105-398: Clapham South is a station on London Underground 's Northern line between Clapham Common and Balham . The station is located at the corner of Balham Hill ( A24 ) and Nightingale Lane, at the southern edge of Clapham Common . It is in both Travelcard Zone 2 and Travelcard Zone 3 . The station was designed by Charles Holden and was opened on 13 September 1926 as the first station of
210-594: A day use District Line tracks between Wimbledon and East Putney. 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
315-451: A day. In 2023/24 it was used for 1.181billion passenger journeys. The system's first tunnels were built just below the ground, using the cut-and-cover method; later, smaller, roughly circular tunnels—which gave rise to its nickname, the Tube—were dug through at a deeper level. Despite its name, only 45% of the system is under the ground: much of the network in the outer environs of London
420-783: A diameter of about 11 feet 8 inches (3.56 m), with one tube for each direction. The seven deep-level lines have the exclusive use of tracks and stations along their routes with the exceptions of the Piccadilly line, which shares track with the District line, between Acton Town and Hanger Lane Junction, and with the Metropolitan line, between Rayners Lane and Uxbridge; and the Bakerloo line, which shares track with London Overground 's Watford DC Line for its above-ground section north of Queen's Park. Fifty-five per cent of
525-449: A large factor in the decision making process. Civil engineers usually use project management techniques for developing a major structure. Understanding the amount of time the project requires, and the amount of labor and materials needed is a crucial part of project planning. The project duration must be identified using a work breakdown structure and critical path method . Also, the land needed for excavation and construction staging, and
630-467: A pipe jack, with the span of some box jacks in excess of 20 metres (66 ft). A cutting head is normally used at the front of the box being jacked, and spoil removal is normally by excavator from within the box. Recent developments of the Jacked Arch and Jacked deck have enabled longer and larger structures to be installed to close accuracy. There are also several approaches to underwater tunnels,
735-517: A potential difference of 630 V . On the sections of line shared with mainline 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. The average speed on the Underground is 20.5 mph (33.0 km/h). Outside the tunnels of central London, many lines' trains tend to travel at over 40 mph (64 km/h) in
840-594: A public transport system. The LPTB commissioned many new station buildings, posters and public artworks in a modernist style. The schematic Tube map , designed by Harry Beck in 1931, was voted a national design icon in 2006 and now includes other transport systems besides the Underground, such as the Docklands Light Railway , London Overground , Thameslink , the Elizabeth line , and Tramlink . Other famous London Underground branding includes
945-421: A specialized method called clay-kicking for digging tunnels in clay-based soils. The clay-kicker lies on a plank at a 45-degree angle away from the working face and rather than a mattock with his hands, inserts with his feet a tool with a cup-like rounded end, then turns the tool with his hands to extract a section of soil, which is then placed on the waste extract. Clay-kicking is a specialized method developed in
1050-434: A tube can be sunk into a body of water, which is called an immersed tunnel. Cut-and-cover is a simple method of construction for shallow tunnels where a trench is excavated and roofed over with an overhead support system strong enough to carry the load of what is to be built above the tunnel. There are two basic forms of cut-and-cover tunnelling: Shallow tunnels are often of the cut-and-cover type (if under water, of
1155-747: A tunnel than a sufficiently strong bridge). Some water crossings are a mixture of bridges and tunnels, such as the Denmark to Sweden link and the Chesapeake Bay Bridge-Tunnel in Virginia . There are particular hazards with tunnels, especially from vehicle fires when combustion gases can asphyxiate users, as happened at the Gotthard Road Tunnel in Switzerland in 2001. One of the worst railway disasters ever,
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#17327719272901260-432: A tunnel. Bridges usually require a larger footprint on each shore than tunnels. In areas with expensive real estate, such as Manhattan and urban Hong Kong , this is a strong factor in favor of a tunnel. Boston's Big Dig project replaced elevated roadways with a tunnel system to increase traffic capacity, hide traffic, reclaim land, redecorate, and reunite the city with the waterfront. The 1934 Queensway Tunnel under
1365-452: A wholly owned subsidiary of Transport for London (TfL), the statutory corporation responsible for the transport network in London. As of 2015 , 92% of operational expenditure is covered by passenger fares. The Travelcard ticket was introduced in 1983 and Oyster card , a contactless ticketing system, in 2003. Contactless bank card payments were introduced in 2014, the first such use on
1470-760: 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). The Underground is served by the following depots: In the years since the first parts of the London Underground opened, many stations and routes have been closed. Some stations were closed because of low passenger numbers rendering them uneconomical; some became redundant after lines were re-routed or replacements were constructed; and others are no longer served by
