London Underground

London Underground
A Central line train at Lancaster Gate
Background
Locale	Greater London, Chiltern, Epping Forest, Three Rivers and Watford
Transit type	Rapid transit
Number of lines	11
Number of stations	270 served (260 owned)
Daily ridership	3.23 million (approximate) 3.66 million (weekdays) (approximate)
Website	www.tfl.gov.uk/tube
Operation
Began operation	10 January 1863
Operator(s)	London Underground Ltd; part of Transport for London (TfL)
Technical
System length	402 kilometres (250 mi)
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge
Electrification	630 V DC Fourth rail
System map

The London Underground (otherwise known as the Underground or the Tube) is a metro system in the United Kingdom, serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex. The system serves 270 stations and has 402 kilometres (250 mi) of track, 45 per cent of which is underground. Since 2003 LUL has been a wholly owned subsidiary of Transport for London (TfL), the statutory corporation responsible for most aspects of the transport system in Greater London, which is run by a board and a commissioner appointed by the Mayor of London.

It incorporates the first underground railway in the world, which opened in 1863 and now forms part of the Circle, Hammersmith & City, and Metropolitan lines and the first line to operate underground electric trains, in 1890, now part of the Northern line. The first tunnels were built just below the surface; later circular tunnels (tubes) were dug through the London Clay. When the Central London Railway opened in 1900, it was known as the "twopenny tube". The lines were marketed as the UNDERGROUND in the early 20th century on maps and signs outside stations. Originally private companies owned and ran the railways and in 1933 these merged to form the London Passenger Transport Board. Harry Beck's tube map appeared for the first time in 1933. The Victoria line was opened 1968–71 and the Jubilee line in 1979, and this was extended in 1999. The Travelcard was introduced in the mid 1980s and the Oyster card in 2003.

Today in official publicity, the term 'tube' embraces the whole underground system, and the tube map now includes the other TfL railways such as the Docklands Light Railway and London Overground as well as the Emirates Air Line. It is the fourth largest metro system in the world in terms of route miles, after the Seoul Metropolitan Subway, Shanghai Metro and the Beijing Subway. It also has one of the largest numbers of stations. In 2011/12 there were 1.2 billion passengers making it the third busiest metro system in Europe, after Moscow and Paris. As of 2011, 86 per cent of operational expenditure on the London Underground is covered by passenger fares. The oldest sections of the London Underground completed 150 years of operations on 10 January 2013. The system is currently being upgraded to increase capacity.

History

Origins

The idea of an underground railway linking the City of London with the railway termini in its urban centre was proposed in the 1830s, and the Metropolitan Railway was granted permission to build such a line in 1854. The world's first underground railway, it opened in January 1863 between Paddington and Farringdon using gas-lit wooden carriages hauled by steam locomotives. It was hailed as a success, carrying 38,000 passengers on the opening day, borrowing trains from other railways to supplement the service. The Metropolitan District Railway (commonly known as the District Railway) opened in December 1868 from South Kensington to Westminster as part of a plan for an underground 'inner circle' connecting London's main-line termini. The Metropolitan and District railways completed the Circle line in 1884, built using the cut and cover method where below the surface. Both railways expanded, the District building five branches to the west reaching Ealing, Hounslow, Uxbridge, Richmond and Wimbledon and the Metropolitan eventually extended as far as Verney Junction in Buckinghamshire, more than 50 miles (80 km) from Baker Street and the centre of London. For the first deep-level tube line, the City and South London Railway, two 10 feet 2 inches (3.10 m) diameter circular tunnels were dug between King William Street (close to today's Monument station) and Stockwell, under the roads to avoid the need for agreement with owners of property on the surface. This opened in 1890 with electric locomotives that hauled carriages with small opaque windows, nicknamed padded cells. The Waterloo and City Railway opened in 1898, followed by the Central London Railway in 1900, known as the "twopenny tube". These two ran electric trains in circular tunnels having diameters between 11 feet 8 inches (3.56 m) and 12 feet 2 inches (3.71 m), whereas the Great Northern and City Railway, which opened in 1904, was built to take main line trains from Finsbury Park to a Moorgate terminus in the City and had 16 feet (4.9 m) diameter tunnels.

