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Abdalajís Tunnel
The Abdalajís Tunnel is a railway tunnel that forms part of the Córdoba-Málaga high-speed rail line as it crosses the Cordillera Penibética mountains. At a length of , it is the fourth-longest operational railway tunnel in Spain. Its completion in 2009 facilitated high speed trains to travel between the cities of Madrid and Málaga in roughly two hours and 20 minutes. Excavation of the Abdalajís Tunnel commenced during November 2003. Progress was initially quick, but suffered several stoppages on account of methane gas, geological instability, and water ingress. The construction was controversial, in part due to its impact on an aquifer and disruption to local water supplies. Work proceeded through to breakthrough in early 2006; three years later, the Abdalajís Tunnel was opened to traffic for the first time. Monitoring of the tunnel's condition and that of the surrounding geology has continued into its operational life, along with routine inspections to ensure its condition. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anhydrite
Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium ( baryte) and strontium ( celestine) sulfates, as might be expected from the chemical formulas. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The Mohs hardness is 3.5, and the specific gravity is 2.9. The color is white, sometimes greyish, bluish, or purple. On the best developed of the three cleavages, the lustre is pearly; on other surfaces it is glassy. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO4·2H2O) by the absorption of water. This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to around under normal atmospheric conditions. Anhydrite is comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tilting Train
A tilting train is a train that has a mechanism enabling increased speed on regular rail tracks. As a train (or other vehicle) rounds a curve at speed, objects inside the train experience centrifugal force. This can cause packages to slide about or seated passengers to feel squashed by the outboard armrest, and standing passengers to lose their balance. Tilting trains are designed to counteract this by tilting the carriages towards the inside of the curve, thus compensating for the g-force. The train may be constructed such that inertial forces cause the tilting (''passive tilt''), or it may have a computer-controlled powered mechanism (''active tilt''). The first passive tilting car design was built in the US in 1937, and an improved version was built in 1939. The beginning of World War II ended development. Talgo introduced a version based on their articulated bogie design in 1950s, and this concept was used on a number of commercial services. Among these was the UAC Turbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AVE Class 102
The Renfe Class 102 or S-102S-102 denotes 'Serie 102 de Renfe', the 1xx series is used for fixed passenger high speed electric trains (nicknamed "Pato" in Spanish, because of its nose that looks like the beak of a duck) is a high-speed train used for the AVE service and operated in Spain by the state-run railway company Renfe, and based on Bombardier Transportation's power car technology. Outside AVE service, Talgo markets this train as the Talgo 350. Further production of closely related trains, differing in seating arrangement, resulted in the S-112. Background, design and orders The AVE Class 102 was constructed by Talgo with Adtranz (later Bombardier Transportation) providing the power car technology. It was principally designed for the Madrid-Barcelona line. The trainsets consist of Talgo passenger cars modified in order to allow speeds of up to with power cars at each end. However, its certified maximum operating speed is due to the limits of its eight motors. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel Boring Machine
A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can be designed to bore through hard rock, wet or dry soil, or sand. Tunnel diameters can range from (micro-TBMs) to to date. Tunnels of less than a metre or so in diameter are typically done using trenchless construction methods or horizontal directional drilling rather than TBMs. TBMs can be designed to excavate non-circular tunnels, including u-shaped, horseshoe, square or rectangular tunnels. Tunnel boring machines are used as an alternative to drilling and blasting (D&B) methods in rock and conventional "hand mining" in soil. TBMs have the advantages of limiting the disturbance to the surrounding ground and producing a smooth tunnel wall. This significantly reduces the cost of lining the tunnel, and makes them suitable to use in urban areas. The major disadvan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dragados
ACS, Actividades de Construcción y Servicios, S.A. () is a Spanish company dedicated to civil and engineering construction, all types services and telecommunications. It is one of the leading construction companies in the world, with projects in many countries around the world. The company was founded in 1997 through the merger of ''OCP Construcciones, S.A.'' and ''Ginés Navarro Construcciones, S.A.'' The group has a presence in Germany, India, Brazil, Chile, Morocco and Australia. The headquarters are in Madrid and the chairman is Florentino Pérez. Listed on the Bolsa de Madrid, the company's shares form part of the IBEX 35 stock market index. History The company was formed when a team of engineers acquired ''Construcciones Padrós S.A.'', a construction business which had been in financial difficulty, in 1983. The company acquired a majority holding in ''Cobra'', a support services business, and merged with ''OCISA S.A.'' to create ''OCP Construcciones, S.A.'' in 1993; it we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karst
Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant rocks, such as quartzite, given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. However, in regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground. The study of ''paleokarst'' (buried karst in the stratigraphic column) is important in petroleum geology because as much as 50% of the world's hydrocarbon reserves are hosted in carbonate rock, and much of this is found in porous karst systems. Etymology The English word ''karst'' was borrowed from German in the late 19th century, which entered German much earlier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay particles, but become hard, brittle and non–plastic upon drying or firing. Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide. Clay is the oldest known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been dated to around 14,000 BC, and clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordillera Penibética
The Penibaetic System ( es, Sistema Penibético or ''Cordillera Penibética'') is the southernmost of the three systems of mountain ranges of the Baetic System in the southern Iberian Peninsula. It includes the highest point in the peninsula, 3,478 m high Mulhacén in the Sierra Nevada. Geography The Penibaetic System runs along the south coast of Andalusia, from the province of Cádiz, across the province of Granada, into the Region of Murcia until reaching the Campo de Cartagena. Along its northern side, across the intermontane basins known as the Hoya de Baza and the Hoya de Guadix, runs the Subbaetic System. The Intrabaetic Basin ( es, Surco Intrabético), a discontinuous series of valleys, separates the Cordillera Penibética from the Cordillera Subbética in the north. Mountain ranges The main mountain ranges that make up the Penibaetic complex are, from west to east, the Serranía de Ronda, the Sierra de Grazalema, the Sierra de Tejeda, Sierra de Almijara, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viaduct
A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide valley, road, river, or other low-lying terrain features and obstacles. The term ''viaduct'' is derived from the Latin ''via'' meaning "road", and ''ducere'' meaning "to lead". It is a 19th-century derivation from an analogy with ancient Roman aqueducts. Like the Roman aqueducts, many early viaducts comprised a series of arches of roughly equal length. Over land The longest in antiquity may have been the Pont Serme which crossed wide marshes in southern France. At its longest point, it measured 2,679 meters with a width of 22 meters. Viaducts are commonly used in many cities that are railroad hubs, such as Chicago, Birmingham, London and Manchester. These viaducts cross the large railroad yards that are needed for freight trains there, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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