1575-505: Is intended to carry both the Istanbul metro and a two-level highway, over a length of 6.5 km (4.0 miles). The French A86 Duplex Tunnel [ fr ] in west Paris consists of two bored tunnel tubes, the eastern one of which has two levels for light motorized vehicles, over a length of 10 km (6.2 miles). Although each level offers a physical height of 2.54 m (8.3 ft), only traffic up to 2 m (6.6 ft) tall
1680-488: Is on the surface. The early tube lines, originally owned by several private companies, were brought together under the Underground brand in the early 20th century, and eventually merged along with the sub-surface lines and bus services in 1933 to form London Transport under the control of the London Passenger Transport Board (LPTB). The current operator, London Underground Limited (LUL), is
1785-494: Is relatively long and narrow; the length is often much greater than twice the diameter , although similar shorter excavations can be constructed, such as cross passages between tunnels. The definition of what constitutes a tunnel can vary widely from source to source. For example, in the United Kingdom, a road tunnel is defined as "a subsurface highway structure enclosed for a length of 150 metres (490 ft) or more." In
1890-401: Is sometimes necessary during the excavation of a tunnel. They are usually circular and go straight down until they reach the level at which the tunnel is going to be built. A shaft normally has concrete walls and is usually built to be permanent. Once the access shafts are complete, TBMs are lowered to the bottom and excavation can start. Shafts are the main entrance in and out of the tunnel until
1995-515: Is that the open building pit is muted after tunnel construction; no roof is placed. Some tunnels are double-deck, for example, the two major segments of the San Francisco–Oakland Bay Bridge (completed in 1936) are linked by a 160-metre (540 ft) double-deck tunnel section through Yerba Buena Island , the largest-diameter bored tunnel in the world. At construction this was a combination bidirectional rail and truck pathway on
2100-698: Is the Siloam Tunnel , built in Jerusalem by the kings of Judah around the 8th century BC. Another tunnel excavated from both ends, maybe the second known, is the Tunnel of Eupalinos , which is a tunnel aqueduct 1,036 m (3,400 ft) long running through Mount Kastro in Samos , Greece. It was built in the 6th century BC to serve as an aqueduct . In Ethiopia , the Siqurto foot tunnel , hand-hewn in
2205-569: The Balvano train disaster , was caused by a train stalling in the Armi tunnel in Italy in 1944, killing 426 passengers. Designers try to reduce these risks by installing emergency ventilation systems or isolated emergency escape tunnels parallel to the main passage. Government funds are often required for the creation of tunnels. When a tunnel is being planned or constructed, economics and politics play
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#17327719272902310-565: The City & South London Railway in 1890, is now part of the Northern line . The network has expanded to 11 lines with 250 miles (400 km) of track. However, the Underground does not cover most southern parts of Greater London ; there are only 33 Underground stations south of the River Thames . The system's 272 stations collectively accommodate up to 5million passenger journeys
2415-535: 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-foot (4.9 m) diameter tunnels. While steam locomotives were in use on the Underground there were contrasting health reports. There were many instances of passengers collapsing whilst travelling, due to heat and pollution, leading for calls to clean
2520-778: The London 2012 Olympic and Paralympic Games , the Underground saw record passenger numbers, with over 4.3 million people using the Tube on some days. This record was subsequently beaten in later years, with 4.82 million passengers in December 2015. In 2013, the Underground celebrated its 150th anniversary, with celebratory events such as steam trains and installation of a unique Labyrinth artwork at each station. Under TfL, London's public transport network became more unified, with existing suburban rail lines across London upgraded and rebranded as London Overground from 2007, with
2625-598: The London Blitz , a bomb penetrated the booking hall of Bank Station , the blast from which killed 111 people, many of whom were sleeping in passageways and on platforms. On 3 March 1943, a test of the air-raid warning sirens, together with the firing of a new type of anti-aircraft rocket, resulted in a crush of people attempting to take shelter in Bethnal Green Underground station . A total of 173 people, including 62 children, died, making this both
2730-553: The London Passenger Transport Board , which used the London Transport brand . The Waterloo & City Railway , which was by then in the ownership of the main line Southern Railway , remained with its existing owners. In the same year that the London Passenger Transport Board was formed, Harry Beck 's diagrammatic tube map first appeared. In the following years, the outlying lines of