In the early 20th century the District and Metropolitan railways needed to electrify and cooperation between the two companies would be needed because of the shared ownership of the inner circle and a joint committee recommended the used of an AC system. The District, needing to raise the finance necessary, found an investor in the American Charles Yerkes. However, he favoured a DC system similar to that in use on the City & South London Railway and Central London Railway. The Metropolitan Railway protested about the change of plan, but after arbitration by the Board of Trade the DC system was adopted. Yerkes soon had control of the District Railway and established the Underground Electric Railways Company of London (UERL) in 1902 to complete and operate three tube lines, the Baker Street and Waterloo Railway (Bakerloo), the Charing Cross, Euston and Hampstead Railway (Hampstead) and the Great Northern, Piccadilly and Brompton Railway, (Piccadilly), which all opened between 1906 and 1907. When the 'Bakerloo' was so named in July 1906, it was called an undignified "gutter title" by The Railway Magazine. By 1907 the District and Metropolitan Railways had electrified the underground sections of their lines. A joint marketing agreement between most of the companies in the early years of the 20th century included maps, joint publicity, through ticketing and UNDERGROUND signs outside stations in Central London. The Bakerloo line was extended north to Queen's Park to join a new electric line from Euston to Watford, but the start of World War I in 1914 delayed construction and trains reached Watford Junction in 1917. An extension of the Central line east to Ealing was also delayed by the war and completed in 1920. People used the tube stations as shelters during air raids in 1915. After the war, government-backed financial guarantees were used to expand the network and the tunnels of the City and South London and Charing Cross, Euston and Hampstead Railways were linked at Euston and Kennington, although the combined service was not named the Northern line until later. The Metropolitan promoted housing estates near the railway with the " Metro-land" brand and nine housing estates were built near stations on the line and electrification was extended north from Harrow to Rickmansworth and a short branch opened from Rickmansworth to Watford in 1925, and from Wembley Park to Stanmore in 1932. The Piccadilly line was extended north to Cockfosters and took over District line branches to Harrow (later Uxbridge) and Hounslow.

London Transport

In 1933, London's underground railways, tramway and bus operators were merged to form the London Passenger Transport Board, this becoming known as London Transport. In the same year Harry Beck's diagrammatic tube map appeared for the first time. Some of the outlying lines of the former Metropolitan Railway closed, such as the Brill Tramway in 1935, and the line from Quainton Road to Verney Junction in 1936. The New Works Programme announced in 1935 included the extension of the Central and Northern lines, and the Bakerloo line to take over the Metropolitan's Stanmore branch. The outbreak of World War II in 1939 suspended some of these plans, although by 1941 the Bakerloo line had reached to Stanmore and the Northern line High Barnet and Mill Hill East. During the war many tube stations were used as air-raid shelters. Following bombing in 1940 passenger services over the West London Line were suspended, leaving Olympia exhibition centre without a railway service until a District line shuttle from Earl's Court began after the war. Work restarted on the Central line extensions in east and west London, and these were complete by 1949. After Britain's railways were nationalised in 1948 the reconstruction of the main line railways was given priority over the maintenance of the Underground and most of the unfinished plans of the pre-war New Works Programme were shelved or postponed.

However, the District line need new trains and an unpainted aluminium train entered service in 1953, this becoming the standard for new trains. In the early 1960s the Metropolitan line was electrified as far as Amersham, British Rail providing services for the former Metropolitan line stations between Amersham and Aylesbury. The Victoria line was a new tube line dug under central London in 1960s and, unlike the earlier tubes, the tunnels did not follow the roads above. The line opened in 1968–71 with the trains being driven automatically and magnetically encoded tickets collected by automatic gates gave access to the platforms. In 1976 the isolated Northern City Line was taken over by British Rail and linked up with the main line railway at Finsbury Park.

In 1979 another new tube, the Jubilee line, named in honour of Queen Elizabeth's Silver Jubilee, took over the Stanmore branch from the Bakerloo line and was extended through the Docklands in 1999. Under the control of the Greater London Council, London Transport introduced a system of fare zones for buses and underground trains that cut the average fare in 1981. Fares increased following a legal challenge but the fare zones were retained, and in the mid 1980s the Travelcard and the Capitialcard were introduced. After the King's Cross fire in November 1987 and to combat graffiti a train refurbishment project was launched in July 1991. In 1984 control of London Buses and the London Underground passed to London Regional Transport (LRT), which reported directly to Secretary of State for Transport. One person operation had been planned in 1968, but conflict with the trade unions delayed introduction until the 1980s.

