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Undersea Tunnels
An underwater tunnel is a tunnel which is partly or wholly constructed under the sea or a river. They are often used where building a bridge or operating a ferry link is unviable, or to provide competition or relief for existing bridges or ferry links.Sullivan, WalterProgress In Technology Revives Interest In Great Tunnels New York Times, June 24, 1986. Retrieved 15 August 2010. While short tunnels are often road tunnels which may admit motorized traffic, unmotorized traffic or both, concerns with ventilation lead to the longest tunnels (such as the Channel Tunnel or the Seikan Tunnel) being electrified rail tunnels. Types of tunnel Various methods are used to construct underwater tunnels, including an immersed tube and a submerged floating tunnel. The immersed tube method involves steel tube segments that are positioned in a trench in the sea floor and joined together. The trench is then covered and the water pumped from the tunnel. Submerged floating tunnels use the law of buoya ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel
A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and 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. 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltic Sea Cruiseferries
The Baltic Sea is crossed by several cruiseferry lines. Some important shipping companies are Viking Line, Silja Line, Tallink, St. Peter Line and Eckerö Line. Eastern Baltic Tallink and Viking Line operate competing cruiseferries on the routes Stockholm - Turku and Stockholm - Helsinki, calling in Åland (Mariehamn or Långnäs). Additionally, Tallink sails Stockholm - Mariehamn - Tallinn and Stockholm - Riga. Tallink, Viking Line and Eckerö Line compete on the Helsinki - Tallinn route, which is also the busiest route in the Baltic Sea, travelled by over 6 million people in 2008. , The busiest crossing. The fact that this route is so busy (a further 270,380 people flew between Tallinn Airport and Helsinki Airport in 2018) has led to calls for a Helsinki–Tallinn Tunnel. Baltic routes are mostly served by new ships purpose-built fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blackwall Tunnel
The Blackwall Tunnel is a pair of road tunnels underneath the River Thames in east London, England, linking the London Borough of Tower Hamlets with the Royal Borough of Greenwich, and part of the A102 road. The northern portal lies just south of the East India Dock Road ( A13) in Blackwall; the southern entrances are just south of The O2 on the Greenwich Peninsula. The road is managed by Transport for London (TfL). The tunnel was originally opened as a single bore in 1897 by the Prince of Wales, as a major transport project to improve commerce and trade in London's East End, and supported a mix of foot, cycle, horse-drawn and vehicular traffic. By the 1930s, capacity was becoming inadequate, and consequently a second bore opened in 1967, handling southbound traffic while the earlier 19th century tunnel handles northbound. The northern approach takes traffic from the A12 and the southern approach takes traffic from the A2, making the tunnel crossing a key link for both lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Severn Tunnel
The Severn Tunnel ( cy, Twnnel Hafren) is a railway tunnel in the United Kingdom, linking South Gloucestershire in the west of England to Monmouthshire in south Wales under the estuary of the River Severn. It was constructed by the Great Western Railway (GWR) between 1873 and 1886 for the purpose of dramatically shortening the journey times of their trains, passenger and freight alike, between South Wales and Western England. It has often been regarded as the crowning achievement of GWR's chief engineer Sir John Hawkshaw. Prior to the tunnel's construction, lengthy detours were necessary for all traffic between South Wales and Western England, which either used ship or a lengthy diversion upriver via . Recognising the value of such a tunnel, the GWR sought its development, tasking Hawkshaw with its design and later contracting the civil engineer Thomas A. Walker to undertake its construction, which commenced in March 1873. Work proceeded smoothly until October 1879, at which poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mersey Tunnel
The Mersey Tunnels connect the city of Liverpool with Wirral, under the River Mersey. There are three tunnels: the Mersey Railway Tunnel (opened 1886), and two road tunnels, the Queensway Tunnel (opened 1934) and the Kingsway Tunnel (opened 1971). The railway tunnel and Queensway Tunnel connect central Liverpool with Birkenhead, while the Kingsway Tunnel runs to Wallasey. The road tunnels are owned and operated by Merseytravel, and have their own police force, the Mersey Tunnels Police. In 1967 it was announced that the "Mersey Tunnel Scheme" was now operational. The scheme comprised what was claimed to be the largest closed circuit television system for traffic control outside North America, and featured a bank of 22 CRT monitors. The Queensway Tunnel was used to film scenes for the film ''Harry Potter and the Deathly Hallows – Part 1'' (2010). This provided Claire House children's hospice in Wirral with a £20,000 windfall, the money being paid to Merseytravel by Warne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thames Tunnel
The Thames Tunnel is a tunnel beneath the River Thames in London, connecting Rotherhithe and Wapping. It measures 35 feet (11 m) wide by 20 feet (6 m) high and is 1,300 feet (396 m) long, running at a depth of 75 feet (23 m) below the river surface measured at high tide. It is the first tunnel known to have been constructed successfully underneath a navigable river and was built between 1825 and 1843 by Marc Brunel and his son Isambard using the tunnelling shield newly invented by the elder Brunel and Thomas Cochrane. The tunnel was originally designed for horse-drawn carriages, but was mainly used by pedestrians and became a tourist attraction. In 1869 it was converted into a railway tunnel for use by the East London line which, since 2010, is part of the London Overground railway network under the ownership of Transport for London. History and development Construction At the start of the 19th century, there was a pressing need ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Øresund Bridge
