A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods.
Euston railway station is a central London railway terminus managed by Network Rail in the London Borough of Camden. It is the southern terminus of the West Coast Main Line, the UK's busiest inter-city railway. Euston is the tenth-busiest station in Britain and the country's busiest inter-city passenger terminal, being the gateway from London to the West Midlands, North West England, North Wales and Scotland.
Crossrail is a railway construction project centred around London. Its aim is to provide a high-frequency hybrid commuter rail and rapid transit system crossing the capital from suburbs on the west to east, by connecting two major railway lines terminating in London: the Great Western Main Line and the Great Eastern Main Line. The project was approved in 2007, and construction began in 2009 on the central section and connections to existing lines that became part of the route, which has been named the Elizabeth line in honour of Queen Elizabeth II who opened the line on 17 May 2022 during her Platinum Jubilee. The central section of the line between Paddington and Abbey Wood opened on 24 May 2022, with 12 trains per hour running in each direction through the core section in Central London.
A tunnelling shield is a protective structure used during the excavation of large, man-made tunnels. When excavating through ground that is soft, liquid, or otherwise unstable, there is a potential health and safety hazard to workers and the project itself from falling materials or a cave-in. A tunnelling shield can be used as a temporary support structure. It is usually in place for the short-term from when the tunnel section is excavated until it can be lined with a permanent support structure. The permanent structure may be made up of, depending on the period, bricks, concrete, cast iron, or steel. Although modern shields are commonly cylindrical, the first "shield", designed by Marc Isambard Brunel, was actually a large, rectangular, scaffold-like iron structure with three levels and twelve sections per level, with a solid load-bearing top surface. The structure protected the men from cave-ins as they laboured within it, digging the tunnel out in front of the shield.
Euston is a London Underground station. It directly connects with Euston main line station above it. The station is in Travelcard Zone 1.
A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels. Tunnels are excavated through hard rock, wet or dry soil, or sand, each of which requires specialized technology.
Old Oak Common (OOC) is a railway station under construction on the site of the Old Oak Common traction maintenance depot to the west of London in Old Oak Common, approximately 500 m (1,600 ft) south of Willesden Junction station. When built, it is expected to be one of the largest rail hubs in London, at about 800 m (2,600 ft) in length and 20 m (66 ft) below surface level.
High Speed 2 (HS2) is a planned high-speed railway line and network of passenger train services in Great Britain. The new railway line, which is currently under construction in England, is to run between the West Midlands and London, with a spur to Birmingham. A network of train services will use the new line and existing conventional track to reach their destinations in the Midlands, North West England, and Scotland. HS2 is to be Britain's second purpose-built high-speed line after High Speed 1, which connects London to the Channel Tunnel. The majority of the project is planned to be completed between 2029 and 2033.
Herrenknecht AG is a German company that manufactures tunnel boring machines, headquartered in Allmannsweier, Schwanau, Baden-Württemberg. It is the worldwide market leader for heavy tunnel boring machines. Roughly two-thirds of its 5,000 employees work at the company's headquarters in the installation of hydraulic and electronic components and final inspection. Approximately 300 work at three locations across China. The company has 82 subsidiaries around the world and has worked on 2,600 projects.
The Bosphorus Water Tunnel or Bosporus aqueduct is an undersea aqueduct in Istanbul, Turkey, crossing the Bosphorus strait. It was constructed in 2012 to transfer water from the Melen Creek in Düzce Province to the European side of Istanbul.
The Lee Tunnel, also known as the Stratford to East Ham deep tunnel, is an overflow sewer in East London for storage and conveyance of foul sewage mixed with rainwater. It was built as part of the Thames Tideway Scheme and runs from Abbey Mills Pumping Station down to pumps and storage tanks at Jenkins Lane, Beckton Sewage Treatment Works. It is wholly under the London Borough of Newham.
A station box is a term in the construction industry: It describes a box-like underground structure for a transportation system, for example a metro or tube station.
The Tuen Mun - Chek Lap Kok TBM is the world's largest tunnel boring machine launched in June 2015 by Herrenknecht in Germany. The TBM is used to drill a 5 km tunnel connecting Tuen Mun to the Hong Kong International Airport, part of the Tuen Mun–Chek Lap Kok Link project. The machine has a diameter of 17.6 metres (57.7 ft), 0.1 metres (0.3 ft) more than Bertha, the previous largest tunnel boring machine.
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 ground water conditions, the length and diameter of the tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and shape of the tunnel and appropriate risk management. Tunnel construction is a subset of underground construction.
Stepney Green cavern is an underground junction which contains the junction where Crossrail divides into two branches: one to Shenfield and one to Abbey Wood. It is located below Stepney Green Park.
The Woodsmith Mine Tunnel is a 23-mile (37 km) long tunnel that will stretch between Woodsmith Mine at Sneatonthorpe near Whitby in North Yorkshire and the Wilton International complex on Teesside, England. The tunnel has been in development since 2016, but cutting of the tunnel bore did not start until April 2019, with a projected finish date of 2021, but it was still not complete by the end of 2023. By the end of July 2020, over 4 miles (6.4 km) of tunnel had been dug.
The Colne Valley Viaduct is a bridge, under construction as of 2023, which will carry the High Speed 2 railway over the Colne Valley Regional Park and the Grand Union Canal, in Hillingdon, west London. When completed, its length of 3.4 kilometres (2.1 mi) and a weight of 116,000 tonnes will make it the largest railway bridge in the UK. It is one of the largest single civil engineering works of HS2 Phase 1.
Euston Square Gardens is a public garden on Euston Road in the London Borough of Camden.
The Chiltern Tunnel is a high-speed railway tunnel currently under construction in Buckinghamshire and Hertfordshire, England, and will upon completion carry the High Speed 2 (HS2) railway line under the Chiltern Hills. The twin-bore tunnels, which are 16.04 km long, will be the longest on the HS2 line. Each tunnel will also have additional 220 m (720 ft) entry and 135 m (443 ft) exit perforated concrete portals to reduce sudden changes in air pressure and subsequent noise.
The Northolt Tunnel is a high-speed railway tunnel currently under construction in Greater London, England, and will upon completion carry the High Speed 2 (HS2) railway line under the West London suburbs. The twin-bore tunnels will run for 8.4 miles (13.5 km) between Old Oak Common and Ruislip. As of January 2024, the first tunnel boring machine has completed 35% of its bore length.
