1.
Rapid transit
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Rapid transit, also known as heavy rail, metro, subway, tube, or underground, is a type of high-capacity public transport generally found in urban areas. The stations typically have high platforms, without steps inside the trains and they are typically integrated with other public transport and often operated by the same public transport authorities. However, some transit systems have at-grade intersections between a rapid transit line and a road or between two rapid transit lines. It is unchallenged in its ability to transport large numbers of people quickly over short distances with little use of land, variations of rapid transit include people movers, small-scale light metro, and the commuter rail hybrid S-Bahn. The worlds first rapid-transit system was the partially underground Metropolitan Railway which opened as a railway in 1863. In 1868, New York opened the elevated West Side and Yonkers Patent Railway, china has the largest number of rapid transit systems in the world. The worlds longest single-operator rapid transit system by length is the Shanghai Metro. The worlds largest single rapid transit service provider by both length of revenue track (665 miles and number of stations is the New York City Subway. The busiest rapid transit systems in the world by annual ridership are the Tokyo subway system, the Seoul Metropolitan Subway, the Moscow Metro, the Beijing Subway, Metro is the most common term for underground rapid transit systems used by non-native English speakers. One of these terms may apply to a system, even if a large part of the network runs at ground level. In Scotland, however, the Glasgow Subway underground rapid transit system is known as the Subway, in the US, underground mass transit systems are primarily known as subways, whereas the term metro is a shortened reference to a metropolitan area. In that vein, Chicagos commuter rail system, serving the area, is called Metra. Exceptions in naming rapid transit systems are Washington DCs subway system the Washington Metro, Los Angeles Metro Rail, and the Miami Metrorail, the opening of Londons steam-hauled Metropolitan Railway in 1863 marked the beginning of rapid transit. Initial experiences with steam engines, despite ventilation, were unpleasant, experiments with pneumatic railways failed in their extended adoption by cities. Electric traction was more efficient, faster and cleaner than steam, in 1890 the City & South London Railway was the first electric-traction rapid transit railway, which was also fully underground. Both railways were merged into London Underground. The 1893 Liverpool Overhead Railway was designed to use electric traction from the outset, budapest in Hungary and Glasgow, Chicago and New York all converted or purpose-designed and built electric rail services. Advancements in technology have allowed new automated services, hybrid solutions have also evolved, such as tram-train and premetro, which incorporate some of the features of rapid transit systems
2.
Buenos Aires Underground
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The Buenos Aires Underground, locally known as Subte, is a mass transit metro system that serves the area of the city of Buenos Aires, Argentina. Currently, the underground networks six lines—A, B, C, D, E, the network is complemented by the 7.4 km long Premetro line, and the 26 km long Urquiza suburban line, with 17 more stations in total. As of 2015, the underground also has 4 closed stations, over a million passengers use the network, which also provides connections with the citys extensive commuter rail and bus rapid transport networks. The network expanded rapidly during the decades of the 20th century, by 1944 its main routes were completed. The pace of expansion fell sharply after the Second World War, in the late 1990s expansion resumed at a quicker pace, and four new lines were planned for the network. Despite this, the expansion has been largely exceeded by the transportation needs of the city and is said to be overcrowded. The entire network was nationalised in 1939, remaining in state hands, the Subte opened in 1913, becoming the 13th underground system in the world, as well as the first in Latin America, the Southern Hemisphere and the Hispanophone, followed by the Madrid Metro in 1919. The network was built and operated by three separate private companies and later nationalised in 1939. In 1952 it was absorbed by a state administration, in 1963 it became the property of a newly founded company. All the Underground lines, along with the Urquiza Line and Premetro were offered as 20-year concessions to interested private parties, by 1995, Metrovías took over the Subte under a $395 million plan. In this context, the first proposals for the building of a system were made, along with requests for government grants, first, in 1886. However, the Ministry of Interior denied the city administration the power to license building in the subsoil and for this reason. The first Underground line was opened on 1 December 1913 and was built by the Anglo-Argentine Tramways Company and that line was made up of one of the existing sections of Line A, linking the stations of Plaza de Mayo and Plaza Miserere. 170,000 passengers took part in the lines first trip, on 1 April 1914 the line was to expand to Río de Janeiro station and on 1 July was extended to Primera Junta Station. In 1912 the Lacroze Hermanos company won a concession to build another Underground line, the company was a competitor to the Anglo-Argentine company, operating tramways in Buenos Aires as well as the Buenos Aires Central Railway, which later became part of the Urquiza Line. Construction began in 1927 and this line became Line B when it was inaugurated on 17 October 1930, during 17–18 December 380,000 passengers travelled on the lines then 32 cars. By this point, the AATC had only built 48 metres of what is today Line C, in 1933 a third company, the Hispano-Argentina Company of Public Works and Finances began construction of the other Underground lines. Line Cs first section, Constitución railway station-Diagonal Norte, was inaugurated on 9 November 1934 by Agustín P. Justo, then President of Argentina
3.
