Northern City Line

The Northern City Line is a commuter line in England, which runs from London Moorgate to Finsbury Park in London with services running beyond. It is part of the Great Northern Route services, and operates as the south-eastern branch of the East Coast Main Line (ECML). It is underground from Moorgate to Drayton Park in Highbury, from which point it runs in a cutting until joining the ECML south of Finsbury Park. Its stations span northern inner districts of Greater London southwards to the City of London, the UK's main financial centre. Since December 2015, its service timetable has been extended to run into the late evenings and at weekends,[2] meeting a new franchise commitment for a minimum of six trains per hour until 23:59 on weekdays and four trains per hour at weekends.[3]

Northern City Line
A Class 313 train departing Moorgate
TypeCommuter rail, Suburban rail
SystemNational Rail
LocaleGreater London
TerminiFinsbury Park
London Moorgate
OwnerNetwork Rail
Operator(s)Great Northern
Rolling stockClass 717 "Desiro City"
Number of tracksTwo
Track gauge1,435 mm (4 ft 8 12 in) standard gauge
Loading gaugeW6[1]
Electrification25 kV 50 Hz AC OHLE (Drayton Park and north)
750 V DC third rail (Drayton Park and south)
Northern City Line
LNER Alexandra Palace branch
(conversion started but abandoned)
Muswell Hill
Cranley Gardens
Highgate depot
Crouch End
Stroud Green
Finsbury Park
Finsbury Park Junction
Holloway Junction
Canonbury curve
Drayton Park
Highbury & Islington
North London and East London lines
via Canonbury
Essex Road
Old Street
Lothbury proposed but not built

The official name for this line is the Moorgate Line,[4][5] but it is rarely referred to as this because of the confusion with the Widened Lines route which runs between Kentish Town and Farringdon. Until recently, it also served Moorgate surface-level station on the London Midland Region.[6][7] The Northern City Line's name is derived from the fact that it was formerly a London Underground line, where it was described or managed as part of both the Metropolitan and Northern lines (sometimes as the "Highbury Branch"), although never connected to either. Built as an isolated route with a northern terminus at Finsbury Park, reconstruction connected it to the British Rail network in 1976 and began its modern service pattern. One of London's deep-level railways, the Northern City is unlike the others in being owned by Network Rail and served by commuter trains operated by Great Northern from Moorgate to Finsbury Park and onwards to Hertfordshire.

In 2016, it was proposed that all London rail services should be transferred to Transport for London to create a London Suburban Metro, which would bring the line back under the jurisdiction of TfL.[8]


The Great Northern & City Railway (GN&CR) was planned to allow electrified trains to run from the Great Northern Railway (GNR, now the East Coast Main Line) at Finsbury Park to the City of London at Moorgate. Despite being built using similar methods to the tube network then under construction, the tunnels were built large enough to take a main-line train, with an internal diameter of 16 feet (4.9 m), compared with those of the Central London Railway with a diameter less than 12 feet (3.7 m). For this reason the line was popularly known as the "Big Tube" in its early days.[9] However, the GNR eventually opposed the scheme and cancelled its electrification plans, and the line opened in 1904 with the northern terminus in tunnels underneath Finsbury Park GNR station. It was originally electrified using an unusual fourth-rail system with a conductor rail outside both running rails.[10]

The GN&CR was bought in 1913 by the Metropolitan Railway (MR), which operated what are today the Metropolitan and Hammersmith & City lines and the former East London line. The MR had plans to link it to the Circle and Waterloo & City lines, but these were never fulfilled.[10] During this period, the line remained an isolated branch, without through services to any other part of the rail network. Carriages were brought to it through a connection into a freight yard near Drayton Park station, where a small depot was built to service trains.

The GN&CR generating station closed when the MR took over, and became the studio of Gainsborough Pictures. After lying derelict for many years, it became a temporary venue for the Almeida Theatre. It has since been redeveloped as apartments.

After the formation of the London Passenger Transport Board in 1933, the MR was amalgamated with the other Underground railways and the line was renamed the Northern City Line. In 1934 it was re-branded as part of the Edgware–Morden line (which was renamed the Northern line in 1937), and in 1939 operations were transferred from the Metropolitan to the Northern. As part of London Transport's New Works Programme, the Northern Heights plan was to connect the Northern City Line at Finsbury Park to existing main-line suburban branches running to Alexandra Palace, High Barnet and Edgware, which would be taken over by London Transport and electrified. The Highgate branch of the Edgware–Morden line would connect to this network north of Highgate. Only parts of this plan were completed: when the Second World War started, the Highgate link and electrification of the Barnet branch were well under way and ultimately completed, but the Northern City connection to Highgate was first postponed and finally cancelled after the war.

