London Underground

The London Underground is an electric railway public transport network (a metro or subway system) that runs both above and below ground throughout the Greater London area. It is usually referred to by Londoners as either simply "the Underground" , or (more familiarly, due to the shape of its deep-bore tunnels) as "the Tube". It is the oldest and biggest such underground system in the world. Operations began on 10 January 1863 on the Metropolitan Railway; most of the initial route is now part of the Hammersmith & City Line.

Network

(for a map, see below)

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The Underground does not run 24 hours a day because all track maintenance must be done at night after the system closes (unlike other metro systems, such as the New York City Subway, the Underground does not have express tracks that would allow trains to be rerouted around maintenance sites). Recently, greater use has been made of weekend closures of parts of the system to allow scheduled engineering works.

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See also London Underground rolling stock.

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Stations

London Underground currently serves 273 stations, which are listed, along with DLR stations, at List of London Underground stations. Stations formerly served by the Underground or its predecessor companies can be found at List of closed London Underground stations.

Related Topics:
Stations - DLR - List of London Underground stations - List of closed London Underground stations

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The Underground nominally serves 275 stations, but with Heathrow Terminal 4 and Queensway currently closed, presently serves 273. The temporary closure of Heathrow Terminal 4 is for the Heathrow loop to be modified for servicing of Terminal 5, a new two-platform Piccadilly Line terminus. It is planned that services will run in the following pattern:

Related Topics:
Heathrow Terminal 4 - Queensway - Terminal 5

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• Hatton Cross - Heathrow T1,2,3 - Heathrow T5 - Heathrow T1,2,3 Hatton Cross
• Hatton Cross - Heathrow T4 - Heathrow T1,2,3 - Hatton Cross

Some stations have only one platform. These are:

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• Chesham (Metropolitan Line)
• Kensington Olympia (District Line)
• Heathrow Terminal 4 station (Piccadilly Line)
• Mill Hill East (Northern Line)
• Shoreditch (East London Line)

Lines

Lines on the Underground can be classified into two types: sub-surface and deep level. The sub-surface lines were dug by the cut-and-cover method, with the tracks running about 5 m below the surface. Trains on the sub-surface lines have the same loading gauge as British mainline trains. The deep-level or "tube" lines, bored using a tunnelling shield, run about 20 m below the surface (although this varies considerably), with each track running in a separate tunnel lined with cast-iron rings. These tunnels can have a diameter as small as 3.56 m (11 ft 8.25 in) and the loading gauge is thus considerably smaller than on the sub-surface lines, though standard gauge track is used. Lines of both types usually emerge onto the surface outside the central area, the exceptions being the Victoria Line which is in tunnel for its entire length save for a maintenance depot, and the Waterloo & City Line which, being very short, has no non-central part and no surface line. In total, only 45% of the length of the Tube network is in tunnel.

Related Topics:
Cut-and-cover - M - Loading gauge - Tunnelling shield - In - Standard gauge - Victoria Line - Waterloo & City Line

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The lack of lines in the south of the city is sometimes attributed to the geology of that area, the region being almost one large aquifer; additionally, it is impossible for cut and cover lines to go under the River Thames. Rather, the reason seems to be that during the great period of tube-building around the end of the 19th century, South London was already well-served by the electrified and efficiently run suburban lines of the London and South Western Railway and the London, Brighton and South Coast Railway, and so there was no need for tubes. Indeed, to this day, the area is served by a large number of suburban rail services run by the South West Trains, Southern and South East Trains franchise holders, with varying degrees of efficiency (see Rail transport in the United Kingdom). More recently, the Docklands Light Railway (DLR) has been built to serve the east of London, and extends as far south as Lewisham. The Tube interchanges with the DLR at several stations, including Bank, Canary Wharf and Stratford, as well as with the Tramlink system at Wimbledon. Despite these new links, many residents of south and south-east London feel neglected by the Underground proper.

Related Topics:
Geology - Aquifer - Cut and cover - River Thames - 19th century - London and South Western Railway - London, Brighton and South Coast Railway - South West Trains - Southern - South East Trains - Rail transport in the United Kingdom - Docklands Light Railway - Lewisham - Bank - Canary Wharf - Stratford - Tramlink - Wimbledon

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The Tube connects with international Eurostar trains at Waterloo, and runs to Heathrow Airport (Piccadilly Line). Although the latter is slow (52 minutes nominal to Green Park) and often crowded, it is a far cheaper way to travel to the city centre than the Heathrow Express, which is not part of the tube network.

