Learn more about Rapid transit
A rapid transit, underground, subway, tube, elevated, or metro(politan) system is a railway — usually in an urban area — with a high capacity and frequency of service, and grade separation from other traffic. The oldest rapid transit system in the world is the London Underground, which opened in 1863. The Tunnel a 573 m long subway opened in 1875 in Istanbul is the second oldest .<ref>Template:Cite journal</ref> The First American system is the Boston Subway.<ref>Template:Cite web</ref> The three primary ways subway tunnels are constructed: cut and cover, tunnel boring, and cover and cut.<ref> "Subway". World Book. ISBN 0716601044.</ref>
More than 200 cities have rapid transit systems. 25 cities have new systems under construction.
- Further information: Passenger rail terminology
A rapid transit is a railbased, transport system used within urban areas to transport people. To be considered a rapid transit, it must meet certain criteria:
- an urban, electric mass transit railway system;
- totally independent from other traffic;
- with high service frequency.
 Elevated verses submerged
Rapid transit can be elevated, on ground or underground. It is quite common for the city core network to be underground, while it varies from system to system what solution is used outside the city core.
The term subway (American English)<ref> The American Heritage Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company. ISBN 0618082301.</ref> and underground (British English)<ref>Template:Cite web</ref> are often used to describe a rapid transit that operates soley or primarily underground. In some cities the word "subway" applies to the entire system, while in others only to those parts that are actually underground, but is commonly called "Metro". Rapid transit systems that are above street level may be called "elevated" systems in the US, often shortened to el (or sometimes L, as in Chicago 'L'). In the UK, elevated systems are generally classified as light railways such as the Docklands Light Railway (DLR) in east London - although not all British light railways are elevated.
 Uses and developments
Rapid transits are generaly used in metropolitain areas to transport large amounts of people at high frequency. The extent of the rapid transit system varies a lot from city to city, and there are multiple transport strategies that can take advantage of a rapid transit system. In larger metropolitan areas the underground system may extend only to the limits of the central city, or to its inner ring of suburbs with trains making relatively frequent station stops. The outer suburbs may then be reached by a separate commuter-, suburban- or regional rail network, where more widely spaced stations allow a higher speed. These trains are often more expensive, less frequent, and, in some cities, operate only during rush hour periods.
It is common for trapid transit systems to be supplemented with other systems, either busses, trams and/or commuter trains. Because of the high density structure of the rapid transit, short haul trips are often more easilly performed with tram lines or busses. Many cities have chosen to operate a tram system in the city core with the metro expanding beyond it. A typical example of this is Oslo that features a city core transport with trams, the metro streching beyond the core to the city limits and commuter trains serving neighbouring boroughs. Another common strategy is to use a bus feeding system to transport people to the transit stops and use the transits to carry them to the city centre or other bus routes. Using this system highly effectivates the suburban bus system, since they are not required to drive all the way to the city centre.
Elevated railways were a popular way to build mass transit systems in cities around the turn of the twentieth century, but they have fallen out of favour; and many elevated lines were later demolished, being replaced by subways or buses. Elevated rail saw something of a resurgence in the late twentieth century, with the construction of a number of new lines such as the Docklands Light Railway in London and the Bangkok Skytrain and Vancouver SkyTrain; in the United States a few such lines have been built, including the Atlanta's MARTA, New York's AirTrain JFK and the Las Vegas Monorail, but these are typically seen as more futuristic, and are not representative of the overall trends in U.S. transit development, predominently because these cities are building brand new rapid transit systems.
 Integration with commuter trains
Beyond the extent of the metro many cities choose to use commuter trains. Many of these regional railways were first built to operate in one direction from a city centre terminus, but some have been extended across the city centre, sometimes running in tunnels. They offer suburban passengers a choice of stations and also provide useful transportation in the city. A notable example is the Paris RER system, where (in co-operation with the city's transit authority) several pairs of existing suburban lines running in opposite directions from the city have been extended in tunnels to join and form new routes across the city. They are provided with frequent service and, within the city, the same fares as the Métro are charged, providing an integrated network. In Tokyo and Osaka, Japanese private companies operate the world's most extensive suburban railways, each with their own fare system that integrates with the entire system. In German-speaking countries, the Paris style system is called an S-Bahn, in Italian-speaking countries Linea S or Treno Suburbano and in Spanish it is referred to as Cercanías. In Europe these systems are or have often been operated by the state railway.
