace]]
* [[Mill Hill (The Hale) railway station|Mill Hill (The Hale)]]

=====Bushey Extension stations not constructed=====
* [[Brockley Hill tube station|Brockley Hill]]
* [[Elstree South tube station|Elstree South]]
* [[Bushey Heath tube station|Bushey Heath]]

==Infrastructure==

===Rolling stock===
[[File:1995ts at Finchley Central.jpg|thumb|A [[High Barnet tube station|High Barnet]]-bound Northern line train arriving at [[Finchley Central tube station|Finchley Central]]|alt=]]
When the City & South London Railway opened, it was served by small [[electric locomotive]]s hauling wooden-bodied coaches.{{sfn|Horne|2009|p=11-12}} These, however, were deemed underpowered and the coaches had poor interior design, combined with lengthy dwell times at termini for turning the train around.{{sfn|Horne|2009|p=14}} Meanwhile, the "Hampstead Tube" used electric multiple units known as the Gate Stock or later the [[London Underground 1906 Stock|1906 Stock]].{{sfn|Horne|2009|p=25}} Both of these were replaced by the "[[London Underground Standard Stock|Standard Stock]]", a series of 1920s-built multiple units which also catered for the extension works to Edgware and Morden.{{sfn|Horne|2009|p=36}} 

As part of the New Works Programme, a total of 1121 cars of [[London Underground 1938 Stock|1938 Stock]] trains were built between 1938 and 1940 to equip the Northern line and its intended extensions with additional capacity, allowing a cascade of Standard Stock trains onto other lines to replace older rolling stock.{{sfn|Horne|2009|p=48-49}} These were supplemented with identical trailer and non-driving motor cars in 1949 which allowed a reorganisation of formations to ensure seven-car trains were kept throughout the fleet.{{sfn|Horne|2009|p=61}} 

From the late 1960s, the 1938 Stock began to show reliability issues and long-term industrial action at [[Acton Works]], which supplied the air compressors for them, led to cancellations of up to one-third of Northern line trains and short-formations becoming frequent.{{sfn|Horne|2009|p=62}} In prospect of the [[Piccadilly line]] extension to [[Heathrow Airport]] and a new fleet of trains for that line (coming in the form of the [[London Underground 1973 Stock|1973 Stock]]), the existing [[London Underground 1956 Stock|1956]] and [[London Underground 1959 Stock|1959 Stock]] trains were planned to be transferred to the Northern line, with thirty remaining 1938 Stock trains being refurbished to make up the shortfall.{{sfn|Horne|2009|p=62}} However, the relatively short timeframe of rolling stock cascades, owing to the imminent start of the Piccadilly line extension, meant that an equivalent number of new trains were instead ordered based on the [[Victoria line]]'s [[London Underground 1967 Stock|1967 Stock]], these becoming known as the [[London Underground 1972 Stock|1972 "Mark I" Stock]] which also entered service that year. The coexisting construction of the [[Jubilee line]] also prompted an additional 33 trains of 1972 "Mark II" Stock to run on the Northern line.<ref>{{Cite book |title=London Underground Owners' Workshop Manual |page=128 |author=Paul Moss |year=2014 |publisher=Haynes Publishing |ISBN=978-0-85733-369-8}}</ref>

Transfers of 1956 and 1959 Stock began in 1975,{{cn|date=May 2026}} 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 [[London Underground 1983 Stock|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.{{sfn|Horne|2009|p=68-69}} 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.{{sfn|Horne|2009|p=69}} 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.{{sfn|Horne|2009|p=69}}<ref>{{Cite web |url=https://www.lner.info/locos/Electric/tube.php |title=LNER-owned Northern Line Tube Stock |author=Richard Marsden}}</ref>

Following the introduction of the [[London Underground 1992 Stock|1992 Stock]] on the [[Central line (London Underground)|Central line]], some [[London Underground 1962 Stock|1962 Stock]] trains transferred to the Northern line in 1994 to replace the non-standard 1956 Stock trains.{{cn|date=May 2026}} 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.<ref>{{Cite web |url=http://www.trainweb.org/tubeprune/72%20tube%20stock.htm |title=London Underground 1972 Tube Stock |website=Trainweb Tubeprune |date=12 March 2003 |access-date=14 April 2026}}</ref> 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 [[London Underground 1995 Stock|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.{{cn|date=May 2026}}

