Euston tube station is a London Underground station served by the Victoria Line and both branches of the Northern Line (not to be confused with nearby Euston Square tube station). It directly connects with the Euston mainline station above it. The station is in Travelcard Zone 1.
On the Bank branch of the Northern Line, the station is between Camden Town and King's Cross St Pancras. On the Charing Cross branch it is between Mornington Crescent and Warren Street. On the Victoria Line it is between Warren Street and King's Cross St. Pancras.
On 12 May 1907 the City and South London Railway (C&SLR, now the Bank branch of the Northern Line) opened a station at Euston as the terminus of a new extension from its existing station at Angel. Below ground, the station followed the standard C&SLR configuration of a single island platform with tracks on each side in a large tunnel. The station building was located on Eversholt Street to the east of the London and North Western Railway mainline station and was connected to the platforms by lifts and stairs to the west end of the platform.
On 22 June 1907, the Charing Cross, Euston and Hampstead Railway (CCE&HR, now the Charing Cross branch of the Northern Line) opened between Charing Cross, Archway (then called Highgate) and Golders Green.
Original plans for the route were for it to bypass Euston on a straight alignment to Camden Town. However, the wisdom of bypassing a busy railway station and the large number of customers that it would provide was soon questioned, and the route was revised to serve the mainline station. The station building was constructed to the west of the mainline station with the characteristic red glazed terra cotta elevations of the stations Leslie Green designed for the CCE&HR.
Although built and initially operated as two separate stations by the two companies, the C&SLR and the CCE&HR platforms were sufficiently close together that a deep level interchange was constructed between platforms shortly after opening. A passage was built from near the C&SLR lifts to the east end of the CCE&HR platforms. Unusually this led up from the lifts as the C&SLR platforms were lower than those of the CCE&HR.
At the same time, another passageway was created, leading from the connecting passage to a new set of lifts (and emergency stairs) which surfaced within the mainline station itself. Though the companies continued to maintain their own separate entrances and lifts, it soon became clear that maintaining three entrances so close to each other was unnecessary. The station buildings were closed leaving the entrance within the mainline station to serve both routes. The original exits continued to exist for ventilation reasons; however, the elaborate Moroccan design of the C&SLR building was demolished for a building project.
In 1913 the two lines came under joint ownership when the Underground Group, already owners of the CCE&HR, took over the C&SLR. Plans were made before World War I to extend both lines and provide additional connections at Camden Town and Kennington so that trains could run from either of the two northern termini via either branch to the southern terminus.
Works to modernise and enlarge the C&SLR tunnels which had been originally constructed to a smaller diameter than the CCE&HR closed the line between Moorgate and Euston from 8 August 1922 to 20 April 1924. The new link to Camden Town was opened with the rebuilt C&SLR tunnels. The extensions to Edgware in 1923/24 and to Morden in 1926 lead to the combined line adopting the name Morden-Edgware Line. This changed to the Northern Line in 1937.
To the east of Euston is a connecting tunnel from the northbound Bank branch (fomerly known as the City branch, after the City & South London Railway) to the northbound Piccadilly Line tunnel just south of King's Cross St. Pancras. Via this connection, called the "King's Cross Loop", a train in the northbound Piccadilly Line platform at King's Cross St. Pancras can run south and enter the northbound Bank branch platform at Euston. Alternatively, via a junction, called the "Euston Loop", between the old section of the northbound Bank branch and the southbound Bank branch, trains can enter the southbound platform.
This exchange between lines can be operated in both directions and was created when the C&SLR became part of the Underground group in 1913 to facilitate train stock transfers. At that time the C&SLR had no surface depot and train carriages were lowered into the subterranean depot at Stockwell by a large lift. Originally the junctions concerned were controlled from a signal cabin sited over the headwall of platform 6 (southbound Northern line on the Bank branch); this cabin still exists, but is now operated remotely as an interlocking machine room from the Northern Line control centre at Cobourg Street though facilities remain for manual control of the signals. Presently the junctions are used during train reversals and to facilitate the passage of engineering trains between the Northern and Piccadilly lines.
Use of the Kings Cross and Euston Loops is considered a movement into and out of sidings according to the London Underground Working Reference Manual, and as such is done without passengers on board. However, until relatively recently, trains terminating northbound at Euston did carry passengers from Kings Cross to Euston via the loop line. Now, any such trains detrain passengers at Kings Cross, and then proceed empty to Euston. This may also have been done to prevent passenger confusion, as the northbound terminating train would arrive in the southbound platform at Euston, having passed through the loop. The northbound and southbound platforms on the city branch are not adjacent at Euston, and so any passenger wishing to continue northbound would have to endure a lengthy walk to reach the northbound platform. When there is a scheduled service suspension north of Euston, trains do still proceed to Euston via the loop with passengers, since this is still a passenger signalled move. Once at Euston, they can change to other services.
A new ticket hall was constructed below the concourse of the mainline station with two sets of escalators replacing the lifts. The escalators provide access to and from an intermediate circulation level which, in turn, gives access to the Northern Line Charing Cross branch platforms and two further sets of escalators; one set each serving the northbound and southbound Victoria and Northern Line Bank branch platforms. Interchanges between the northbound and southbound Victoria and Northern Bank Line platforms are made via a passageway at the lower level so as to avoid the need to use the escalators. An emergency stair to the intermediate interchange level is located midway along it. On 1 December 1969 the whole new interchange system was opened and the old passages were closed off. Many of the old passages remain in use as ventilation shafts.
The station is currently in the process of being refurbished by tubelines, the work will be completed in March 2008.
Unlike its neighbour, King's Cross St. Pancras, and most of the other London mainline termini, Euston is not served by the Circle Line. Euston Square tube station is just 250 m away and is served by the Circle, Hammersmith & City and Metropolitan Lines. Some plans see a direct connection being made as part of a new transport interchange project (though alternative plans have Euston Square connecting to Warren Street, which is also nearby).
There are also plans to rebuild the interchange level as part of a mobility impairment accessibility project, possibly restoring use of some of the disused lower level interchange passageways.
The planned segregation of Northern Line services into two separate lines could help reduce confusion between the two Northern Line platforms by renaming one (or both) of the lines (e.g. giving a "Northern Line" and a "City & Southern Line").