In the early years of the 21st century London Underground was reorganised in a Public-Private Partnership where private infrastructure companies (infracos) upgraded and maintained the railway. In 2003 control passed to Transport for London (TfL) that had been opposed to the arrangement. One infraco went into administration in 2007 and TfL took over the responsibilities, TfL taking over the other in 2010. Electronic ticketing in the form of the contact-less Oyster card was introduced in 2003. The East London line closed in 2007 so that it could be converted into a London Overground line, and in December 2009 the Circle line changed from serving a closed loop around the centre of London to a spiral also serving Hammersmith.

Transport for London

Transport for London (TfL) was created in 2000 as the integrated body responsible for London's transport system. It replaced London Regional Transport. It assumed control of London Underground Limited in July 2003. TfL is part of the Greater London Authority and is constituted as a statutory corporation regulated under local government finance rules. It has three subsidiaries: London Transport Insurance (Guernsey) Ltd., the TfL Pension Fund Trustee Co. Ltd. and Transport Trading Ltd (TTL). TTL has six wholly owned subsidiaries, one of which is London Underground Limited.

The TfL Board is appointed by the Mayor of London. The Mayor also sets the structure and level of public transport fares in London. However the day-to-day running of the corporation is left to the Commissioner of Transport for London. The current Commissioner is Peter Hendy. The Mayor is responsible for producing an integrated transport strategy for London and for consulting the GLA, TfL, local councils and others on the strategy. The Mayor is also responsible for setting TfL's budget. The GLA is consulted on the Mayor's transport strategy, and inspects and approves the Mayor's budget. It is able to summon the Mayor and senior staff to account for TfL's performance. London TravelWatch, a body appointed by and reporting to the Assembly, deals with complaints about transport in London.

Infrastructure

Railway

The total length of London Underground's eleven lines is 250 miles (402 km) and made up from the sub-surface network and the deep-tube lines. The Circle, District, Hammersmith & City, and Metropolitan lines are services that run on the sub-surface network that has railway tunnels just below the surface and are of a similar size to those on British main lines. The Hammersmith & City and Circle lines share stations and most of the track with other lines. The Bakerloo, Central, Jubilee, Northern, Piccadilly, Victoria and Waterloo & City lines are deep-level tubes, with smaller trains that run in two circular tunnels (tubes) with a diameter of about 11 feet 8 inches (3.56 m) . These lines generally have the exclusive use of a pair of tracks, expect for the Piccadilly line that shares track with the District line between Acton Town and North Ealing and with the Metropolitan line between Rayners Park and Uxbridge, and the Bakerloo line that shares track with London Overground services north of Queen's Park. Fifty-five per cent of the system runs on the surface, and there is 20 miles (32 km) of cut and cover tunnel and 93 miles (150 km) of tube tunnel. Many of the central London underground stations on deep-level tube lines are higher than the running lines to assist deceleration when arriving and acceleration when departing. Trains generally run on the left hand track, although in some places, for example the Central line east of St Paul's station, tunnels are above each other. The running tunnels are on the right on the Victoria line between Warren Street and Euston, allowing a cross-platform interchanges with the Northern line between north bound and south board trains at King's Cross St. Pancras.

The lines are electrified with a four-rail DC system: a conductor rail between the rails is energised at −210 V and a rail outside the running rails at +420 V, giving a potential difference of 630 V. On the sections of line shared with main line trains, such as the District line from East Putney to Wimbledon and Gunnersbury to Richmond, and the Bakerloo line north of Queen's Park, the centre rail is bonded to the running rails.