2835-581: The M25 London Orbital motorway ( Amersham , Chalfont & Latimer , Chesham , and Chorleywood on the Metropolitan line and Epping on the Central). Of the thirty-two London boroughs , six ( Bexley , Bromley , Croydon , Kingston , Lewisham and Sutton ) are not served by the Underground network, while Hackney has Old Street (on the Northern line Bank branch) and Manor House (on
2940-468: The Morden extension of the City and South London Railway , which is now part of the Northern line. Other proposed names for the station prior to opening were "Balham North" and "Nightingale Lane" . The apartments above the station, named Westbury Court, were a later addition, built in the mid-1930s. The parade of shops along Balham Hill was extended as part of the same development using the same style as
3045-490: The Northern line from Kennington to Battersea Power Station via Nine Elms . The extension was privately funded, with contributions from developments across the Battersea Power Station , Vauxhall and Nine Elms areas. As of 2021, the Underground serves 272 stations . Sixteen stations (eight on each of the Metropolitan and Central lines) are outside the London region , with five of those beyond
3150-471: The Port Authority of New York and New Jersey was not aware of this bill and had not asked for a grant for such a project. Increased taxes to finance a large project may cause opposition. Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the groundwater conditions, the length and diameter of
3255-848: The Queens-Midtown Tunnel between Manhattan and the borough of Queens on Long Island ; the Detroit-Windsor Tunnel between Michigan and Ontario ; and the Elizabeth River tunnels between Norfolk and Portsmouth, Virginia ; the 1934 River Mersey road Queensway Tunnel ; the Western Scheldt Tunnel , Zeeland, Netherlands; and the North Shore Connector tunnel in Pittsburgh, Pennsylvania . The Sydney Harbour Tunnel
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3360-472: The River Mersey at Liverpool was chosen over a massively high bridge partly for defense reasons; it was feared that aircraft could destroy a bridge in times of war, not merely impairing road traffic but blocking the river to navigation. Maintenance costs of a massive bridge to allow the world's largest ships to navigate under were considered higher than for a tunnel. Similar conclusions were reached for
3465-679: The United Kingdom of digging tunnels in strong clay-based soil structures. This method of cut and cover construction required relatively little disturbance of property during the renewal of the United Kingdom's then ancient sewerage systems. It was also used during the First World War by Royal Engineer tunnelling companies placing mines beneath German lines, because it was almost silent and so not susceptible to listening methods of detection. Tunnel boring machines (TBMs) and associated back-up systems are used to highly automate
3570-529: The Victoria line was dug under central London and, unlike the earlier 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. On 1 January 1970, responsibility for public transport within Greater London passed from central government to local government, in
3675-539: 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. After work restarted on the Central line extensions in east and west London, these were completed in 1949. During the war many tube stations were used as air-raid shelters. They were not always a guarantee of safety however; on 11 January 1941 during
3780-610: The canton of Glarus . The borehole has a diameter of 8.03 metres (26.3 ft). The four TBMs used for excavating the 57-kilometre (35 mi) Gotthard Base Tunnel , in Switzerland , had a diameter of about 9 metres (30 ft). A larger TBM was built to bore the Green Heart Tunnel (Dutch: Tunnel Groene Hart) as part of the HSL-Zuid in the Netherlands, with a diameter of 14.87 metres (48.8 ft). This in turn
3885-625: The roundel and the Johnston typeface , created by Edward Johnston in 1916. The idea of an underground railway linking the City of London with the urban centre was proposed in the 1830s, and the Metropolitan Railway was granted permission to build such a line in 1854. To prepare construction, a short test tunnel was built in 1855 in Kibblesworth , a small town with geological properties similar to London. This test tunnel
3990-489: The water table . This pressurizes the ground ahead of the TBM cutter head to balance the water pressure. The operators work in normal air pressure behind the pressurized compartment, but may occasionally have to enter that compartment to renew or repair the cutters. This requires special precautions, such as local ground treatment or halting the TBM at a position free from water. Despite these difficulties, TBMs are now preferred over
4095-689: The 16th century as a metaphor for a narrow, confined space like the inside of a cask. Some of the earliest tunnels used by humans were paleoburrows excavated by prehistoric mammals. Much of the early technology of tunneling evolved from mining and military engineering . The etymology of the terms "mining" (for mineral extraction or for siege attacks ), " military engineering ", and " civil engineering " reveals these deep historic connections. Predecessors of modern tunnels were adits that transported water for irrigation , drinking, or sewerage . The first qanats are known from before 2000 BC. The earliest tunnel known to have been excavated from both ends