Track gauge
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In rail transport, track gauge is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails. All vehicles on a network must have running gear that is compatible with the track gauge, as the dominant parameter determining interoperability, it is still frequently used as a descriptor of a route or network. There is a distinction between the gauge and actual gauge at some locality, due to divergence of track components from the nominal. Railway engineers use a device, like a caliper, to measure the actual gauge, the nominal track gauge is the distance between the inner faces of the rails. In current practice, it is specified at a distance below the rail head as the inner faces of the rail head are not necessarily vertical. In some cases in the earliest days of railways, the company saw itself as an infrastructure provider only. Colloquially the wagons might be referred to as four-foot gauge wagons, say and this nominal value does not equate to the flange spacing, as some freedom is allowed for. An infrastructure manager might specify new or replacement track components at a variation from the nominal gauge for pragmatic reasons. Track is defined in old Imperial units or in universally accepted metric units or SI units, Imperial units were established in United Kingdom by The Weights and Measures Act of 1824. In addition, there are constraints, such as the load-carrying capacity of axles. Narrow gauge railways usually cost less to build because they are lighter in construction, using smaller cars and locomotives, as well as smaller bridges, smaller tunnels. Narrow gauge is often used in mountainous terrain, where the savings in civil engineering work can be substantial. Broader gauge railways are generally expensive to build and require wider curves. There is no single perfect gauge, because different environments and economic considerations come into play, a narrow gauge is superior if ones main considerations are economy and tight curvature. For direct, unimpeded routes with high traffic, a broad gauge may be preferable, the Standard, Russian, and 46 gauges are designed to strike a reasonable balance between these factors. In addition to the general trade-off, another important factor is standardization, once a standard has been chosen, and equipment, infrastructure, and training calibrated to that standard, conversion becomes difficult and expensive. This also makes it easier to adopt an existing standard than to invent a new one and this is true of many technologies, including railroad gauges. The reduced cost, greater efficiency, and greater economic opportunity offered by the use of a common standard explains why a number of gauges predominate worldwide
4.
Railway electrification system
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A railway electrification system supplies electric power to railway trains and trams without an on-board prime mover or local fuel supply. Electrification has many advantages but requires significant capital expenditure, selection of an electrification system is based on economics of energy supply, maintenance, and capital cost compared to the revenue obtained for freight and passenger traffic. Different systems are used for urban and intercity areas, some electric locomotives can switch to different supply voltages to allow flexibility in operation, Electric railways use electric locomotives to haul passengers or freight in separate cars or electric multiple units, passenger cars with their own motors. Electricity is typically generated in large and relatively efficient generating stations, transmitted to the railway network, some electric railways have their own dedicated generating stations and transmission lines but most purchase power from an electric utility. The railway usually provides its own lines, switches and transformers. Power is supplied to moving trains with a continuous conductor running along the track usually takes one of two forms. The first is a line or catenary wire suspended from poles or towers along the track or from structure or tunnel ceilings. Locomotives or multiple units pick up power from the wire with pantographs on their roofs that press a conductive strip against it with a spring or air pressure. Examples are described later in this article, the second is a third rail mounted at track level and contacted by a sliding pickup shoe. Both overhead wire and third-rail systems usually use the rails as the return conductor. In comparison to the alternative, the diesel engine, electric railways offer substantially better energy efficiency, lower emissions. Electric locomotives are usually quieter, more powerful, and more responsive and they have no local emissions, an important advantage in tunnels and urban areas. Different regions may use different supply voltages and frequencies, complicating through service, the limited clearances available under catenaries may preclude efficient double-stack container service. Possible lethal electric current due to risk of contact with high-voltage contact wires, overhead wires are safer than third rails, but they are often considered unsightly. These are independent of the system used, so that. The permissible range of voltages allowed for the voltages is as stated in standards BS EN50163. These take into account the number of trains drawing current and their distance from the substation, railways must operate at variable speeds. Until the mid 1980s this was only practical with the brush-type DC motor, since such conversion was not well developed in the late 19th century and early 20th century, most early electrified railways used DC and many still do, particularly rapid transit and trams
5.
