Editing Northern line (section)

==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 (with [[Peter W. Barlow]]) 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 (Northern Heights and Battersea extensions not shown)]]

The CCE&HR (commonly known as the "Hampstead Tube") was opened in 1907 and ran from [[Charing Cross tube station|Charing Cross]] (known for many years as Strand) via Euston and a junction at [[Camden Town tube station|Camden Town]] to [[Golders Green tube station|Golders Green]] and Highgate (now known as [[Archway tube station|Archway]]).{{sfn|Horne|2009|p=26}}{{sfn|Rose|2016}} It was extended south by one stop to [[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.{{sfn|Wolmar|2005|p=205}}

===Integration===
During the early 1920s a series of works were carried out which involved connecting 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 station and the CCE&HR's station at Camden Town, had originally been planned in 1912 but was delayed by the 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 the main line station there and the [[Bakerloo line]]. 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}}

===Extensions===
In conjunction with the works to integrate the two lines, two major extensions were undertaken: northwards to [[Edgware]] in [[Middlesex]] (now in the [[London Borough of Barnet]]) and southwards to [[Morden]] in [[Surrey]] (then in the [[Merton and Morden Urban District]], but now in the [[London Borough of Merton]]).

====Edgware Extension====
The Edgware extension used plans dating back to 1901 for the [[Charing Cross, Euston and Hampstead Railway#Hampstead Heath controversy|Edgware and Hampstead Railway]] (E&HR)<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 Edgware in two stages: 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 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]], head of the Underground's Architects Office, stimulating the rapid northward expansion of suburban developments in the following years.{{sfn|Day|Reed|2010|p=91}}

====Morden Extension====
The engineering of the Morden extension of the C&SLR from Clapham Common to Morden was more demanding; it runs in tunnels to a point just north of [[Morden tube station|Morden station]] which was constructed in a cutting. The line then goes under the wide station forecourt and public road outside the station to the depot. The extension was initially [[Sutton Underground Line Proposal|planned]] to continue to [[Sutton, London|Sutton]]<ref name=gazette_3>{{London Gazette |issue=32770 |date=24 November 1922 |pages=8314–8315}}</ref> over part of the route for the unbuilt [[Wimbledon and Sutton Railway]] (in which the UERL held a stake) but agreements were made with [[Southern Railway (Great Britain)|Southern Railway]] to end the extension at Morden. Southern Railway built the surface line from Wimbledon to Sutton in the 1930s via South Merton and St. Helier.{{#tag:ref|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 (Surrey) railway station|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.|group="nb"}} The tube extension itself opened in 1926 with seven new stations all designed by [[Charles Holden]] in a modern style. Originally Stanley Heaps was to design the stations, but after seeing the designs [[Frank Pick]] (Assistant Joint Manager of the UERL) decided that Holden should take over the project.<ref>{{cite web |title=Underground Journeys: Moving Underground |url=http://www.architecture.com/LibraryDrawingsAndPhotographs/Exhibitionsandloans/VARIBAArchitecturePartnershipexhibitions/UndergroundJourneys/MovingUnderground/MovingUnderground.aspx |work=architecture.com |publisher=[[Royal Institute of British Architects]] |access-date=20 February 2011 |archive-url=https://web.archive.org/web/20110504024751/http://www.architecture.com/LibraryDrawingsAndPhotographs/Exhibitionsandloans/VARIBAArchitecturePartnershipexhibitions/UndergroundJourneys/MovingUnderground/MovingUnderground.aspx |archive-date=4 May 2011}}</ref>