4200-638: The 1960s. The main idea of this method is to use the geological stress of the surrounding rock mass to stabilize the tunnel, by allowing a measured relaxation and stress reassignment into the surrounding rock to prevent full loads becoming imposed on the supports. Based on geotechnical measurements, an optimal cross section is computed. The excavation is protected by a layer of sprayed concrete, commonly referred to as shotcrete . Other support measures can include steel arches, rock bolts, and mesh. Technological developments in sprayed concrete technology have resulted in steel and polypropylene fibers being added to
4305-716: The 1971 Kingsway Tunnel under the Mersey. In Hampton Roads, Virginia , tunnels were chosen over bridges for strategic considerations; in the event of damage, bridges might prevent US Navy vessels from leaving Naval Station Norfolk . Water-crossing tunnels built instead of bridges include the Seikan Tunnel in Japan; the Holland Tunnel and Lincoln Tunnel between New Jersey and Manhattan in New York City ;
Clapham South tube station - Misplaced Pages Continue
4410-473: The Central line east of St Paul's station); or trains run on the right (for example on the Victoria line between Warren Street and King's Cross St. Pancras, to allow cross-platform interchange with the Northern line at Euston ). 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
4515-831: The District Railway and established the Underground Electric Railways Company of London (UERL) in 1902 to finance 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, The Railway Magazine called it an undignified "gutter title". By 1907
4620-696: The District and Metropolitan Railways had electrified the underground sections of their lines. In January 1913, the UERL acquired the Central London Railway and the City & South London Railway , as well as many of London's bus and tram operators. Only the Metropolitan Railway , along with its subsidiaries the Great Northern & City Railway and the East London Railway , and the Waterloo & City Railway , by then owned by
4725-712: The London Underground. In 1976, the Northern City Line was taken over by British Rail and linked up with the main line railway at Finsbury Park , a transfer that had already been planned prior to the accident. In 1979, another new tube, the Jubilee line , named in honour of the Silver Jubilee of Elizabeth II , took over the Stanmore branch from the Bakerloo line, linking it to a newly constructed line between Baker Street and Charing Cross stations. Under
4830-709: The Middle Ages, crosses a mountain ridge. In the Gaza Strip , the network of tunnels was used by Jewish strategists as rock-cut shelters, in first links to Judean resistance against Roman rule in the Bar Kokhba revolt during the 2nd century AD. A major tunnel project must start with a comprehensive investigation of ground conditions by collecting samples from boreholes and by other geophysical techniques. An informed choice can then be made of machinery and methods for excavation and ground support, which will reduce
4935-531: The Piccadilly line) just inside its boundaries. Lewisham was served by the East London line (with stations at New Cross and New Cross Gate ) until 2010 when the line and the stations were transferred to the London Overground network. London Underground's eleven lines total 402 kilometres (250 mi) in length, making it the eleventh longest metro system in the world . These are made up of
5040-455: The Tube has taken place - with new trains (such as London Underground S7 and S8 Stock ), new signalling, upgraded stations (such as King's Cross St Pancras ) and improved accessibility (such as at Green Park ). Small changes to the Tube network occurred in the 2000s, with extensions to Heathrow Terminal 5 , new station at Wood Lane and the Circle line changed from serving a closed loop around
5145-637: The Underground or by its nickname the Tube ) is a rapid transit system serving Greater London and some parts of the adjacent home counties of Buckinghamshire , Essex and Hertfordshire in England. The Underground has its origins in the Metropolitan Railway , opening on 10 January 1863 as the world's first underground passenger railway. The Metropolitan is now part of the Circle , District , Hammersmith & City and Metropolitan lines . The first line to operate underground electric traction trains ,
5250-436: The Underground but remain open to National Rail main line services. In some cases, such as Aldwych and Ongar , the buildings remain and are used for other purposes. In others, such as British Museum , all evidence of the station has been lost through demolition. London Transport Museum runs guided tours of several disused stations including Down Street and Aldwych through its "Hidden London" programme. The tours look at
5355-599: The United States, the NFPA definition of a tunnel is "An underground structure with a design length greater than 23 m (75 ft) and a diameter greater than 1,800 millimetres (5.9 ft)." The word "tunnel" comes from the Middle English tonnelle , meaning "a net", derived from Old French tonnel , a diminutive of tonne ("cask"). The modern meaning, referring to an underground passageway, evolved in
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#17327719272905460-621: The advent of electric Tube services (the Waterloo and City Railway and the Great Northern and City Railway), the Volks Electric Railway , in Brighton , and competition from electric trams, the pioneering Underground companies needed modernising. In the early 20th century, the District and Metropolitan railways needed to electrify and a joint committee recommended an AC system, the two companies co-operating because of