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 gauge]]s used on the system. If the [[#Future|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,<ref>Abbot 2010, pp. 57–58.</ref> 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 line (London Underground)|Central]], [[Jubilee line|Jubilee]] and [[Piccadilly line]]s. Apart from the core central underground tunnels, part of the section between [[Hendon Central tube station|Hendon]] and [[Colindale tube station|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.<ref name="bicycle">{{cite web |url=http://www.tfl.gov.uk/assets/downloads/bicycle-tube-map.pdf |title=Bicycle on Tube map |date=June 2013 |publisher=Transport for London |access-date=5 April 2015 |archive-date=2 September 2013 |archive-url=https://web.archive.org/web/20130902230247/http://www.tfl.gov.uk/assets/downloads/bicycle-tube-map.pdf |url-status=live}}</ref> There are also time-based restrictions for the sections where bicycles are allowed.<ref name="bicycle" />

The tunnel from Morden to East Finchley via Bank, 17&nbsp;miles 528&nbsp;yards (27.841&nbsp;km),<ref name="linefact" /> was for a time the longest rail tunnel in the world. Other tunnels, including the [[Channel Tunnel]] that links the UK and France, are now longer.

===Depots===
The Northern line is serviced by four depots. The main one is at [[Golders Green]]{{ref|map 51|map 51}}, adjacent to Golders Green tube station, while the second, at [[Morden Depot|Morden]],{{ref|map 52|map 52}} is south of Morden tube station and is the larger of the two. The other two are at Edgware and Highgate. The Highgate depot is on the former LNER branch to Alexandra Palace. There was originally a depot at Stockwell, but this closed in 1915. There are sidings at High Barnet for stabling trains overnight.

==Potential splitting==
Since the 2000s, TfL has aspired to split the Northern line into two routes.<ref name=":02">{{cite CiteSeerX |date=November 2006|title=Transport 2025: Transport vision for a growing world city |citeseerx=10.1.1.135.5972|quote=A segregation of services would deliver simpler service patterns on the line. This will allow more trains to be run through both the West End and City branches – enabling 30tph services on the central London branches. This will provide roughly 25 per cent extra capacity and crowding relief on these busy sections. With the core infrastructure being capable of supporting these service patterns, the main requirements are some additional trains (and stabling) and station capacity improvements at Camden Town.}}</ref><ref>{{cite news |url=https://www.standard.co.uk/news/northern-line-service-divided-in-312m-bid-to-end-overcrowding-6468560.html |author=Lydall, Ross |title=Northern line service divided in £312m bid to end overcrowding |newspaper=Evening Standard|location=London |date=12 May 2010 |access-date=21 March 2013 |archive-date=15 December 2013 |archive-url=https://web.archive.org/web/20131215224824/http://www.standard.co.uk/news/northern-line-service-divided-in-312m-bid-to-end-overcrowding-6468560.html |url-status=live}}</ref> 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 tube station|Camden Town]] and [[Kennington tube station|Kennington]].<ref name="TwinPeaks">{{cite web|last1=Purley |first1=Pedantic of |title=Twin Peaks: Timetable Changes on the Northern Line|url=https://www.londonreconnections.com/2015/northern-line-timetable-for-the-future/|website=London Reconnections|date=14 January 2015|access-date=5 June 2017|archive-date=15 June 2017|archive-url=https://web.archive.org/web/20170615132515/http://www.londonreconnections.com/2015/northern-line-timetable-for-the-future/|url-status=live}}</ref> Completely segregating the routes could allow 36 trains an hour on all parts of the line, increasing capacity by around 25%.<ref name=":02" /><ref name="TwinPeaks"/>