With the exception of Morden and [[Clapham South tube station|Clapham South]], where more land was available, the new stations were built on confined corner sites at main road junctions in areas that had been already developed. Holden made good use of this limited space and designed striking buildings. The street-level structures are of white [[Portland stone]] with tall double-height ticket halls, with the London Underground roundel made up in coloured glass panels in large glazed screens. The stone columns framing the glass screens are surmounted by a capital formed as a three-dimensional version of the roundel. The large expanses of glass above the entrances ensure that the ticket halls are bright and lit from within at night, creating a welcoming feel.<ref>{{cite web |title=Underground Journeys: South Wimbledon |url=http://www.architecture.com/LibraryDrawingsAndPhotographs/Exhibitionsandloans/VARIBAArchitecturePartnershipexhibitions/UndergroundJourneys/MovingUnderground/SouthWimbledon.aspx |work=architecture.com |publisher=[[Royal Institute of British Architects]] |access-date=20 February 2011 |archive-url=https://web.archive.org/web/20110707161011/http://www.architecture.com/LibraryDrawingsAndPhotographs/Exhibitionsandloans/VARIBAArchitecturePartnershipexhibitions/UndergroundJourneys/MovingUnderground/SouthWimbledon.aspx |archive-date=7 July 2011}}</ref> The first and last new stations on the extension, Clapham South and Morden, include a parade of shops and were designed with structures capable of being built above (like many of the earlier [[central London]] stations). Clapham South was extended upwards soon after its construction with a block of apartments; Morden was extended upwards in the 1960s with a block of offices. All the stations on the extension, except Morden itself, are Grade II [[listed building]]s.

===Great Northern & City Railway===
After the UERL and the [[Metropolitan Railway]] became part of the new unified [[London Passenger Transport Board]] in 1933, the MR's subsidiary the [[Northern City Line|Great Northern & City Railway]] became part of the Underground as the Northern City Line. It ran underground from Moorgate to [[Finsbury Park station|Finsbury Park]]. In preparation for the Northern Heights Plan it was operated as part of the Northern line, although it was never connected to the rest of the line.

===Naming===
The resulting line became known as the Morden–Edgware line, although a number of alternative names were also mooted in the fashion of the contraction of Baker Street & Waterloo Railway to "Bakerloo", such as "Edgmor", "Mordenware", "Medgeway" and "Edgmorden".{{sfn|Wolmar|2005|p=225}} It was eventually named the ''Northern line'' from 28 August 1937,<ref>Rails through the Clay; Croome & Jackson; London; 2nd ed; 1993; p228</ref> reflecting the planned addition of the Northern Heights lines.<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>

==={{anchor|The Northern Heights plan}} Northern Heights plan===
[[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]]
<!-- 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}}
In June 1935 the LPTB announced the [[New Works Programme]], an ambitious plan to expand the Underground network which included the integration of a complex of existing [[London and North Eastern Railway]] (LNER) lines north of [[Highgate]] through the Northern Heights. These lines, built in the 1860s and 1870s by the [[Edgware, Highgate and London Railway]] (EH&LR) and its successors, ran 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 line taken over would be extended beyond Edgware to [[Brockley Hill tube station|Brockley Hill]], [[Elstree South tube station|Elstree South]] and [[Bushey Heath tube station|Bushey Heath]] with a new depot at [[Aldenham Works|Aldenham]]. The extension's route was that planned for the unbuilt [[Watford and Edgware Railway]] (W&ER), using rights obtained from the earlier purchase of the W&ER (which had long intended an extension of the EH&LR Edgware route towards [[Watford]]). This also provided the potential for further extension in the future; [[Bushey]]'s town planners reserved space in Bushey village for a future station and Bushey Heath station's design was revised several times to ensure this option would remain available in the future.

The project involved [[Railway electrification in Great Britain|electrification]] of the surface lines (operated by steam trains at the time), the doubling of the original single-line section between [[Finchley Central tube station|Finchley Central]] and the proposed junction with the Edgware branch of the Northern line, and the construction of three new linking sections of track: a connection between Northern City Line and Finsbury Park station on the surface; an extension from Archway to the LNER line near [[East Finchley tube station|East Finchley]] via new deep-level platforms below [[Highgate tube station|Highgate station]]; and a short diversion from just before the LNER's Edgware station to the Underground's station of the same name.