London Underground lines

Name	Map colour	First operated	First section opened*	Name dates from	T y p e	Length (km)	Length (miles)	No. Sta	Current Stock	Future Stock	Trips per annum (×1000)	Avg. trips per mile (×1000)
Bakerloo line	Brown	1906	1906	1906	DT	23.2.0	14.5.0	25	1972 Stock	n/a	111,136	7,665
Central line	Red	1900	1856	1900	DT	74.00	46.00	49	1992 Stock	n/a	260,916	5,672
Circle line+	Yellow	1884	1863	1949	SS	27.2.0	17.00	36	C Stock	S Stock from 2013	114,609	4,716
District line	Green	1868	1858	1868	SS	64.00	40.00	60	C Stock and D78 Stock	S Stock from 2013	208,317	5,208
Hammersmith & City line+	Pink	1988 (1863 as Metropolitan line)	1858	1988	SS	25.5.0	15.9.0	29	C Stock S Stock	S Stock (Currently being rolled out)	114,609	4,716
Jubilee line	Silver	1979	1879	1979	DT	36.2.0	22.5.0	27	1996 Stock	n/a	213,554	9,491
Metropolitan line	Dark Magenta	1863	1863	1863	SS	66.7.0	41.5.0	34	S Stock	n/a	66,779	1,609
Northern line	Black	1890	1867	1937	DT	58.00	36.00	50	1995 Stock	n/a	252,310	7,009
Piccadilly line	Dark Blue	1906	1869	1906	DT	71.00	44.3.0	53	1973 Stock	n/a	210,169	4,744
Victoria line	Light Blue	1968	1968	1968	DT	21.00	13.250	16	2009 Stock	n/a	199,988	15,093
Waterloo & City line	Turquoise	1898†	1898	1898	DT	2.50.0	1.50.0	2	1992 Stock	n/a	15,892	10,595
* Where a year is shown that is earlier than that shown for First operated, this indicates that the line operates over a route first operated by another Underground line or by another railway company. These dates are sourced from London Railway Atlas, by Joe Brown, Ian Allan Ltd., 2009 (2nd edition). + Passenger figures for both Circle and Hammersmith & City Lines combined. The Avg. trips per mile figure has been calculated using a combined route length of 24.3 miles, sourced from Railway Track Diagrams Vol. 5, by Quail Map Company, 2002 (2nd edition) † Prior to 1994, the Waterloo & City line was operated by British Rail and its predecessors.

The Underground serves 270 stations. Fourteen Underground stations are outside Greater London, of which five ( Amersham, Chalfont & Latimer, Chesham, and Chorleywood on the Metropolitan line, and Epping on the Central line), are beyond the M25 London Orbital motorway. Of the 32 London boroughs, six ( Bexley, Bromley, Croydon, Kingston, Lewisham and Sutton) are not served by the Underground network, while Hackney has Old Street and Manor House only just inside its boundaries.

Trains

London Underground trains come in two sizes, larger sub-surface trains and smaller deep-tube trains. Since the early 1960s all passenger trains have been electric multiple units with sliding doors and a train last ran with a guard in 2000. All lines use fixed length trains with between six and eight cars, except for the Waterloo & City line that uses four cars. New trains are designed for maximum number of standing passengers and for speed of access to the cars and have regenerative braking and public address systems. Since 1999 all new stock has had to comply with accessibility regulations that require such things as access and room for wheelchairs, and the size of location of door controls. All underground trains are required to comply with the The Rail Vehicle Accessibility (Non Interoperable Rail System) Regulations 2010 (RVAR 2010) by 2020.

Stock on sub-surface lines is identified by a letter (such as S Stock, used on the Metropolitan line), while tube stock is identified by the year of intended introduction (for example, 1996 Stock, used on the Jubilee line).

Ventilation and cooling

When the Bakerloo line opened in 1906 it was advertised with a maximum temperature of 16 °C (60 °F), but over time the tube tunnels have warmed up. In 1938 approval was given for a ventilation improvement programme and a refrigerating unit was installed in a lift shaft at Tottenham Court Road. More recently, temperatures of 47 °C (117 °F) were reported in the 2006 European heat wave. It was pointed out in 2002 that, if animals were being transported, temperatures on the Tube would break European Commission animal welfare laws. A 2003 study reported that air quality seventy-three times worse than at street level, with twenty minutes on the Northern line having "the same effect as smoking a cigarette". The main purpose of the London Underground's ventilation fans is to extract hot air from the tunnels and fans over the network are being refurbished, although complaints of noise from local residents preclude their use at full power at night. In June 2006 a groundwater cooling system was installed at Victoria station. In 2012 air cooling units were installed on platforms at Green Park station using cool deep groundwater and at Oxford Circus using chiller units at the top of an adjacent building. New air-conditioned trains are being introduced on the sub-surface lines, but space is limited on tube trains for air-conditioning units and these would heat the tunnels even more. The Deep Tube Programme, investigating replacing the trains for the Bakerloo and Piccadilly lines, is looking for trains with better energy conservation and regenerative braking.

Lifts and escalators

When the deep-tube lines opened, access to the platforms was provided by lifts. Each lift was manned, and at some quiet stations in the 1920s the ticket office was moved into the lift, or it was arranged that the lift could be controlled from the ticket office. The first escalator on the London Underground was at Earl's Court in 1911, between the District and Piccadilly platforms, and the following year all new deep-level stations were provided with escalators instead of lifts. The escalators had a diagonal shunt at the top landing requiring a sideways step off. In 1921 a recorded voice instructed passengers to stand on the right and signs followed in World War II. It is thought that people were standing on the right as it was easier to step off with the right foot at the top of the escalators. The first 'comb' type was installed in 1924 at Clapham Common. In the 1920s and 30s many lifts were replaced by escalators.