After the war there were proposals to extend the Northern City Line north and south. The London Plan Working Party Report of 1949 proposed several new lines and suburban electrification schemes for London, lettered from A to M. The lower-priority routes J and K would have seen the Northern City Line extended to Woolwich (Route J) and Crystal Palace (Route K), retaining the "Northern Heights" extensions to Edgware and Alexandra Palace. The lines would have run in small-diameter tube tunnels south from Moorgate to Bank and London Bridge.[11] The "K" branch would have run under Peckham to Peckham Rye, joining the old Crystal Palace (High Level) branch (which was still open in 1949) near Lordship Lane. Nothing came of these proposals, and the Edgware, Alexandra Palace and Crystal Palace (High Level) branches were all closed to passengers in 1954. As a result, the Northern City Line remained isolated from the rest of the network.

Services were cut back from Finsbury Park to Drayton Park in 1964, to make room for the Victoria line to use the low-level platforms at Finsbury Park. The former Piccadilly line platforms became the northbound Piccadilly and Victoria lines' platforms, and the former Northern City Line platforms the southbound equivalents. At the same time a change was made at Highbury & Islington, with the northbound Northern City line diverted to a new platform alongside the northbound Victoria line, and the southbound Victoria using the former northbound Northern City platform, both providing cross-platform interchange. Passengers from Moorgate to Finsbury Park took the Northern City line to Highbury & Islington and then changed onto the Victoria.

In 1970 the line was renamed Northern line (Highbury Branch) and the following year an agreement was made to transfer it to British Rail and connect it (as intended by its original promoters) to the mainline via surface platforms at Finsbury Park as part of a wider plan to electrify ECML suburban services. By running commuter trains to Moorgate instead of King's Cross, congestion at King's Cross was relieved.

The last London Underground services ran in October 1975 and British Rail services commenced in August 1976, replacing services to Broad Street via the city branch of the North London Line. These British Rail services used the name "Great Northern Electrics". The track and tunnels are now owned by Network Rail. Services are provided by Great Northern to Welwyn Garden City and, via the Hertford Loop Line, to Hertford North (with some extending to Stevenage, Hitchin or Letchworth). The name "Northern City Line" has been revived to refer to the underground part of the route.


From Finsbury Park to Drayton Park traction current is supplied at 25 kV AC via overhead line, controlled by York Electrical Control Room.[12]

From Drayton Park to Moorgate traction current is supplied at 750 V DC via third rail. There are two electrical sections,[12] separated by a gap at Poole Street:

  • Queensland Road to Poole Street
  • Poole Street to Finsbury Circus

Trains change from AC to DC traction supply, or vice versa whilst standing at Drayton Park station.[12] The platform starter signal on the Up platform at Drayton Park is held at danger (red) as the train approaches. This ensures that all trains stop and drop the pantograph before entering the tunnel.

Signalling is controlled from Kings Cross power box.[12] Between Drayton Park and Moorgate there is no Automatic warning system or Train Protection & Warning System equipment provided, due to the position of the auxiliary return rail[12]. All signals are multiple aspect colour light signals fitted with train stop arms.[12]

Operating procedures

Because mainline trains operate over the infrastructure inherited from London Underground, there are some practices on the NCL which differ from Railway Rulebook instructions, and these are contained in an additional publication.[12] These include:

Passing signals at danger

If a train is standing at a signal at danger inside a tunnel and the driver is unable to contact the signaller, the driver is permitted to pass that signal under their own authority. As soon as the train starts to move, the tripcock on the train will operate and stop the train so the driver must reset that before continuing. They must then proceed with caution, be prepared to stop short of any obstruction, and travel no faster than 3 mph (4.8 km/h).[12] When they reach the next signal they must stop and attempt to contact the signaller, to inform the signaller of what has taken place regardless of the aspect that it is showing.

Platform starter signals (which let the train into a tunnel) can only be passed at danger with the signaller's authority.[12]

Assisting a failed train

Unlike surface lines, the driver of a train which fails on the NCL is not required to leave the train to lay detonators and then wait for the assisting train. The driver remains with the train and the signaller will authorise the driver of the assisting train to proceed to the rear of the failed train at a maximum speed of 3 mph (4.8 km/h).[12] To ensure that the rear of the failed train is always visible, all trains working over the NCL are required to display three red lights at their rear: two tail lamps plus the red portion of the destination roller blind.[12]

On reaching the failed train, the assisting driver will stop short then clip their tunnel telephone onto the tunnel wires so that they can discuss with the driver of the failed train how to carry out the assistance in order to get the trains moving again. Then the two trains are coupled together and the drivers can talk to each other over the usual cab-to-cab handsets before proceeding.

Rolling stock

As part of its contract to supply electrical equipment during the construction of the line, in 1901 British Thomson-Houston provided 35 sets of traction control equipment to Brush Electrical Engineering Company and Dick, Kerr & Company. The original plan was for 11 seven-car trains (33 motors and 44 trailers) and one shunting locomotive. Initially 26 motorcars and 32 trailer cars were built. They were known as the 'wooden' cars because they were fabricated of teak and mahogany on steel underframes. In 1906 Brush delivered another five motors and 13 trailers. There were of all-steel construction and naturally-enough referred to as 'steel cars'. The GN&CR converted one trailer to a motor car, bringing the fleet to 32 motors and 44 trailers. (The remaining sets of traction control equipment were used as maintenance spares.) Normal operation was six-car formations at peak times, reduced to two-car sets at other times. Cars were 56 ft 6 in (17.22 m) long over buffers, 9 ft 4 in (2.84 m) wide, and 12 ft 2 in (3.71 m) in height. Seats were provided for 58 passengers in the wooden trailers and 64 in the steel ones. Motor cars seated 54 because of a 2 ft 10 in (86 cm) equipment compartment behind the driver's cab. Uniquely in England, coupling between cars was by means of link and pin on the centre-line.[13]