TfL has already separated the Charing Cross and Bank branches during off-peak periods; however, four trains per hour still run to and from Morden via Charing Cross in the peak; the northern branches to Edgware and High Barnet cannot be separated until Camden Town station is upgraded to cope with the numbers of passengers changing trains.<ref name=":4">{{cite web|last1=Purley |first1=Pedantic of |date=6 May 2013|title=We Need To Talk About Camden: The Future of the Northern Line|url=https://www.londonreconnections.com/2013/we-need-to-talk-about-camden/|access-date=13 September 2021|website=London Reconnections|archive-date=23 September 2021|archive-url=https://web.archive.org/web/20210923125828/https://www.londonreconnections.com/2013/we-need-to-talk-about-camden/|url-status=live}}</ref> The extension to Battersea would allow the [[Charing Cross tube station|Charing Cross]] branch to terminate at Battersea Power Station.<ref>{{cite web|date=15 May 2010|title=Permanent split for the Northern line|url=https://www.yourlocalguardian.co.uk/news/8166289.permanent-split-for-the-northern-line/|url-status=live|access-date=13 September 2021|website=Your Local Guardian |archive-date=14 August 2020|archive-url=https://web.archive.org/web/20200814222805/https://www.yourlocalguardian.co.uk/news/8166289.permanent-split-for-the-northern-line/}}</ref><ref name=":412">{{cite web|date=4 August 2015|title=Plans to split Northern Line in two move forward another step|url=https://www.railtechnologymagazine.com/Rail-News/plans-to-split-northern-line-in-two-move-forward-another-step|url-status=live|access-date=13 September 2021|website=Rail Technology Magazine|archive-date=13 September 2021|archive-url=https://web.archive.org/web/20210913212544/https://www.railtechnologymagazine.com/Rail-News/plans-to-split-northern-line-in-two-move-forward-another-step}}</ref>

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.<ref name=":412"/><ref name="upcap12">{{cite web|date=2017|title=Improving capacity at Camden Town station|url=https://consultations.tfl.gov.uk/tube/camden-town-station-upgrade/|access-date=20 February 2018|publisher=Transport for London|archive-date=21 February 2018|archive-url=https://web.archive.org/web/20180221100254/https://consultations.tfl.gov.uk/tube/camden-town-station-upgrade/|url-status=live}} Detailed report, with updated timeline etc.</ref><ref name=":4" /> In 2005, London Underground failed to secure planning permission for a comprehensive upgrade plan for Camden Town tube station that would have involved demolition of the existing station entrance and several other surface-level buildings, all within a [[Conservation area (United Kingdom)|conservation area]].<ref>{{cite web|date=25 January 2006|title=Camden Town Redevelopment|url=http://www.alwaystouchout.com/project/62|access-date=30 June 2008|publisher=Alwaystouchout.com|archive-date=11 November 2007|archive-url=https://web.archive.org/web/20071111081104/http://www.alwaystouchout.com/project/62|url-status=dead}}</ref><ref name="2ndTimeLucky">{{cite web|last1=Bull|first1=John|date=14 October 2015|title=Second Time Lucky: Rebuilding Camden Town Station|url=https://www.londonreconnections.com/2015/second-time-lucky-rebuilding-camden-town-station/|website=London Reconnections|access-date=5 June 2017|archive-date=28 June 2017|archive-url=https://web.archive.org/web/20170628175351/http://www.londonreconnections.com/2015/second-time-lucky-rebuilding-camden-town-station/|url-status=live}}</ref> 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]].<ref name="upcap12"/> In 2018, plans to upgrade and rebuild Camden Town station were placed indefinitely on hold, due to TfL's financial situation.<ref>{{cite news |last=Topham |first=Gwyn |date=11 December 2018 |title=Major tube upgrades shelved as TfL struggles to balance books |work=The Guardian |location=London |url=https://www.theguardian.com/uk-news/2018/dec/11/major-tube-upgrades-shelved-as-tfl-struggles-to-balance-books |access-date=26 January 2020 |archive-date=26 December 2019 |archive-url=https://web.archive.org/web/20191226092007/https://www.theguardian.com/uk-news/2018/dec/11/major-tube-upgrades-shelved-as-tfl-struggles-to-balance-books |url-status=live}}</ref> {{As of|2024}}, 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.<ref name="f763">{{cite web |last=Cooke |first=Alex |date=14 April 2024 |title=TfL still 'aspires' to split Tube line to increase capacity by 20k |url=https://www.mylondon.news/news/transport/tfl-northern-line-london-underground-28980969 |access-date=16 March 2025 |website=My London}}</ref>