There are 426 escalators on the London Underground system and the longest, at 60 metres (200 ft), is at Angel. The shortest, at Stratford, gives a vertical rise of 4.1 metres (13 ft). There are 164 lifts, and numbers have increased in recent years following a programme to increase accessibility.

Wi-Fi and mobile phone reception

In the summer of 2012 London Underground, in partnership with Virgin Media, trialled Wi-Fi hot spots in many stations, but not in the tunnels, that allowed passengers free internet access. The free trial proved successful so it was extended to the end of 2012 whereupon it switched to a service, available to subscribers to Virgin Media and others, or as a paid-for service. It is not currently possible to use mobile phones underground and a project to extend the network before the 2012 Olympics was abandoned due to commercial and technical difficulties.

Planned improvements and expansions

Infrastructure

The signalling system on the Northern line is being replaced to increase capacity on the line by 20 per cent by the end of 2014. Capacity can be increased further if the operation of the Charing Cross and Bank branches are separated. New S Stock trains are being introduced on the sub-surface (District, Metropolitan, Hammersmith & City and Circle) lines, and the track, electrical supply and signalling systems are being upgraded in a programme planned to increase peak-hour capacity by the end of 2018. A single control room for the sub-surface network is to be established in Hammersmith and an automatic train control (ATC) system will replace signalling equipment installed from the 1940s. Options for new trains for the Bakerloo and Piccadilly lines are being considered.

Crossrail is under construction and expected to open in 2018, providing a new underground route across central London integrated with the London Underground system. Options are being considered for the route of Crossrail 2 on a north-south alignment across London, with hopes that it could be open by 2033.

Line extensions

The Croxley Rail Link involves rerouting the Metropolian line's Watford Branch from the current terminus at Watford tube station over the disused Croxley Green branch line to Watford Junction. Funding was agreed in December 2011, and the necessary permission has been requested from the Government. Construction work is expected to start in June 2014 and end by January 2016. It is proposed that the Northern line be extended to Nine Elms and Battersea, and a public enquiry is expected in autumn 2013. It is hoped the stations will open in 2020.

There are suggestions that the Bakerloo Line be extended to Lewisham, and then taking over services on the Hayes Line to relieve capacity on the suburban rail network. The London Borough of Hillingdon has proposed that the Central line be extended from West Ruislip to Uxbridge via Ickenham, claiming the extension would cut traffic on the A40 in the area.

Travelling

Ticketing

The Underground uses Transport for London's zonal fare system to calculate fares. There are nine zones, zone 1 being the central zone, which includes the loop of the Circle line with a few stations to the south of River Thames. The only London Underground stations in Zones 7 to 9 are on the Metropolitan line beyond Moor Park, outside Greater London. Some stations are in two zones, and the cheapest fare applies. Paper tickets or the contactless Oyster card can be used for travel. Single and return tickets are available in either format, but Travelcards (season tickets) for longer than a day are only available on Oyster cards.

TfL introduced the Oyster card in 2003, this is a pre-payment smartcard with an embedded contactless RFID chip. It can be loaded with Travelcards and used on the Underground, the Overground, buses, trams, the Docklands Light Railway, and National Rail services within London. Fares for single journeys are cheaper than paper tickets and a daily cap limits the total cost in a day to the price of a Day Travelcard. The Oyster card must be 'touched' in at the start and the end of a journey, otherwise it is regarded as 'incomplete' and the maximum fare charged. In March 2012 the cost of this in the previous year to travellers was £66.5 million. As of March 2013 contactless payment cards can be used instead of an Oyster card on buses and it is planned to extend this to the Underground in late 2013.

A concessionary fare scheme is operated by London Councils for residents who are disabled or meet certain age criteria. Residents born before 1951 were eligible after their 60th birthday, whereas those born in 1955 will need to wait for they are 66. Called a " Freedom Pass" it allows for free travel on TfL-operated routes at all times and is valid on some National Rail services within London at weekends and after 09:30 on Monday to Fridays. Since 2010, the Freedom Pass has included an embedded holder's photograph; it lasts five years between renewals.