5565-427: The air through the installation of garden plants. The Metropolitan even encouraged beards for staff to act as an air filter. There were other reports claiming beneficial outcomes of using the Underground, including the designation of Great Portland Street as a " sanatorium for [sufferers of ...] asthma and bronchial complaints", tonsillitis could be cured with acid gas and the Twopenny Tube cured anorexia . With
5670-400: The blocky nature of rocks, the exact location of fault zones, or the stand-up times of softer ground. This may be a particular concern in large-diameter tunnels. To give more information, a pilot tunnel (or "drift tunnel") may be driven ahead of the main excavation. This smaller tunnel is less likely to collapse catastrophically should unexpected conditions be met, and it can be incorporated into
5775-432: 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 and location of door controls. All underground trains are required to comply with The Rail Vehicle Accessibility (Non Interoperable Rail System) Regulations 2010 (RVAR 2010) by 2020. Stock on sub-surface lines
5880-553: The centre of London to a spiral also serving Hammersmith in 2009. In July 2005, four coordinated terrorist attacks took place, three of them occurring on the Tube network. It was the UK's deadliest terrorist incident since 1988. Electronic ticketing in the form of the contactless Oyster card was first introduced in 2003, with payment using contactless banks cards introduced in September 2014. In 2019 , over 12million Oyster cards and 35million contactless cards were used, generating around £5billion in ticketing revenue. During
5985-451: The concrete mix to improve lining strength. This creates a natural load-bearing ring, which minimizes the rock's deformation . By special monitoring the NATM method is flexible, even at surprising changes of the geomechanical rock consistency during the tunneling work. The measured rock properties lead to appropriate tools for tunnel strengthening . In pipe jacking , hydraulic jacks are used to push specially made pipes through
6090-399: The control of the GLC, 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 Capitalcard were introduced. In 1984, control of London Buses and the London Underground passed back to central government with
6195-410: The creation of London Regional Transport (LRT), which reported directly to the Secretary of State for Transport , still retaining the London Transport brand. One person operation had been planned in 1968, but conflict with the trade unions delayed introduction until the 1980s. On 18 November 1987, fire broke out in an escalator at King's Cross St Pancras tube station . The resulting fire cost
6300-399: The early 1960s, the Metropolitan line was electrified as far as Amersham , British Railways providing services for the former Metropolitan line stations between Amersham and Aylesbury. In 1962, the British Transport Commission was abolished, and the London Transport Executive was renamed the London Transport Board , reporting directly to the Minister of Transport . Also during the 1960s,
6405-463: The early 2000s, London Underground was reorganised in a Public-Private Partnership (PPP) as part of a project to upgrade and modernise the system. Private infrastructure companies (infracos) would upgrade and maintain the railway, and London Underground would run the train service. One infraco – Metronet – went into administration in 2007, and TfL took over the other – Tube Lines – in 2010. Despite this, substantial investment to upgrade and modernise
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#17327719272906510-618: The emergency services. In April 1994, the Waterloo & City Railway , by then owned by British Rail and known as the Waterloo & City line, was transferred to the London Underground. In 1999, the Jubilee Line Extension project extended the Jubilee line from Green Park station through the growing Docklands to Stratford station . This resulted in the closure of the short section of tunnel between Green Park and Charing Cross stations. The 11 new stations were designed to be " future-proof ", with wide passageways, large quantities of escalators and lifts, and emergency exits. The stations were
6615-409: The entire tunnelling process, reducing tunnelling costs. In certain predominantly urban applications, tunnel boring is viewed as a quick and cost-effective alternative to laying surface rails and roads. Expensive compulsory purchase of buildings and land, with potentially lengthy planning inquiries, is eliminated. Disadvantages of TBMs arise from their usually large size – the difficulty of transporting
6720-441: The final tunnel or used as a backup or emergency escape passage. Alternatively, horizontal boreholes may sometimes be drilled ahead of the advancing tunnel face. Other key geotechnical factors: For water crossings, a tunnel is generally more costly to construct than a bridge. However, both navigational and traffic considerations may limit the use of high bridges or drawbridges intersecting with shipping channels, necessitating
6825-431: The first on the Underground to have platform edge doors , and were built to have step-free access throughout. The stations have subsequently been praised as exemplary pieces of 20th-century architecture. In 2000, Transport for London (TfL) was created as an integrated body responsible for London's transport system. Part of the Greater London Authority , the TfL Board is appointed by the Mayor of London , who also sets