In some cases the rapid transit system runs to the suburbs and effectively functions as a regional rail service as well. Examples are the San Francisco Bay Area Rapid Transit (BART) and Washington Metrorail systems, though both are supplemented with other commuter train servies. Where there are separate systems, the rapid transit system is typically a self-contained service with its own dedicated tracks and stations and technologically incompatible with other railways. Suburban rail services, on the other hand, often share tracks and stations with long-distance trains (historically they were usually operated by the same company, which also owned the rails and ran freight, although this has become less common) and are subject to the same standards and regulations. There are exceptions; some London Underground lines share tracks with suburban rail services. In some cases, underground railway lines have been extended by taking over existing regional rail lines, notably parts of the Central and Northern Lines in London. The Athens Metro's Blue Line shares tracks with suburban rail services in order to connect the metro to Eleftherios Venizelos International Airport, but does not stop at the suburban rail stations because the platforms of the stations are a lot lower than the train's floor. In Hong Kong and São Paulo, Brazil, metro-like frequent service is provided by electrifying existing railway lines, while continuing to share the tracks with the much less frequent intercity and freight trains. The KCR West Rail in Hong Kong is designed to accommodate intercity and freight traffic in future, whilst at present provides only metro-like service. The Tyne and Wear Metro in the North East of England is another metro service which shares some of its tracks with suburban rail services. The extension of the system to Sunderland sees the metro sharing tracks with Northern train services between Sunderland and Pelaw.
 Similarities to light rail
There has always been some crossover between rapid transit and "lighter" streetcar/tram systems. For example, some lines of the Brooklyn Rapid Transit Company in New York City were elevated in built-up areas and ran at street level, often along streets, in less crowded areas. In many German cities, such as Hanover, the opposite applies, with trams descending into tunnels to cross the city centre.
In the other direction, interurban streetcars provided rapid transit-style transit from cities to suburbs and other cities, running mainly on separate rights-of-way track (sometimes sharing tracks with intercity rail), but using streetcar equipment. Most interurbans have been abandoned, but some (like the Norristown High Speed Line near Philadelphia) have been reconstructed to rapid transit specifications.
Additionally, many streetcar/tram systems include underground and (less commonly) elevated sections, in which everything about the system except the right-of-way is built to streetcar standards. Notably, the first subway in the United States, Boston's Green Line, opened in 1897 to take streetcars off downtown streets, though it did carry elevated trains from 1901 until the Washington Street Tunnel opened. Likewise, San Francisco's Market Street Subway carries Muni Metro light rail on the upper tracks and Bay Area Rapid Transit metro trains on the lower level.
The coming of modern light rail in the 1970s brought new crossovers. New systems were built and old streetcar/tram systems were upgraded with higher capacity and speeds, but retaining some aspects of streetcars and trams. Some systems known as light rail, such as the Docklands Light Railway in London, Manchester Metrolink and New York City's AirTrain JFK, are rapid transit systems but commonly described as light rail. Indeed, in a many Asian countries, light rail is usually used to refer to some sort of rapid transit system but not used to refer to street cars or trams. Other light-rail systems may use high platforms but otherwise run as streetcars. A few systems similar to interurban streetcars have come back, such as New Jersey's River LINE, which operates over freight rails for most of its trip, and along streets on one end. The KCR Light Rail, which runs as streetcars, operates with high platforms, with some of its sections elevated or street level right-of-way, and some at ground-level by away from streets.
 Importance and functions
The volume of passengers a metro train can carry is often quite high, and a metro system is often viewed as the backbone of a large city's public transportation system. In many cities passengers beginning their journeys on a streetcar/tram, bus, or suburban rail system must finish their journey into the city center on the metro, as their first mode of transport will terminate at a metro station to avoid congesting the city center above ground. Budapest is a perfect example where the two more modern metro lines connect with buses and trams and also with two circular streetcar/tram routes (one closer to and one further from the city center) that allow travel between suburbs and also into the centre of the city by changing onto the metro.
In some cities, the urban rail system is so comprehensive and efficient that the majority of city residents use it as their primary means of transport. London, Moscow, New York City, Madrid, Paris, Seoul, Tokyo and Osaka are such examples; these cities have the most extensive and convenient metro systems in the world. With 15 lines, the Tokyo subway is the largest rapid transit network in the world, transporting 7 million passengers daily.<ref>Template:Cite web</ref> The majority of suburban residents in addition to city dwellers do not own automobiles and depend on rail as the primary means of travel. Osaka, Japan is similar to Tokyo's system except about half as big, but still has a ridership exceeding that of New York City. In Europe, London (in 1st place) and Madrid (second) have the biggest metro systems.