In addition to automatic and staffed ticket gates, the Underground is patrolled by both uniformed and plain-clothes ticket inspectors with hand-held Oyster card readers. Passengers travelling without a valid ticket must pay a penalty fare of £80 (or £40 if paid within 21 days) and can be prosecuted for fare evasion under the Regulation of Railways Act 1889 and Transport for London Byelaws.

Hours of operation

The tube closes overnight, the first trains running from about 05:00 to just after 01:00 the following morning, with later starting times at weekends. The nightly closures are used for maintenance, but some lines stay open at New Year and close later during major public events such as the 2012 London Olympics. London Underground have proposed extending opening times on some lines at the weekend after 2015, following upgrades to the lines. Some lines are closed for scheduled engineering work at weekends to update the system.

The Underground runs limited service on Christmas Eve with some lines closing early, and does not operate on Christmas Day. Since 2010 a dispute between London Underground and trade unions over holiday pay as resulted in a limited service on Boxing Day.

Accessibility

Accessibility by people with mobility problems was not considered when most of the system was built, and most older stations are inaccessible to disabled people. More recent stations were designed for accessibility, but retrofitting accessibility features to old stations is at best prohibitively expensive and technically extremely difficult, and often impossible. Even when there are already escalators or lifts, there are often steps between the lift or escalator landings and the platforms.

Most stations on the surface have at least a short flight of stairs to gain access from street level, and the great majority of below-ground stations require use of stairs or some of the system's 410 escalators. There are also some lengthy walks and further flights of steps required to gain access to platforms. The emergency stairs at Covent Garden station have 193 steps to reach the exit (equivalent to climbing to the top of a 15-floor building), so passengers are advised to use the lifts as climbing the steps can be dangerous.

TfL produces a map that indicates which stations are accessible and, since 2004, line maps indicate with a wheelchair symbol those stations that provide step-free access from street level. Step height from platform to train is up to 300 mm (11.8 in), and there can be a large gap between the train and curved platforms. Only the Jubilee Line Extension is completely accessible.

TfL plans that by 2020 there should be a network of over 100 fully accessible stations, consisting of those recently built or rebuilt, and a handful of suburban stations that happen to have level access, along with selected key stations, which will be rebuilt. These key stations have been chosen due to high usage, interchange potential, and geographic spread, so that up to 75% of journeys will be achievable step-free.

Delays and overcrowding

During peak-hours stations can get so crowded they need to be closed. Passengers may not get on the first train and the majority of passengers do not find a seat on their trains, with some trains having more than four passengers every square metre. When asked, passengers report overcrowding as the aspect of the network that they are least satisfied with, and overcrowding has been linked to poor productivity and potential poor heart health. Capacity increases have been overtaken by increased demand, and peak overcrowding has increased by 16 per cent since 2004/5.

Compared with 2003/4, the reliability of the network had increased in 2010/11, with Lost Customer Hours reduced from 54 million to 40 million. Passengers are entitled to a refund if their journey is delayed by 15 minutes or more due to circumstances within the control of TfL, and in 2010, 330,000 passengers of a potential 11 million Tube passengers claimed compensation for delays. A number of mobile phone apps and services have been developed to help passengers claim their refund more efficiently.

Safety

Accidents on the Underground network, which carries around a billion passengers a year, are rare; there is one fatal accident for every 300 million journeys. Several safety announcements are made, such as the ' mind the gap' announcement and the frequent announcements to passengers to keep behind the yellow line. Relatively few accidents are caused by overcrowding on the platforms: staff monitor platforms and passageways at busy times and prevent people entering overcrowded areas. Access to some stations is restricted at some times to limit overcrowding (e.g., Camden Town is exit-only on Sunday afternoons, with crowds visiting the Camden Markets).

Most fatalities on the network are suicides. Most platforms at deep tube stations have pits, often referred to as 'suicide pits', beneath the track. These were originally constructed to aid drainage of water from the platforms, but they also help prevent death or serious injury when a passenger falls or jumps in front of a train. Suicide pits were first added in 1926 following a surge in numbers of passengers jumping in front of trains.

Design and the arts

TfL's Tube map and " roundel" logo are instantly recognisable by any Londoner, almost any Briton and many people around the world. It has become a major pop culture symbol. TfL licenses the sale of clothing and other accessories featuring its graphic elements and it takes legal action against unauthorised use of its trademarks and of the Tube map. Nevertheless, unauthorised copies of the logo continue to crop up worldwide.