6930-432: The form of the Greater London Council (GLC), and the London Transport Board was abolished. The London Transport brand continued to be used by the GLC. On 28 February 1975, a southbound train on the Northern City Line failed to stop at its Moorgate terminus and crashed into the wall at the end of the tunnel, in the Moorgate tube crash . There were 43 deaths and 74 injuries, the greatest loss of life during peacetime on
7035-479: The former East London line becoming part of the Overground network in 2010. Many Overground stations interchange with Underground ones, and Overground lines were added onto the Tube map. In the 2010s, the £18.8 billion Crossrail project built a new east–west railway tunnel under central London. The project involved rebuilding and expanding several central Underground stations including Tottenham Court Road and Whitechapel . By increasing rail capacity,
7140-504: The former Metropolitan Railway closed, the Brill Tramway in 1935, and the line from Quainton Road to Verney Junction in 1936. The 1935–40 New Works Programme included the extension of the Central and Northern lines and the Bakerloo line to take over the Metropolitan's Stanmore branch. The Second World War suspended these plans after the Bakerloo line had reached Stanmore and the Northern line High Barnet and Mill Hill East in 1941. Following bombing in 1940, passenger services over
7245-405: The ground behind a TBM or shield. This method is commonly used to create tunnels under existing structures, such as roads or railways. Tunnels constructed by pipe jacking are normally small diameter bores with a maximum size of around 3.2 metres (10 ft). Box jacking is similar to pipe jacking, but instead of jacking tubes, a box-shaped tunnel is used. Jacked boxes can be a much larger span than
7350-422: The history of the network and feature historical details drawn from the museum's own archives and collections. Cut-and-cover A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ventilation openings at various points along
7455-587: The immersed-tube type), while deep tunnels are excavated, often using a tunnelling shield . For intermediate levels, both methods are possible. Large cut-and-cover boxes are often used for underground metro stations, such as Canary Wharf tube station in London. This construction form generally has two levels, which allows economical arrangements for ticket hall, station platforms, passenger access and emergency egress, ventilation and smoke control, staff rooms, and equipment rooms. The interior of Canary Wharf station has been likened to an underground cathedral, owing to
7560-435: The inevitable smoke and steam. A major disadvantage of cut-and-cover is the widespread disruption generated at the surface level during construction. This, and the availability of electric traction, brought about London Underground's switch to bored tunnels at a deeper level towards the end of the 19th century. Prior to the replacement of manual excavation by the use of boring machines, Victorian tunnel excavators developed
7665-468: The large TBM to the site of tunnel construction, or (alternatively) the high cost of assembling the TBM on-site, often within the confines of the tunnel being constructed. There are a variety of TBM designs that can operate in a variety of conditions, from hard rock to soft water-bearing ground. Some TBMs, the bentonite slurry and earth-pressure balance types, have pressurized compartments at the front end, allowing them to be used in difficult conditions below
7770-969: The length. A pipeline differs significantly from a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods. A tunnel may be for foot or vehicular road traffic , for rail traffic, or for a canal . The central portions of a rapid transit network are usually in the tunnel. Some tunnels are used as sewers or aqueducts to supply water for consumption or for hydroelectric stations. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons , contraband , or people . Special tunnels, such as wildlife crossings , are built to allow wildlife to cross human-made barriers safely. Tunnels can be connected together in tunnel networks . A tunnel
7875-581: The line aims to reduce overcrowding on the Tube and cut cross-London journey times. The railway opened as the Elizabeth line in May 2022. Although not part of the Underground, the line connects with several Underground stations. In 2020, passenger numbers fell significantly during the COVID-19 pandemic and 40 stations were temporarily closed. The Northern Line Extension opened in September 2021, extending
7980-411: The line. Electrification was extended north from Harrow to Rickmansworth , and branches 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. In 1933, most of London's underground railways, tramway and bus services were merged to form
8085-530: The lives of 31 people and injured a further 100. London Underground was strongly criticised in the aftermath for its attitude to fires underground, and publication of the report into the fire led to the resignation of senior management of both London Underground and London Regional Transport. Following the fire, substantial improvements to safety on the Tube were implemented – including the banning of smoking, removal of wooden escalators, installation of CCTV and fire detectors, as well as comprehensive radio coverage for