The Öresund or Øresund Bridge ( da, Øresundsbroen ; sv, Öresundsbron ; hybrid name: ) is a combined railway and motorway bridge across the Øresund strait between Denmark and Sweden. It is the longest in Europe with both roadway and railway combined in a single structure, running nearly from the Swedish coast to the artificial island Peberholm in the middle of the strait. The crossing is completed by the Drogden Tunnel from Peberholm to the Danish island of Amager. The bridge connects the road and rail networks of the Scandinavian Peninsula with those of Central and Western Europe. A data cable also makes the bridge the backbone of Internet data transmission between central Europe and Sweden. The international European route E20 crosses via road, the Øresund Line via railway. The construction of the Great Belt Fixed Link (1988–1998), connecting Zealand to Funen and thence to the Jutland Peninsula, and the Øresund Bridge have connected Central and Western Europe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dartford Crossing
The Dartford-Thurrock River Crossing, commonly known as the Dartford Crossing and until 1991 the Dartford Tunnel, is a major road crossing of the River Thames in England, carrying the A282 road between Dartford in Kent in the south and Thurrock in Essex in the north. It consists of two bored tunnels and the cable-stayed Queen Elizabeth II Bridge. The only fixed road crossing of the Thames east of Greater London, it is the busiest estuarial crossing in the United Kingdom, with an average daily use of over 130,000 vehicles. It opened in stages: the west tunnel in 1963, the east tunnel in 1980 and the bridge in 1991. The crossing, although not officially designated a motorway, is considered part of the M25 motorway's route, using the tunnels northbound and bridge southbound. Described as one of the most important road crossings in Britain, it suffers from heavy traffic and congestion. The crossing's development started in the late 1930s, but was interrupted due to the Second W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MS Estonia
MS ''Estonia'' was a cruiseferry built in 1980 at the West German shipyard Meyer Werft in Papenburg. In 1993, she was sold to Nordström & Thulin for use on Estline's Tallinn–Stockholm route. The ship's sinking on 28 September 1994, in the Baltic Sea between Sweden, Finland and Estonia, was one of the worst peacetime maritime disasters of the 20th century, claiming 852 lives. The official report concluded that the bow door had separated from the vessel, pulling the ramp ajar. The ship was already listing because of poor cargo distribution, and the list increased rapidly, flooding the decks and the cabins. Shortly, power failed altogether, inhibiting search and rescue, and a full-scale emergency was not declared for 90 minutes. Of the 989 on board, 138 were rescued. The report criticised primarily the ship's construction, as well as the passive attitude of the crew, failing to notice that water was entering the vehicle deck, delaying the alarm, and providing minimal guidance fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RORO
Roll-on/roll-off (RORO or ro-ro) ships are cargo ships designed to carry wheeled cargo, such as cars, motorcycles, trucks, semi-trailer trucks, buses, Trailer (vehicle), trailers, and railroad cars, that are driven on and off the ship on their own wheels or using a platform vehicle, such as a self-propelled modular transporter. This is in contrast to lift-on/lift-off (LoLo) vessels, which use a crane (machine), crane to load and unload cargo. RORO vessels have either built-in or shore-based Linkspan, ramps or ferry slips that allow the cargo to be efficiently rolled on and off the vessel when in port. While smaller ferries that operate across rivers and other short distances often have built-in ramps, the term RORO is generally reserved for large oceangoing vessels. The ramps and doors may be located in the stern, Bow (ship), bow, or sides, or any combination thereof. Description Types of RORO vessels include ferry, ferries, cruiseferry, cruiseferries, cargo ships, barges, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Surface Effect
The free surface effect is a mechanism which can cause a watercraft to become unstable and capsize. It refers to the tendency of liquids — and of unbound aggregates of small solid objects, like seeds, gravel, or crushed ore, whose behavior approximates that of liquids — to move in response to changes in the attitude of a craft's cargo holds, decks, or liquid tanks in reaction to operator-induced motions (or sea states caused by waves and wind acting upon the craft). When referring to the free surface effect, the condition of a tank that is not full is described as a "slack tank", while a full tank is "pressed up". Stability and equilibrium In a normally loaded vessel any rolling from perpendicular is countered by a righting moment generated from the increased volume of water displaced by the hull on the lowered side. This assumes the center of gravity of the vessel is relatively constant. If a moving mass inside the vessel moves in the direction of the roll, this counters t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Talsinki
Talsinki (sometimes also Hellinna or Hellinn) is a colloquial name for geographical region of Helsinki, Finland and Tallinn, Estonia Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, a ..., separated by the Gulf of Finland, commonly used when referring to the proposed Helsinki–Tallinn Tunnel. The official Euroregion name for the region is Helsinki–Tallinn Euregion. See also * Helsinki to Tallinn Tunnel * Estonian–Finnish federation References External links 'Talsinki' – a 21st century metropolis Culture in Helsinki Tourism in Helsinki Transport in Helsinki Geography of Helsinki Culture in Tallinn Geography of Tallinn Twin cities Euroregions {{Finland-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