Map

The original maps were often city maps with the lines superimposed, but as well as being visually complex, this produced problems of space, as central stations were far closer together than outlying ones. The modern stylised Tube map evolved from a design by electrical engineer Harry Beck in 1933. It is characterised by a schematic non-geographical layout (thought to have been based on circuit diagrams) and the use of colour-coding for lines. The map is now considered a design classic; virtually every major urban rail system in the world now has a similar map and many bus companies have also adopted the concept. There are many references in culture to the map, including parodies of it using different station-names – an example being the official cover art used on tube maps during 2010. Such references also occur in London advertisements for unrelated products and services.

Typography

Edward Johnston designed TfL's distinctive sans-serif typeface in 1916. The typeface is still in use today although substantially modified in 1979 by Eiichi Kono at Banks & Miles to produce " New Johnston". It is noted for the curl at the bottom of the minuscule (lower case) l, which other sans-serif typefaces have discarded, and for the diamond-shaped tittle on the lower case i and j, whose shape also appears in the full stop, and is the origin of other punctuation marks in the face. TfL owns the copyright to and exercises control over the New Johnston typeface, but a close approximation of the face exists in the TrueType computer font Paddington and the Gill Sans typeface also takes inspiration from Johnston.

Roundel

The origins of the roundel, in earlier years known as the 'bulls-eye' or 'target', are obscure, but the platform signs first appeared in 1907/08 and 1911 or 1912 for the combined logo While the first use of a roundel in a London transport context was the 19th-century symbol of the London General Omnibus Company – a wheel with a bar across the centre bearing the word GENERAL – its use on the Underground stems from the decision in 1908 to find a more obvious way of highlighting station names on platforms. The word "UNDERGROUND" across the bar, as an early corporate identity. One of the chief protagonists of this device was commercial artist Charles Sharland The logo was modified by Edward Johnston in 1919, and again in later years.

The exterior of each station now displays the Underground roundel, for some years this contained the station's name in the central bar at entrances (1948-1959 - some instances remain in situ) and repeatedly along the platform (1908–present), so that the name can easily be seen by passengers on arriving trains. The roundel has been used for buses and the tube for many years and, since TfL took control, it has been applied to other transport types (taxi, tram, DLR etc.) in different colour pairs. The 100th anniversary of the roundel was celebrated by TfL commissioning 100 artists to produce works that celebrate the design. The logo for the 150th Anniversary of the system featured the roundel as the zero.

Contribution to arts

The Underground currently sponsors and contributes to the arts via its Art on the Underground and Poems on the Underground projects. Poster and billboard space (and in the case of Gloucester Road tube station, an entire disused platform) is given over to artwork and poetry to "create an environment for positive impact and to enhance and enrich the journeys of ... passengers".

Its artistic legacy includes the employment, since the 1920s, of many well-known graphic designers, illustrators and artists for its own publicity posters. Designers who produced work for the Underground in the 1920s and 1930s include Man Ray, Edward McKnight Kauffer, William Kermode and Fougasse. In recent years, the Underground has commissioned work from leading artists including R. B. Kitaj, John Bellany and Howard Hodgkin.

In architecture, Leslie Green established a house style for the new stations built in the first decade of the 20th century for the Bakerloo, Piccadilly and Northern lines, which included individual Edwardian tile patterns on platform walls. Tiling was used to help form a corporate image, creating a continuity through the network that encouraged recognition of London Underground property and articulated the orderliness of the network to the general public, and today forms an important part of the look and feel of stations that London Underground is working to conserve. In the 1920s and 1930s, Charles Holden designed a series of modernist and art-deco stations for which the Underground remains famous. Holden's design for the Underground's headquarters building at 55 Broadway included avant-garde sculptures by Jacob Epstein, Eric Gill and Henry Moore (his first public commission). Misha Black was appointed design consultant for the 1960s Victoria Line, contributing to the line's uniform look, while the 1990s extension of the Jubilee line featured stations designed by leading architects such as Norman Foster, Michael Hopkins, Will Alsop and Ian Ritchie. These architects were commissioned by Roland Paoletti, chief architect for the Jubilee Line Extension (JLE).

Many stations also feature unique interior designs to help passenger identification. Often, these have themes of local significance. Tiling at Baker Street incorporates repetitions of Sherlock Holmes's silhouette. Tottenham Court Road features semi-abstract mosaics by Eduardo Paolozzi representing the local music industry at Denmark Street. Northern line platforms at Charing Cross feature murals by David Gentleman of the construction of Charing Cross itself.