8190-629: The lower deck with automobiles above, now converted to one-way road vehicle traffic on each deck. In Turkey, the Eurasia Tunnel under the Bosphorus , opened in 2016, has at its core a 5.4 km (3.4 miles) two-deck road tunnel with two lanes on each deck. Additionally, in 2015 the Turkish government announced that it will build three -level tunnel, also under the Bosporus. The tunnel
8295-633: The main line London and South Western Railway , remained outside the Underground Group's control. A joint marketing agreement between most of the companies in the early years of the 20th century included maps, joint publicity, through ticketing and U NDERGROUN D signs, incorporating the first bullseye symbol, outside stations in Central London. At the time, the term Underground was selected from three other proposed names; 'Tube' and 'Electric' were both officially rejected. Ironically,
8400-483: The older method of tunnelling in compressed air, with an airlock/decompression chamber some way back from the TBM, which required operators to work in high pressure and go through decompression procedures at the end of their shifts, much like deep-sea divers . In February 2010, Aker Wirth delivered a TBM to Switzerland, for the expansion of the Linth–Limmern Power Stations located south of Linthal in
8505-540: The operation of empty and loaded trains at the same time. The temporary way is replaced by the permanent way at completion, thus explaining the term " Perway ". The vehicles or traffic using a tunnel can outgrow it, requiring replacement or enlargement: An open building pit consists of a horizontal and a vertical boundary that keeps groundwater and soil out of the pit. There are several potential alternatives and combinations for (horizontal and vertical) building pit boundaries. The most important difference with cut-and-cover
8610-403: The original three closest to the station. The station was refurbished in the 1990s, with new flooring, tiling and CCTV - albeit ensuring that original Charles Holden features were restored or reproduced. The restoration work was awarded a National Railway Heritage Award. It is one of eight London Underground stations with a deep-level air-raid shelter underneath it. In 1948, the deep shelter
8715-522: The project is completed. If a tunnel is going to be long, multiple shafts at various locations may be bored so that entrance to the tunnel is closer to the unexcavated area. Once construction is complete, construction access shafts are often used as ventilation shafts , and may also be used as emergency exits. The New Austrian Tunnelling method (NATM)—also referred to as the Sequential Excavation Method (SEM) —was developed in
8820-490: The proper machinery must be selected. Large infrastructure projects require millions or even billions of dollars, involving long-term financing, usually through issuance of bonds . The costs and benefits for an infrastructure such as a tunnel must be identified. Political disputes can occur, as in 2005 when the US House of Representatives approved a $ 100 million federal grant to build a tunnel under New York Harbor. However,
8925-482: The risk of encountering unforeseen ground conditions. In planning the route, the horizontal and vertical alignments can be selected to make use of the best ground and water conditions. It is common practice to locate a tunnel deeper than otherwise would be required, in order to excavate through solid rock or other material that is easier to support during construction. Conventional desk and preliminary site studies may yield insufficient information to assess such factors as
9030-508: 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 2.5 inches (3.72 m), whereas
9135-496: 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 stations. The Metropolitan and District railways completed the Circle line in 1884, built using the cut and cover method. Both railways expanded, the District building five branches to
9240-596: The shared ownership of the inner circle. The District, needing to raise the finance necessary, found an investor in the American Charles Yerkes who favoured a DC system similar to that in use on the City & South London and Central London railways. 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
9345-412: The sheer size of the excavation. This contrasts with many traditional stations on London Underground , where bored tunnels were used for stations and passenger access. Nevertheless, the original parts of the London Underground network, the Metropolitan and District Railways, were constructed using cut-and-cover. These lines pre-dated electric traction and the proximity to the surface was useful to ventilate
9450-613: The structure and level of public transport fares in London. The day-to-day running of the corporation is left to the Commissioner of Transport for London . TfL eventually replaced London Regional Transport, and discontinued the use of the London Transport brand in favour of its own brand. The transfer of responsibility was staged, with transfer of control of London Underground delayed until July 2003, when London Underground Limited became an indirect subsidiary of TfL. In
9555-612: The sub-surface network and the deep-tube lines. The Circle , District , Hammersmith & City , and Metropolitan lines form the sub-surface network, with cut-and-cover railway tunnels just below the surface and of a similar size to those on British main lines They converged on a bi-directional loop in central London, sharing tracks and stations with each other at various places along their respective routes. The Bakerloo , Central , Jubilee, Northern, Piccadilly, Victoria and Waterloo & City lines are deep-level tubes, with smaller trains that run in circular tunnels ( tubes ) with