==Incidents and accidents==
In October 2003, a train derailed at [[Camden Town tube station|Camden Town]].<ref>{{cite news |date=19 October 2003 |title=Second Tube train derailed |publisher=BBC News |url=https://news.bbc.co.uk/2/hi/uk_news/england/london/3204794.stm |access-date=27 May 2020 |archive-date=25 July 2020 |archive-url=https://web.archive.org/web/20200725100727/http://news.bbc.co.uk/2/hi/uk_news/england/london/3204794.stm |url-status=live}}</ref> 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 tube station|Chancery Lane]] earlier in 2003.<ref>{{cite news |date=25 January 2003 |title=Thirty hurt after Tube crash |publisher=BBC News |url=https://news.bbc.co.uk/1/hi/england/2694361.stm |access-date=27 May 2020 |archive-date=30 April 2020 |archive-url=https://web.archive.org/web/20200430185255/http://news.bbc.co.uk/2/hi/uk_news/england/2694361.stm |url-status=live}}</ref> 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.<ref>{{cite magazine |title=Track design flaws may have led to Camden Town Tube derailment |url=https://www.newcivilengineer.com/archive/track-design-flaws-may-have-led-to-camden-town-tube-derailment-04-12-2003/ |date=4 December 2003 |magazine=New Civil Engineer |access-date=27 May 2020}}</ref>

In August 2010, a defective [[Railgrinder|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 tube station|Archway station]], the defective train became detached and ran driverless until coming to a stop at an incline near [[Warren Street tube station|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.<ref>{{cite news |date=13 August 2010 |title=Runaway train on London Tube's Northern Line |publisher=BBC News |url=https://www.bbc.co.uk/news/uk-england-10964766 |access-date=18 August 2010 |archive-date=17 August 2010 |archive-url=https://web.archive.org/web/20100817235330/http://www.bbc.co.uk/news/uk-england-10964766 |url-status=live}}</ref><ref>{{cite tech report |title=Runaway of an engineering train from Highgate 13 August 2010 |number=09-2011 |institution=RAIB |year=2011}}</ref>

==In popular culture==
* In his [[debut novel]] ''[[Ghostwritten (novel)|Ghostwritten]]'', [[David Mitchell (author)|David Mitchell]] characterises the Northern line as "the psycho of the family".<ref>{{cite web|url=http://www.beamsandstruts.com/bits-a-pieces/item/530-david-mitchell|title=Literary Excerpt: David Mitchell and the Character of the London Underground Lines|author=TJ Dawe|access-date=31 March 2014|archive-date=2 April 2015|archive-url=https://web.archive.org/web/20150402181602/http://www.beamsandstruts.com/bits-a-pieces/item/530-david-mitchell|url-status=live}}</ref>
* The [[Bloc Party]] song "Waiting For the 7.18" references the Northern line as "the loudest".<ref>{{cite web|url=http://www.blocparty.net/waitingforthe718.html|title=BlocParty.net – Waiting for the 7.18|archive-url=https://web.archive.org/web/20130415094528/http://www.blocparty.net/waitingforthe718.html|archive-date=15 April 2013}}</ref>
* 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.<ref>{{cite web |url= http://www.penguin.co.uk/books/a-northern-line-minute/9781846145315/ |title=A Northern Line Minute, The Northern Line by William Leith |publisher=Penguin |date=7 March 2013 |archive-url= https://web.archive.org/web/20150403093024/https://www.penguin.co.uk/books/a-northern-line-minute/9781846145315/ |archive-date=3 April 2015 |access-date=28 August 2017}}</ref>
* The [[New Vaudeville Band|New Vaudeville Band's]] 1967 song "Finchley Central" ("On Tour" in the US) mentions several stations on the line.<ref>{{cite web |author1=Alan Charles Klein |author2=Geoffrey Stephens |title=New Vaudeville Band: Finchley Central |url=https://lyrics.lyricfind.com/lyrics/new-vaudeville-band-finchley-central |website=LyricFind |publisher=Peermusic Publishing |access-date=15 June 2025 |date=1967}}</ref>
* The [[Nick Drake]] song "Parasite" references the Northern Line.<ref>{{cite web|url=http://www.nickdrake.com/parasite_lyrics.html|title=Parasite|access-date=9 November 2015|archive-date=24 October 2015|archive-url=https://web.archive.org/web/20151024091819/http://www.nickdrake.com/parasite_lyrics.html|url-status=live}}</ref>
* 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."<ref>{{cite web|url=https://genius.com/Robyn-hitchcock-fifty-two-stations-lyrics|title=Fifty Two Stations|access-date=13 August 2018|archive-date=14 August 2018|archive-url=https://web.archive.org/web/20180814002027/https://genius.com/Robyn-hitchcock-fifty-two-stations-lyrics|url-status=live}}</ref>
* The 2021 [[Maisie Peters]] song "Elvis Song" begins, "Cold bench on a platform/Last train on the Northern Line."<ref>{{cite web|url=https://genius.com/maisie-peters-elvis-song-lyrics|title=Elvis Song|access-date=2 July 2024|archive-date=20 June 2023|archive-url=https://web.archive.org/web/20230620232218/https://genius.com/Maisie-peters-elvis-song-lyrics|url-status=live}}</ref>