Due to a general low population density and a different urban plan, many cities in the United States have very low rates of transit usage. About one in every three users of mass transit in the United States and two-thirds of the nation's rail riders live in just one city: New York<ref>Template:Cite web</ref> (see Transportation in New York City). Older cities such as Chicago, Washington, D.C., Boston, and Philadelphia follow New York, while the rest of the cities in the United States have only partial or poorly-used systems, especially in sunbelt cities such as Phoenix, Los Angeles, Atlanta, Dallas, Las Vegas or Houston.
In the Western Hemisphere, Mexico City also has a large system. In Canada, only Toronto and Montréal have extensive metro networks serving their urban centers; Vancouver's SkyTrain also provides high-grade service, but at present acts primarily as a connection between Vancouver and the surrounding area.
 Alternate uses
Most underground systems are for public transportation, but a few cities have built freight or postal lines. One example was the Post Office Railway, which transported mail underground between sorting offices in London from 1927 until it was abandoned in 2003. Similarly, until the 1970s the London Underground's Circle Line (originally the Metropolitan Railway) transported goods as well as running passenger trains. Another example was the Chicago Tunnel Company, which had a dense grid of tunnels under downtown Chicago. During the Cold War an important secondary function of some underground systems was to provide shelter in case of a nuclear attack.
Urban rail systems have often been used to showcase economic, social, and technological achievements of a nation, especially in the Soviet Union and other Communist countries. With their marble walls, polished granite floors and splendid mosaics, the metro systems of Moscow and St. Petersburg are widely regarded as some of the most beautiful in the world. Modern metro stations in Russia are usually still built with the same emphasis on appearance. Similarly, the Independent Subway System in New York City was built to compete with the private IRT and BMT systems.
Most rapid transit trains are electric multiple units. Power is commonly delivered by a third rail, or in systems without much length in tunnel, by overhead wires, for example the Tyne and Wear Metro in North East England. Most run on conventional steel railway tracks, although some use rubber tires. Crew sizes have decreased throughout history, with some modern systems now running completely unstaffed trains.
The method of tunnel construction used varies from place to place, depending on the situation. Cut-and-cover tunnels are constructed by digging up city streets, which are then rebuilt over the tunnel. Alternatively, tunnel-boring machines can be used to dig deep-bore tunnels.
The first underground railway in the world is the London Underground.<ref>Template:Cite web</ref> London's system was proposed by Charles Pearson, as part of a city improvement plan, after the Thames Tunnel opened. After ten years of discussion, British Parliament authorized the construction of an underground railroad. Construction began in 1860 and was complete in 1863. The first trains that ran were Steam Locomotives<ref> "Subway". Encyclopædia Britannica online. Retrieved on 2006-12-02.</ref>
Boston followed London with the planning of the Boston Subway, adopted by the Boston Transit Commission. Ground broke on March 28, 1895, with the cost of $5 million.<ref>Cudahy, Brian. Cash, Tokens and Transfers: A History of Urban Mass Transit in North America. ISBN 0823212785.</ref> The first section was open in 1897.<ref>D'Eramo, Marco. The Pig and the Skyscraper: Chicago: a History of Our Future. ISBN 1859844987.</ref>
 See also
- Bombardier Advanced Rapid Transit
- Bus rapid transit
- Light rail
- List of rapid transit systems
- Metrophile (A person with a devoted interest in these systems).
- Metro station
- Public transport
- Rubber-tired metro
- Third rail
- Transit fares
- Urban rail transit
 External links
- MetroMapr.com | Interactive Google Maps of the transit systems in Boston, DC, and Philadelphia with search.
- New York City Subway Resources, an extensive site that includes many photos and much information about rapid transit systems in the U.S. and worldwide, in addition to New York City.
- UrbanRail.Net (formerly called metroPlanet) – descriptions of all metro systems in the world, each with a schematic map showing all stations.
- rapidtransit.com, which includes links to operating companies
- Undistorted metro network maps, all at the same scale for comparison.
- More undistorted maps, for all of the systems of North America.
- Metro Bits Subways need not be boring or dreary! Various aspects of the world's metros.
- Monorail Society A group of monorail enthusiasts. Website has extensive resources: technical information, manufacturers, photographs, reports on current monorail systems around the world.
- Mind the Gap "Mind the Gap" in Japanese, Cantonese and Mandarin.
- Memoirs of a subway musician This musician played in the subway stations of NYC, Paris, Prague & Rome.
- Departing subways Short videos from several cities.
- CityRailTransit - real-distance metro maps
- Forms of City Rail: Metro - RER - Interurban
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