====Intended service levels====
The peak-hour service pattern was to be 21 trains an hour each way on the High Barnet branch north of Camden Town, 14 of them via the Charing Cross branch and seven via the Bank branch. 14 would have continued on beyond Finchley Central, seven each on the High Barnet and Edgware branches. An additional seven trains an hour would have served the High Barnet branch but continued via Highgate High-Level and Finsbury Park to Moorgate, a slightly shorter route to the city. It does not seem to have been intended to run through trains to the ex-Northern City branch from Edgware via Finchley Central. Seven trains an hour would have served the Alexandra Palace branch, to/from Moorgate via Highgate High-Level. In addition to the 14 through trains described the ex-Northern City branch would have had 14 four-car shuttle trains an hour.

====Progress of works====
Work began in the late 1930s and was in progress on all fronts by the outbreak of the [[World War II|Second World War]]. The tunnelling northwards from the original Highgate station (now [[Archway tube station|Archway]]) had been completed, and the service to the rebuilt surface station at [[East Finchley tube station|East Finchley]] started on 3 July 1939 but without the opening of the intermediate (new) Highgate Station at the site of the LNER's station of the same name. Further progress was disrupted by the start of the war; however enough development had been made to complete the electrification of the [[High Barnet tube station|High Barnet]] branch onwards from East Finchley (over which tube services started on 14 April 1940) and the new deep-level [[Highgate tube station|Highgate]] station opened on 19 January 1941. The single track LNER line to Edgware was electrified as far as [[Mill Hill East tube station|Mill Hill East]], including the [[Dollis Brook Viaduct]], opening as a tube service on 18 May 1941 to serve the barracks there thus forming the Northern line as it is today. The new depot at Aldenham had already been built and was used to build [[Handley Page Halifax|Halifax]] bombers. Work on the other elements of the plan was suspended late in 1939.

Work on the extension from Edgware to Bushey Heath including work on a viaduct and a tunnel started in June 1939, but was stopped after war broke out.{{sfn|Beard|2002|pp=90–92}} After the war, the area beyond Edgware was made part of the [[Metropolitan Green Belt]], largely preventing the anticipated residential development in the area, and the potential demand for services from Bushey Heath thus vanished. Passenger numbers also dropped on the then-[[British Rail|BR]]'s Mill Hill and Alexandra Palace branches, so it was useless to electrify them. Available funds were directed towards completing the eastern extension of the [[Central line (London Underground)|Central line]] instead, and the Northern Heights plan was dropped on 9 February 1954. Aldenham depot was converted into an overhaul facility for buses.

The implemented service from High Barnet branch gave good access both to the [[West End of London|West End]] and the [[City of London|City]]. This appears to have undermined traffic on the Alexandra Palace branch, still run with steam haulage to [[King's Cross St Pancras tube station|Kings Cross]] via Finsbury Park, as Highgate (low-level) was but a short bus ride away and car traffic was much lighter than it would become later. Consequently, the line from Finsbury Park to Muswell Hill and Alexandra Palace via the surface platforms at Highgate was closed altogether to passenger traffic in 1954.{{citation needed|date=May 2020}} This contrasts with the decision to electrify the Epping-Ongar branch of the Central line, another remnant of the New Works programme, run as a tube-train shuttle from 1957. A local pressure group, the Muswell Hill Metro Group, campaigns to reopen this route as a light-rail service.{{citation needed|date=May 2020}} So far there is no sign of movement on this issue: the route, now the [[Parkland Walk]], is highly valued by walkers and cyclists, and suggestions in the 1990s that it could, in part, become a road were met with fierce opposition.{{citation needed|date=May 2020}} Another pressure group has proposed using the track bed further north, as part of the [[North and West London Light Railway]].{{citation needed|date=May 2020}} The connection between [[Drayton Park railway station|Drayton Park]] and the surface platforms at Finsbury Park was opened in 1976, when the Northern City Line became part of [[British Rail]].

=== 1990s refurbishment and upgrade ===
[[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 the 1980s, a southern extension of the line to [[Peckham]] was proposed, as part of a review of potential extensions of Underground lines. The proposal was not proceeded with.<ref>{{cite web|date=1988|title=Strategic Review 1988 – New Lines and Extensions – Northern Line Southern Extension |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>

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=http://news.bbc.co.uk/1/hi/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>