==Maps==
{{div col|colwidth=25em|small=yes}}
*{{note|map 1|map 1}}High Barnet – {{coord|51|39|02|N|000|11|39|W|region:GB_type:railwaystation|name=01 – High Barnet tube station}}
*{{note|map 2|map 2}}Totteridge & Whetstone – {{coord|51|37|50|N|000|10|45|W|region:GB_type:railwaystation|name=02 – Totteridge & Whetstone tube station}}
*{{note|map 3|map 3}}Woodside Park – {{coord|51|37|05|N|000|11|08|W|region:GB_type:railwaystation|name=03 – Woodside Park tube station}}
*{{note|map 4|map 4}}West Finchley – {{coord|51|36|34|N|000|11|18|W|region:GB_type:railwaystation|name=04 – West Finchley tube station}}
*{{note|map 5|map 5}}Mill Hill East – {{coord|51|36|30|N|000|12|37|W|region:GB_type:railwaystation|name=05 – Mill Hill East tube station}}
*{{note|map 6|map 6}}Finchley Central – {{coord|51|36|04|N|000|11|33|W|region:GB_type:railwaystation|name=06 – Finchley Central tube station}}
*{{note|map 7|map 7}}East Finchley – {{coord|51|35|14|N|000|09|54|W|region:GB_type:railwaystation|name=07 – East Finchley tube station}}
*{{note|map 8|map 8}}Highgate – {{coord|51|34|40|N|000|08|45|W|region:GB_type:railwaystation|name=08 – Highgate tube station}}
*{{note|map 9|map 9}}Archway – {{coord|51|33|56|N|000|08|06|W|region:GB_type:railwaystation|name=09 – Archway tube station}}
*{{note|map 10|map 10}}Tufnell Park – {{coord|51|33|24|N|000|08|17|W|region:GB_type:railwaystation|name=10 – Tufnell Park tube station}}
*{{note|map 11|map 11}}Kentish Town – {{coord|51|33|01|N|000|08|26|W|region:GB_type:railwaystation|name=11 – Kentish Town stationq}}
*{{note|map 12|map 12}}Edgware – {{coord|51|36|50|N|000|16|30|W|region:GB_type:railwaystation|name=12 – Edgware tube station}}
*{{note|map 13|map 13}}Burnt Oak – {{coord|51|36|10|N|000|15|50|W|region:GB_type:railwaystation|name=13 – Burnt Oak tube station}}
*{{note|map 14|map 14}}Colindale – {{coord|51|35|44|N|000|15|00|W|region:GB_type:railwaystation|name=14 – Colindale tube station}}
*{{note|map 15|map 15}}Hendon Central – {{coord|51|34|59|N|000|13|34|W|region:GB_type:railwaystation|name=15 – Hendon Central tube station}}
*{{note|map 16|map 16}}Brent Cross – {{coord|51|34|36|N|000|12|49|W|region:GB_type:railwaystation|name=16 – Brent Cross tube station}}
*{{note|map 17|map 17}}Golders Green – {{coord|51|34|19|N|000|11|38|W|region:GB_type:railwaystation|name=17 – Golders Green tube station}}
*{{note|map 18|map 18}}Hampstead – {{coord|51|33|25|N|000|10|42|W|region:GB_type:railwaystation|name=18 – Hampstead tube station}}
*{{note|map 19|map 19}}Belsize Park – {{coord|51|33|01|N|000|09|52|W|region:GB_type:railwaystation|name=19 – Belsize Park tube station}}
*{{note|map 20|map 20}}Chalk Farm – {{coord|51|32|39|N|000|09|12|W|region:GB_type:railwaystation|name=20 – Chalk Farm tube station}}
*{{note|map 21|map 21}}Camden Town – {{coord|51|32|22|N|000|08|34|W|region:GB_type:railwaystation|name=21 – Camden Town tube station}}
*{{note|map 22|map 22}}Mornington Crescent – {{coord|51|32|04|N|000|08|19|W|region:GB_type:railwaystation|name=22 – Mornington Crescent tube station}}
*{{note|map 23|map 23}}Euston – {{coord|51|31|42|N|000|07|59|W|region:GB_type:railwaystation|name=23 – Euston tube station}}
*{{note|map 24|map 24}}Warren Street – {{coord|51|31|29|N|000|08|18|W|region:GB_type:railwaystation|name=24 – Warren Street tube station}}
*{{note|map 25|map 25}}Goodge Street – {{coord|51|31|15|N|000|08|04|W|region:GB_type:railwaystation|name=25 – Goodge Street tube station}}
*{{note|map 26|map 26}}Tottenham Court Road – {{coord|51|30|58|N|000|07|51|W|region:GB_type:railwaystation|name=26 – Tottenham Court Road tube station}}
