Encyclopedia
A
rapid transit,
underground,
subway,
tube,
elevated, or
metro system is a
railway system, usually in an
urban area, with a high capacity and frequency of service, and
grade separation from other traffic.
Characteristics and nomenclature
See also Passenger rail terminology.There is no one term that all
English speakers use for rapid transit or metro systems. This is a reflection on national and regional usage and differing definitions of what characteristics are essential for these systems.
A common definition would be:
- an urban, electric mass transit railway system;
- totally independent from other traffic;
- with high service frequency.
Those who prefer the terms "subway" or "underground" would additionally specify that the tracks and stations are:
- located below street level, in at least the most important places,
so that the streetscape is unaltered by the line's presence. In some cities the word "subway" applies to the entire system, in others only to those parts that are actually underground.
Those who prefer the terms "rapid transit" or "metro" tend to view this as a less important characteristic and include systems that are entirely elevated or at ground level .
Rapid transit systems that are above street level may be called "elevated" systems in the US, often shortened to
el . In the UK, elevated systems are generally classified as light railways such as the
Docklands Light Railway in east London - although not all British light railways are elevated.
For a more comprehensive listing showing names of this kind of system in cities around the world, see the list of rapid transit systems.
Extent
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 hours periods. Sometimes, for political reasons, commuter lines are operated by a separate authority that tends not to co-operate with the city's transit authority .
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. By making multiple stops in the city, they can offer suburban passengers a choice of stations and also provide useful
transportation within the city. A notable example is the
Paris RER system, where several pairs of existing suburban lines running in opposite directions from the city have been extended in tunnel to join up and form new through 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, Japan 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 such a system is called Linea S or Treno Suburbano, where as in Spain it is referred to as
Cercanías.
In some cases, such as the
San Francisco Bay Area Rapid Transit and
Washington Metrorail systems, the rapid transit system runs to the suburbs and effectively functions as a regional rail service as well. 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 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.
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.
Importance, functions, and station design
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 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. In greater
Tokyo, by far the world's most extensive rail system for any
metropolitan area, the region's 15-line subway network is a mere fraction of the over 75 heavy rail lines, transporting well over 20 million people daily, where 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 and
Madrid 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 . Older cities such as
Chicago,
Washington, D.C.,
Boston, and
Philadelphia follow New York distantly, 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
Montreal 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. This will change by 2011, when the second of two new lines will be completed.
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 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.
See also
Metro station.
Technology
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. 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.
History
Before any plans were made for transit systems with underground tunnels and stations, several railway operators built tunnels for their trains, usually to reduce the grade of the railway line. Examples include Trevithick's Tunnel from 1804, built for the Penydarren locomotive.
The
London Underground, usually referred to by Londoners simply as "the Underground" or more familiarly "the Tube", began operations on January 10, 1863 on the
Metropolitan Railway. The Underground currently serves 274
stations and runs over 253
miles of lines. There are also a number of stations and tunnels that are
now closed, some of which can be seen from trains.
A major breakthrough in the development of modern electrically-driven rapid transit occurred when the American inventor
Frank J. Sprague successfully tested his system of multiple-unit train control on the Chicago L in 1897. MUTC, which allowed all the motors in an entire train to be dependably controlled from a single point, freed rapid transit systems from dependence on
locomotive-hauled coaches.
The first underground railway in continental Europe was the
Tünel, an underground 573-meter
funicular between the quarters of
Beyoglu and
Galata in the European part of
Istanbul, completed in 1875 by French engineers on behalf of the
Ottoman Empire. It rarely figures as continental Europe's first metro, though, partly because of its limited length, partly because the cars were pulled by horses until the line was converted to electric operation in 1910. After the Tünel, the first underground railway to be completed in continental Europe was opened in
Budapest in 1896, after only two years of construction. It stretches from Vörösmarty tér to City Park and the local zoo, over a total length of 3.7 km . It is now part of the
Budapest Metro and remains largely in its original state, with the original cars modernised and the stations restored in keeping with their original design, and with the route the same except for a very short extension north to Mexikói út to connect with the city's tram network. It lays claim to a second title, that is the first electric underground railway with overhead cables, like the Newcastle system, rather than the more common third rail in the world. The 10.4 km
Glasgow Subway in
Scotland opened the same year and used cable haulage until it was electrified in 1935.
The first line of the
Paris Metro opened in 1900. Its full name was the
Chemin de Fer Métropolitain, a direct translation into
French of London's
Metropolitan Railway. The name was shortened to
métro, and many other languages have since borrowed this word. The Berlin
U-Bahn opened in 1902; because large sections of the line were elevated, it was also called Hochbahn until the 1920s.