Overhead line
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An overhead line or overhead wire is used to transmit electrical energy to trams, trolleybuses, or trains. Overhead line is designed on the principle of one or more overhead wires situated over rail tracks, the feeder stations are usually fed from a high-voltage electrical grid. Electric trains that collect their current from overhead lines use a device such as a pantograph and it presses against the underside of the lowest overhead wire, the contact wire. Current collectors are electrically conductive and allow current to flow through to the train or tram, non-electric locomotives may pass along these tracks without affecting the overhead line, although there may be difficulties with overhead clearance. Alternative electrical power transmission schemes for trains include third rail, ground-level power supply, batteries and this article does not cover regenerative braking, where the traction motors act as generators to retard movement and return power to the overhead. To achieve good high-speed current collection, it is necessary to keep the wire geometry within defined limits. This is usually achieved by supporting the wire from a second wire known as the messenger wire or catenary. This wire approximates the path of a wire strung between two points, a catenary curve, thus the use of catenary to describe this wire or sometimes the whole system. This wire is attached to the wire at regular intervals by vertical wires known as droppers or drop wires. It is supported regularly at structures, by a pulley, link, the whole system is then subjected to a mechanical tension. As the contact wire makes contact with the pantograph, the insert on top of the pantograph is worn down. The straight wire between supports will cause the wire to cross over the whole surface of the pantograph as the train travels around the curve, causing uniform wear. On straight track, the wire is zigzagged slightly to the left. The movement of the wire across the head of the pantograph is called the sweep. The zigzagging of the line is not required for trolley poles. Depot areas tend to have only a wire and are known as simple equipment or trolley wire. When overhead line systems were first conceived, good current collection was only at low speeds. Compound equipment - uses a second wire, known as the auxiliary
6.
Line E (Buenos Aires Underground)
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Opened in 1944, the Line E was the last completely new line to be added to the Buenos Aires Underground, until 2007 when Line H was opened. The line has a history of being re-routed and extended due to having been historically the line with the lowest passenger numbers on the network. Line E was opened on 20 June 1944, after construction began in 1938, soon after, it was decided to abandon the terminus at Constitución and instead reroute the line towards the Plaza de Mayo. Work began in 1957, and in 1966 the San José, Independencia, Belgrano, for many years, the two stations closed during the re-route remained unused until the mid 1990s when one was converted into a workshop to service the rolling stock of the line. The line was extended in 1973 to José María Moreno. The PreMetro E2 tramway was completed in 1987 and was linked to Line E with the intention of connecting a larger Premetro network to the line, under the private operation of the Subte by Metrovías, the colour of the line was changed from yellow to purple during the 1990s. Purple had previously used for Line C, while yellow is now used for Line H. As of 2014, all major works have been completed on the three new stations and are only missing their tracks and signalling systems. The city will complete the work required in this time. In 2006,64 of the CAF-GEE cars were to be refurbished, there are two ghost stations on the line - San José vieja and Constitución. These formed part of the original trajectory towards Constitución railway station until the line was re-routed in 1966. Both stations have used as workshops and storage areas for the lines rolling stock. San José vieja was used as a set for the 1996 Argentine film Moebius and served as the fictional Dock Sud, Buenos Aires PreMetro Rail transport in Argentina Subterráneos de Buenos Aires Metrovías S. A. Subte Operator Subterráneos de Buenos Aires, E Line System map
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