*{{note|map 27|map 27}}Leicester Square – {{coord|51|30|41|N|000|07|41|W|region:GB_type:railwaystation|name=27 – Leicester Square tube station}}
*{{note|map 28|map 28}}Charing Cross – {{coord|51|30|29|N|000|07|29|W|region:GB_type:railwaystation|name=28 – Charing Cross tube station}}
*{{note|map 29|map 29}}Embankment – {{coord|51|30|25|N|000|07|19|W|region:GB_type:railwaystation|name=29 – Embankment tube station}}
*{{note|map 30|map 30}}Waterloo – {{coord|51|30|09|N|000|06|47|W|region:GB_type:railwaystation|name=30 – Waterloo tube station}}
*{{note|map 31|map 31}}King's Cross St Pancras – {{coord|51|31|49|N|000|07|27|W|region:GB_type:railwaystation|name=31 – King's Cross St Pancras tube station}}
*{{note|map 32|map 32}}Angel – {{coord|51|31|55|N|000|06|22|W|region:GB_type:railwaystation|name=32 – Angel tube station}}
*{{note|map 33|map 33}}Old Street – {{coord|51|31|33|N|000|05|14|W|region:GB_type:railwaystation|name=33 – Old Street station}}
*{{note|map 34|map 34}}Moorgate – {{coord|51|31|07|N|000|05|19|W|region:GB_type:railwaystation|name=34 – Moorgate station}}
*{{note|map 35|map 35}}Bank-Monument – {{coord|51|30|47|N|000|05|17|W|region:GB_type:railwaystation|name=35 – Bank–Monument station}}
*{{note|map 36|map 36}}London Bridge – {{coord|51|30|18|N|000|05|10|W|region:GB_type:railwaystation|name=36 – London Bridge station}}
*{{note|map 37|map 37}}Borough – {{coord|51|30|04|N|000|05|35|W|region:GB_type:railwaystation|name=37 – Borough tube station}}
*{{note|map 38|map 38}}Elephant & Castle – {{coord|51|29|40|N|000|05|59|W|region:GB_type:railwaystation|name=38 – Elephant & Castle tube station}}
*{{note|map 39|map 39}}Kennington – {{coord|51|29|19|N|000|06|20|W|region:GB_type:railwaystation|name=39 – Kennington tube station}}
*{{note|map 40|map 40}}Oval – {{coord|51|28|55|N|000|06|45|W|region:GB_type:railwaystation|name=40 – Oval tube station}}
*{{note|map 41|map 41}}Stockwell – {{coord|51|28|21|N|000|07|20|W|region:GB_type:railwaystation|name=41 – Stockwell tube station}}
*{{note|map 42|map 42}}Clapham North – {{coord|51|27|54|N|000|07|48|W|region:GB_type:railwaystation|name=42 – Clapham North tube station}}
*{{note|map 43|map 43}}Clapham Common – {{coord|51|27|42|N|000|08|19|W|region:GB_type:railwaystation|name=43 – Clapham Common tube station}}
*{{note|map 44|map 44}}Clapham South – {{coord|51|27|10|N|000|08|51|W|region:GB_type:railwaystation|name=44 – Clapham South tube station}}
*{{note|map 45|map 45}}Balham – {{coord|51|26|33|N|000|09|07|W|region:GB_type:railwaystation|name=45 – Balham station}}
*{{note|map 46|map 46}}Tooting Bec – {{coord|51|26|09|N|000|09|35|W|region:GB_type:railwaystation|name=46 – Tooting Bec tube station}}
*{{note|map 47|map 47}}Tooting Broadway – {{coord|51|25|40|N|000|10|06|W|region:GB_type:railwaystation|name=47 – Tooting Broadway tube station}}
*{{note|map 48|map 48}}Colliers Wood – {{coord|51|25|06|N|000|10|42|W|region:GB_type:railwaystation|name=48 – Colliers Wood tube station}}
*{{note|map 49|map 49}}South Wimbledon – {{coord|51|24|56|N|000|11|31|W|region:GB_type:railwaystation|name=49 – South Wimbledon tube station}}
*{{note|map 50|map 50}}Morden – {{coord|51|24|08|N|000|11|42|W|region:GB_type:railwaystation|name=50 – Morden tube station}}
*{{note|map 51|map 51}}Golders Green depot – {{coord|51|34|22|N|000|11|35|W|region:GB_type:railwaystation|name=51 – Golders Green depot}}
*{{note|map 52|map 52}}Morden depot – {{coord|51|23|51|N|000|11|49|W|region:GB_type:railwaystation|name=52 – Morden depot}}
{{div col end}}
{{GeoGroup}}