In popular culture

The Underground (including several fictitious stations) has been featured in many movies and television shows, including Skyfall, Die Another Day, Sliding Doors, An American Werewolf in London, Creep, Tube Tales and Neverwhere. The London Underground Film Office received over 200 requests to film in 2000. The Underground has also featured in music such as The Jam's " Down in the Tube Station at Midnight" and in literature such as the graphic novel V for Vendetta. Popular legends about the Underground being haunted persist to this day.

The announcement " mind the gap", heard when trains stop at certain platforms, has also become a well known catchphrase.

Call of Duty: Modern Warfare 3 has a level named Mind the Gap where most of the level takes place between the dockyards and Westminster while the player and a team of SAS attempt to take down cargo being shipped using London Underground. The London Underground map serves as a playing field for the conceptual game of Mornington Crescent (which is named after a station on the Northern Line) and the board game The London Game.

On 9 January 2013, Royal Mail issued a set of six postage stamps commemorating the 150th anniversary of the first London underground train journey:

Denomination	Year shown on stamp	Caption	Line colour used as caption background	Image
2nd class	1863	METROPOLITAN RAILWAY OPENS	Metropolitan	A version of the classic lithograph of a steam train at Praed Street Junction near Paddington in the early days of the Metropolitan Railway
2nd class	1898	TUNNELLING BELOW LONDON	Central	Photograph of a Greathead shield being used to excavate a station tunnel on the Central London Railway (in contrast to the cut-and-cover of the Metropolitan Railway)
1st class	1911	COMMUTE FROM THE SUBURBS	District	A version of a poster of the time showing elegant men and women sitting in an uncrowded train
1st class	1934	BOSTON MANOR ART DECO STATION	Piccadilly	The tower of the Grade II listed Boston Manor station building, based on a 1935 photo
£1.28	1938	CLASSIC ROLLING STOCK	Bakerloo	A 1938 tube stock train
£1.28	1999	JUBILEE LINE AT CANARY WHARF	Jubilee	One of the entrance canopies at Canary Wharf, designed by Norman Foster

The commemorative issue includes a "miniature sheet" comprising four further stamps, each featuring three classic London Underground advertising posters from 1908 to 1987.

The Tube

The Tube is the name of two television documentaries about the London Underground. The first was made by ITV in 2002.

In October 2011 the director of BBC Two announced "new" TV series called The Tube, which looks into the life of those who work and travel on London Underground. The show first aired on 20 February 2012. The show follows various London Underground employees in their day-to-day roles.

Notable people

• Frank Pick, Managing Director of the Underground Group from 1928 and Chief Executive of the London Passenger Transport Board from its creation in 1933 until 1940.
• Lord Ashfield, chairman of the Underground Electric Railways Company of London (UERL) from 1910 to 1933 and chairman of the London Passenger Transport Board (LPTB) from 1933 to 1947.
• Edward Watkin, responsible for the building of the Manchester Sheffield & Lincolnshire Railway's " London Extension" during the 1890s, which was the last main line to be constructed into London.
• Edgar Speyer, chairman of the Underground Electric Railways Company of London (UERL, forerunner of the London Underground) from 1906 to 1915, a period during which the company opened three underground railway lines, electrified a fourth and took over two more.
• James Henry Greathead, who helped with the Tower Subway, and became resident engineer on the Hammersmith extension railway and the Richmond extension of the Metropolitan District Railway, a post he held for four years.
• Charles Pearson, who published a pamphlet in 1845 calling for the construction of an underground railway through the Fleet valley to Farringdon. The proposed railway would have been an atmospheric railway with trains pushed through tunnels by compressed air. Although the proposal was ridiculed and came to nothing (and would almost certainly have failed if it had been built, due to the shortcomings of the technology proposed), Pearson continued to lobby for a variety of railway schemes throughout the 1840s and 1850s. In 1846, Pearson proposed with the support of the City Corporation a central railway station for London located in Farringdon that was estimated to cost £1 million (approximately £71.7 million today).
• Daniel Gooch, who designed and built 22 outside-cylinder 2-4-0 locomotives for the line in 1863.
• Charles Yerkes, an American tycoon with experience of operating electric tramways in Chicago. He was also an expert in arranging the complex financial structures necessary to raise the capital the railway companies needed. In 1900, he bought the powers of the CCE&HR company. The following year he secured effective control of the District with a view to its electrification.
• Edward Johnston, who designed the Johnston typeface for the Underground in 1913.
• Harry Beck, a London Underground employee who, in 1931, devised the famous diagrammatic map, which is the template for many rapid transit system maps across the world.