Related Topics:
Eurostar - Waterloo - Heathrow - Green Park - Heathrow Express

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Links to Stansted Airport care of the Stansted Express are at Liverpool Street (on the Central, Circle, Hammersmith & City and Metropolitan Lines) and Tottenham Hale (on the Victoria Line) and to Gatwick care of the Gatwick Express at Victoria, served by the District, Circle and Victoria Lines. A new link to Stansted will be opening later in Summer 2005 from Stratford, served by the Central and Jubilee Lines, as well as the DLR.

Related Topics:
Stansted Airport - Stansted Express - Liverpool Street - Tottenham Hale - Gatwick - Gatwick Express - Victoria - 2005

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The table below describes each of the lines, giving the colour presently used to represent the line on the ubiquitous Tube maps, the date the first section opened and the type of tunnel used.

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The future

Expansion

East London Line

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Preparations are underway to extend the East London Line (ELL) both northwards and southwards while replacing the current 'sub-surface underground' service with one resembling "Metro" surface trains. The northern extension will see the current Shoreditch station closed and the line run on the old Broad Street viaduct to Dalston and then Highbury & Islington, to connect with the Victoria Line. This would bring a non-National Rail service to Hackney for the first time. To the south, two branches are planned, mainly using existing railway lines. The first will run to West Croydon, with a spur to Crystal Palace, while the second would run to Clapham Junction. These changes will by 2010 transform the line from a small stub in the network to a major transport artery.

Related Topics:
East London Line - Shoreditch station - Broad Street - Highbury & Islington - Victoria Line - West Croydon - Crystal Palace - Clapham Junction - 2010

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It is also proposed that together with the existing West London Line and North London Line, the extended ELL could by 2016 form the basis of the long-sought 'Orbital Rail route'.

Related Topics:
West London Line - North London Line - 2016

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Piccadilly Line

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A new station is being built on the Piccadilly Line to serve Terminal 5 of Heathrow Airport. The extension (called PiccEx) consists of a two-platform station, two sidings where trains can be stabled, approximately 3 km of 4.5 m diameter bored tunnels, a ventilation shaft and two escape shafts. Civil works for the two tunnels, the vent shaft, one escape shaft and the structure of T5 station have been completed and track work is now being installed. The junction between PiccEx and the existing Heathrow Loop is now being constructed: this work requires that the tunnels between Terminal 4 and Terminals 1,2,3 be taken out of service until September 2006. The extension is due to be opened in 2007.

Related Topics:
Heathrow Airport - T5 station - Terminal 4 - Terminals 1,2,3 - September - 2006 - 2007

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Metropolitan Line

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TfL, together with Hertfordshire County Council, plans to connect the Watford branch of the Metropolitan Line to the disused Croxley Green Network Rail branch. This will bring the Underground back to central Watford and the important main line station Watford Junction, but the current Watford (Metropolitan) station will probably close.

Related Topics:
Hertfordshire - County Council - Watford - Metropolitan Line - Croxley Green - Watford Junction

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More detailed information on all projects can be found at AlwaysTouchOut.com

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Cooling

In the summer weather, temperatures on the Tube can become very uncomfortable for passengers. Normal air conditioning has been ruled out because of the lack of height to install units on trains and the problems of dispersing the heat generated. Heat pumps were trialled in 1938 and were proposed again several years ago to overcome this, and following a successful demonstration in 2001 funds were given to the School of Engineering at London's South Bank University to develop a prototype; work began in April 2002. A cash reward of £100,000 was offered by the Mayor of London during the hot Summer of 2003 for a solution to the problem but the competition ended in 2005 without a winner being announced.

Related Topics:
Air conditioning - Heat pump - Trialled - 1938 - 2001 - South Bank University - 2002 - £ - Mayor of London - 2003 - 2005

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The new fleet of trains for the sub-surface lines (Circle, District, H&C, Metropolitan and East London lines) will come with air-cooling. The first air-cooled trains are due to arrive in 2009.

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There are posters on the Underground suggesting that passengers carry a bottle of water with them.

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