==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===
{{notelist}}

===Citations===
{{reflist}}

===Bibliography===
{{refbegin}}
* {{cite journal |last=Abbott |first=James |date=February 2010 |title=Northern Line split planned |journal=[[Modern Railways]] |volume=67 |issue=737 |issn=0026-8356}}
* {{cite book |last1=Day |first1=John R |last2=Reed |first2=John |orig-date=1963 |year=2010 |edition=11th |title=The Story of London's Underground |publisher=Capital Transport |isbn=978-1-85414-341-9}}
* {{cite book |last=Badsey-Ellis |first=Antony |title=London's Lost Tube Schemes |year=2005 |publisher=Capital Transport |isbn=185414-293-3}}
* {{cite book |last=Beard |first=Tony |title=By Tube Beyond Edgware |publisher=Capital Transport |year=2002 |isbn=978-1-85414-246-7}}
* {{cite book |last1=Blake |first1=Jim |first2=Jonathan |last2=James |title=Northern Wastes: Scandal of the Uncompleted Northern Line |publisher=North London Transport Society |location=London |year=1993 |isbn=978-0-946383-04-7}}
* {{cite book |last=Demuth |first=Tim |title=The Spread of London's Underground |edition=2 |year=2004 |location=London |publisher=Capital Transport Publishing |isbn=978-1-85414-277-1}}
* {{cite book |last1=Graves |first1=Robert |last2=Hodge |first2=Alan |author-link1=Robert Graves |author-link2=Alan Hodge |title=[[The Long Week-End]] |year=1940 |publisher=[[Faber & Faber]]}}
* {{cite book |last=Horne |first=Mike |title=Northern Line: A Short History |publisher=Douglas Rose |location=London |year=1987 |isbn=978-1-870354-00-4}}
* {{cite book |last=Horne |first=Mike |title=The Northern Line: An Illustrated History |publisher=Capital Transport Publishing |edition=3 |location=London |year=2009 |isbn=978-1-85414-326-6}}
* {{cite book |last=Lee |first=Charles Edward |title=Northern Line |publisher=London Transport |location=London |year=1973 |isbn=978-0-85329-044-5}}
* {{cite book |last=Lee |first=Charles Edward |title=Sixty Years of the Northern |publisher=London Transport |location=London |year=1967 |oclc=505166556}}
* {{cite book |last=Lee |first=Charles Edward |title=Fifty Years of the Hampstead Tube |publisher=London Transport |location=London |year=1957 |oclc=23376254}}
* {{cite book |last=Murphy |first=Simon |title=Northern Line Extensions: Golders Green to Edgware, 1922–24 |publisher=The History Press |location=London |year=2005 |isbn=978-0-7524-3498-8}}