The original fleet of 76 carriages was withdrawn and replaced by London Underground Standard Stock on 15 May, 1939.[13] These became the last pre-1938 trains running on the Underground, being phased out during the last weeks of October 1966 through 3 November. 1938 tube stock serviced the line, in variously three-, four- and six-car formations, until its temporary closure on 4 October 1975.[14]

Services are currently operated by dual-voltage Class 313 electric multiple units (EMUs), but are being replaced by Class 717 units as part of a franchise commitment since Govia Thameslink Railway took over management of the line and its services.[15] The Class 717s began to enter service in March 2019.[16]. To comply with the regulations for trains operating in single-bore tunnels where there is not enough clearance space for side evacuation, they have emergency doors at both ends of a unit. When operating on 750 V DC, the two motor coaches of a Class 313 collect traction current from their own shoe gear only; there is no traction bus linking them together as found on most Electric Multiple Units. All Class 313 units operating over the NCL have their Driving Motor B vehicle at the London end, and whilst on 750 V DC are electronically limited to 30 mph (48 km/h),[17] which is the maximum line speed.[4] All stations are long enough to accept six-car trains.[18]

Accidents and incidents

Moorgate tube crash

The Moorgate tube crash, the most serious accident on the London Underground, occurred at Moorgate on 28 February 1975, when a Highbury Branch train ran through the terminus at speed and crashed into the dead end of the tunnel beyond. The cause of the crash, which killed 43 people, was never determined. A report found that there was insufficient evidence to say if it was a deliberate act of the driver or due to a medical condition.

Tunnel penetration incident

On 8 March 2013, pile boring operations from a building site in East Road, Hackney, 13 m (43 ft) above the tunnel, penetrated and obstructed the line between Old Street and Essex Road stations. A serious accident was averted by the actions of an observant train driver, and the line was restricted for several days for repairs. A subsequent investigation by the Rail Accident Investigation Branch was highly critical of the lack of infrastructure protection by Network Rail and carelessness on the part of the site investigation contractor, the piling contractor, and the local planning authority.[19]

Passenger volume

This is the number of passengers using stations on the line from the year beginning April 2002 to the year beginning April 2013.

See also


  1. Network Rail: RUS, ECML Page 57 Accessed 19 Feb 2011
  2. "Great Northern timetable changes from 13 December 2015". Govia Thameslink Railway. Retrieved 13 December 2015.
  3. "East Coast Mainline Routes & Branches part 2". London Reconnections. Retrieved 13 December 2015.
  4. Network Rail (December 2006). London North Eastern Route Sectional Appendix. Module LN2. p. 41. LN105 Seq 001.
  5. Quail Map 2 - England East [page 14] February 1998 (Retrieved 2016-03-10)
  6. Network Rail (December 2009). Kent Sussex & Wessex Sectional Appendix. Module KSW2. p. 136. SO280 Seq 001.
  7. Quail Map 4 - Midlands & North West [page 1R] June 2015 (Retrieved 2016-03-10)
  9. Martin, Andrew (2012). "Chapter 6: Three more tubes". Underground, Overground: A Passenger's History of the Tube. London: Profile. ISBN 9781846684784.
  10. "Northern line". Clive's UndergrounD Line Guides. 3 March 2012. Retrieved 9 March 2012.
  11. J. Glover, "London's Underground", 7th edition, Shepperton, Ian Allan, 1991, p.61.
  12. Work Instructions for D.C. Electrified Lines on the Northern City Line. London, UK: Network Rail. June 2007.
  13. Bruce, J. Graeme (1976). The Big Tube: A short illustrated history of London's Great Northern & City Railway. London: London Transport. p. 27-32. ISBN 0853290717.
  14. Connor, Piers (1989). The 1938 Tube Stock. Harrow Weald, Middlesex, England: Capital Transport. p. 85-86. ISBN 1854141155.
  15. Topham, Gwyn (23 May 2014). "FirstGroup loses Thameslink franchise to Go-Ahead joint venture". The Guardian. London. Retrieved 24 May 2014.
  16. "Great Northern Class 717s finally enter passenger service".
  17. First Capital Connect: Class 313 Conversion Training Guide p.9 General Information "75 mph maximum speed AC Mode– Automatically regulated to 30mph when in DC Mode" 2009.
  18. Network Rail, Rules Of The Plan, 2009, London North Eastern Region
  19. Rail Accident Investigation Branch - Penetration and obstruction of a tunnel between Old Street and Essex Road stations, London. Report name: 0213_R032014_Old_Street


  • Bruce, J. Graeme (1976). The Big Tube: A short illustrated history of London's Great Northern & City Railway. London: London Transport. ISBN 0-85329-071-7.
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