9660-521: The suburban and countryside areas. The Metropolitan line can reach speeds of 62 mph (100 km/h). The London Underground was used for 1.181 billion journeys in the year 2023–2024. The Underground uses several railways and alignments that were built by main-line railway companies. Chiltern Railways shares track with the Metropolitan Line between Harrow-on-the-Hill and Amersham. Three South Western Railway passenger trains
9765-418: The system runs on the surface. There are 20 miles (32 km) of sub-surface tunnels and 93 miles (150 km) of tube tunnels. Many of the central London Underground stations on deep-level tube routes are higher than the running lines to assist deceleration when arriving and acceleration when departing. Trains generally run on the left-hand track. In some places, the tunnels are above each other (for example,
9870-400: The term Tube was later adopted alongside the Underground. The Bakerloo line was extended north to Queen's Park to join a new electric line from Euston to Watford , but the First World War delayed construction and trains reached Watford Junction in 1917. During air raids in 1915 people used the tube stations as shelters. An extension of the Central line west to Ealing was also delayed by
9975-400: The tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and the shape of the tunnel and appropriate risk management. There are three basic types of tunnel construction in common use. Cut-and-cover tunnels are constructed in a shallow trench and then covered over. Bored tunnels are constructed in situ, without removing the ground above. Finally,
10080-428: The two most common being bored tunnels or immersed tubes , examples are Bjørvika Tunnel and Marmaray . Submerged floating tunnels are a novel approach under consideration; however, no such tunnels have been constructed to date. During construction of a tunnel it is often convenient to install a temporary railway, particularly to remove excavated spoil , often narrow gauge so that it can be double track to allow
10185-437: The war and was completed in 1920. After the war, government-backed financial guarantees were used to expand the network and the tunnels of the City and South London and Hampstead railways were linked at Euston and Kennington; 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
10290-562: 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
10395-761: The worst civilian disaster in Britain during the Second World War, and the largest loss of life in a single incident on the London Underground network. On 1 January 1948, under the provisions of the Transport Act 1947 , the London Passenger Transport Board was nationalised and renamed the London Transport Executive , becoming a subsidiary transport organisation of the British Transport Commission , which
10500-575: Was constructed to provide a second harbour crossing and to alleviate traffic congestion on the Sydney Harbour Bridge , without spoiling the iconic view. Other reasons for choosing a tunnel instead of a bridge include avoiding difficulties with tides, weather, and shipping during construction (as in the 51.5-kilometre or 32.0-mile Channel Tunnel ), aesthetic reasons (preserving the above-ground view, landscape, and scenery), and also for weight capacity reasons (it may be more feasible to build
10605-430: Was formed on the same day. Under the same act, the country's main line railways were also nationalised, and their reconstruction 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. The District line needed new trains and an unpainted aluminium train entered service in 1953, this becoming the standard for new trains. In
10710-633: Was quickly filled. As there was no accommodation for all of the new arrivals, the Colonial Office housed many of them temporarily in the deep-level shelter at Clapham South. The underground shelter has been available to visit through London Transport Museum 's Hidden London programme of guided tours since 2016. The station is served by London Buses routes 50 , 155 , 249 , 355 , G1 , 690 , as well as by night route N155 . [REDACTED] London transport portal London Underground The London Underground (also known simply as
10815-732: Was superseded by the Madrid M30 ringroad , Spain, and the Chong Ming tunnels in Shanghai , China. All of these machines were built at least partly by Herrenknecht . As of August 2013 , the world's largest TBM was " Big Bertha ", a 17.5-metre (57.5 ft) diameter machine built by Hitachi Zosen Corporation , which dug the Alaskan Way Viaduct replacement tunnel in Seattle, Washington (US). A temporary access shaft
10920-565: Was used as temporary accommodation for immigrants from the West Indies. The HMT Empire Windrush arrived at Tilbury in 1948 carrying 492 immigrants. London had a severe labour shortage after the war and the Colonial Office had sought to recruit a labour force from Jamaica. An advertisement had appeared in Jamaica's Daily Gleaner on 13 April 1948 offering transport to the UK. The Windrush
11025-458: Was used for two years in the development of the first underground train, and was later, in 1861, filled up. 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, and borrowing trains from other railways to supplement
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