* {{cite book |last=Rose |first=Douglas |title=The London Underground, A Diagrammatic History |year=2016 |orig-date=1980 |edition=9th |publisher=Douglas Rose/Capital Transport |isbn=978-1-85414-404-1}}
* {{cite book |last=Wolmar |first=Christian |author-link=Christian Wolmar |title=The Subterranean Railway: How the London Underground Was Built and How It Changed the City Forever |publisher=Atlantic Books |orig-date=2004 |year=2005 |isbn=978-1-84354-023-6 |location=London}}
{{refend}}

==External links==
{{Commons category|Northern Line}}
{{Attached KML|display=title,inline}}
*{{Official website}}
* [https://web.archive.org/web/20110707160249/http://www.architecture.com/LibraryDrawingsAndPhotographs/Exhibitionsandloans/VARIBAArchitecturePartnershipexhibitions/UndergroundJourneys/UndergroundJourneys.aspx Architectural history of London Underground during 1920-30s] from the [[Royal Institute of British Architects]]
** [https://web.archive.org/web/20110707161133/http://www.architecture.com/LibraryDrawingsAndPhotographs/Exhibitionsandloans/VARIBAArchitecturePartnershipexhibitions/UndergroundJourneys/FitnessforPurpose/OldStreet.aspx Old Street, Angel and Stockwell stations]
** [https://web.archive.org/web/20110504024751/http://www.architecture.com/LibraryDrawingsAndPhotographs/Exhibitionsandloans/VARIBAArchitecturePartnershipexhibitions/UndergroundJourneys/MovingUnderground/MovingUnderground.aspx South Clapham, Tooting Bec and South Wimbledon]
{{maplink|display=title|type=line|from=Northern line.map}}
{{Northern line navbox}}

{{DEFAULTSORT:Northern line}}
[[Category:London Underground lines]]
[[Category:Automatic London Underground lines]]
[[Category:Railway lines opened in 1890]]
[[Category:Transport in the London Borough of Barnet]]
[[Category:Transport in the London Borough of Haringey]]
[[Category:Transport in the London Borough of Islington]]
[[Category:Transport in the London Borough of Camden]]
[[Category:Transport in the City of Westminster]]
[[Category:Transport in the City of London]]
[[Category:Transport in the London Borough of Southwark]]
[[Category:Transport in the London Borough of Lambeth]]
[[Category:Transport in the London Borough of Wandsworth]]
[[Category:Transport in the London Borough of Merton]]
[[Category:Tunnels underneath the River Thames]]
[[Category:Standard gauge railways in London]]
[[Category:Articles containing video clips]]
[[Category:1890 establishments in England]]