Boston has the oldest subway tunnel in the United States that is still in use, part of the Green Line downtown, dating from 1897. The original construction was a short four-track tunnel downtown, with only two stations, built to take
light rail cars from outlying areas off the streets. Later subways in Boston carried full-size trains; the Green Line still operates with
light rail equipment. In 1901, heavy rail trains began to use the tunnel as part of the original configuration of the Main Line Elevated, the first elevated railway in Boston.
The
New York City Subway, which has become the world's largest , did not open its first section until 1904, but this was a fully independent four-track line, stretching 9 miles from
City Hall to 145th Street. Extensions were soon built, reaching
the Bronx and
Brooklyn; this is now part of the system. Two major subway systems, operated by the and the
IND were constructed later, and many pre-existing
elevated railway lines were incorporated into the and systems. The
Hudson and Manhattan Railroad, which also opened a subway tunnel in
Manhattan in 1908 and connected with
New Jersey, remained a separate railroad company, and later came under the control of the
Port Authority of New York and New Jersey as the
Port Authority Trans-Hudson . New York City subway trains now run on right-of-way first used in 1863, and converted R44 subway cars run on the 1860 Staten Island Railway.
In
Italy the first line was built for the 1906 World Exhibition Fair in
Milan. It was an elevated light rail that linked the two main area of the fair. The line was dismantled eight years later.
In 1907, the first line in
Philadelphia, now part of the
Market-Frankford Line, began running on both elevated and underground structures.
The oldest subway in the
Southern Hemisphere opened in 1913 in
Buenos Aires,
Argentina, which is also the oldest one in
Latin America and the
Spanish-speaking world. The system is now known as
El Subte.
In
Madrid the metro opened on October 17, 1919 under the direction of the Compañía de Metro
Alfonso XIII. Metro stations served as air raid shelters during the
Spanish Civil War.
Asia's oldest commuter heavy rail lines are in Japan, with private companies
Meitetsu railways opening in 1895, and
Tokyo's Keihin Kyuko in 1896, both still serving dense urbanized areas. Asia's first cities to have subway lines are
Tokyo in 1927 and
Osaka in 1933. Japan's rail system is quite different from others in that the vast majority of its rapid transit is above ground, and privately owned and operated, and train stations blur the dinstiction between vast underground malls and corporate skyscrapers and gigantic high rise department stores. Train stations in Japan, like highways in the US, become the center and backbone of town and create their own skyline, especially in suburbs like
Saitama and
Fujisawa. Other major Japanese cities also have subway systems, including
Yokohama,
Nagoya, Sapporo,
Kobe,
Kyoto,
Fukuoka, and
Sendai.
In the past 30 years, a number of cities in Korea have also developed modern and
extensive subway systems. The largest,
Seoul, has nine lines over approximately 178 miles of track .
Busan,
Daegu,
Incheon,
Gwangju and
Daejeon also have subway systems.
China and
India are rapidly expanding their urban rail systems as well.
The first underground in the former
USSR opened in 1935 in
Moscow. The first line — between
Sokolniki and Park Kul'tury — was 11.2 km long. The
Moscow metro was built during the reign of
Stalin, and is one of the most elaborately decorated undergrounds of the world, with its stations often being called
underground palaces. In Russia and other republics of the former Soviet Union as a whole, subways opened in
Saint Petersburg ,
Kiev ,
Tbilisi ,
Baku ,
Kharkov ,
Tashkent ,
Yerevan ,
Minsk ,
Nizhniy Novgorod ,
Novosibirsk ,
Samara ,
Yekaterinburg ,
Dnepropetrovsk ,
Kazan . In
Volgograd and Krivoj Rog in 1980s a "metrotram" opened – it runs underground, along with common city trams.
In 1959, a metro system was inaugurated in
Lisbon, called
Metropolitano de Lisboa. It was the first underground rail system in the
Portuguese-speaking world.
The
Toronto Subway opened in 1954. One experimental trainset consisted of the first aluminum subway cars, which reduced weight and therefore operating costs. With the next car order in 1963, only aluminum was used. The new cars, at 75 feet/23 m, were at the time the longest in the world. The
Montreal Metro, was the second
subway system in
Canada and was inaugurated in 1966 as part of
Expo 67 that would be held in
Montreal.
In
Brazil, the first underground opened in 1974 in
São Paulo, and now carries some four million passengers on an average weekday as part of the
São Paulo Metro. Part of it consists of converted older railways; some of its stations actually date from the 1880s. Underground lines have been built also in
Rio de Janeiro,
Belo Horizonte,
Recife, Porto Alegre and
Brasília.
Metro de Santiago is the metro system serving
Santiago, the capital of the
Republic of Chile. It is a network of five lines with a total of 85 stations.
The
Washington Metro in
Washington, D.C. 
