Rapid transit

Rapid transit

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A rapid transit, underground, subway, elevated railway, metro or metropolitan railway system is an electric
Railway electrification system
A railway electrification system supplies electrical energy to railway locomotives and multiple units as well as trams so that they can operate without having an on-board prime mover. There are several different electrification systems in use throughout the world...

 passenger
Public transport
Public transport is a shared passenger transportation service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement.Public transport modes include buses, trolleybuses, trams...

 railway
Rail transport
Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...

 in an urban area
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...

 with a high capacity and frequency, and grade separation
Grade separation
Grade separation is the method of aligning a junction of two or more transport axes at different heights so that they will not disrupt the traffic flow on other transit routes when they cross each other. The composition of such transport axes does not have to be uniform; it can consist of a...

 from other traffic. Rapid transit systems are typically located either in underground tunnels or on elevated rails above street level. Outside urban centers, rapid transit lines may run on grade separated ground level tracks.

Service on rapid transit systems is provided on designated lines between stations using electric multiple unit
Electric multiple unit
An electric multiple unit or EMU is a multiple unit train consisting of self-propelled carriages, using electricity as the motive power. An EMU requires no separate locomotive, as electric traction motors are incorporated within one or a number of the carriages...

s on rail tracks, although some systems use guided rubber tyres, magnetic levitation
Magnetic levitation
Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields...

, or monorail
Monorail
A monorail is a rail-based transportation system based on a single rail, which acts as its sole support and its guideway. The term is also used variously to describe the beam of the system, or the vehicles traveling on such a beam or track...

. They are typically integrated with other public transport and often operated by the same public transport authorities. Rapid transit is faster and has a higher capacity than tram
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...

s or light rail
Light rail
Light rail or light rail transit is a form of urban rail public transportation that generally has a lower capacity and lower speed than heavy rail and metro systems, but higher capacity and higher speed than traditional street-running tram systems...

, but is not as fast or as far-reaching as commuter rail. It is unchallenged in its ability to transport large amounts of people quickly over short distances with little land use. Variations of rapid transit include people mover
People mover
A people mover or automated people mover is a fully automated, grade-separated mass transit system.The term is generally used only to describe systems serving relatively small areas such as airports, downtown districts or theme parks, but is sometimes applied to considerably more complex automated...

s, small-scale light metro and the commuter rail hybrid S-Bahn
S-Bahn
S-Bahn refers to an often combined city center and suburban railway system metro in Austria, Germany, Switzerland and Denmark...

.

The first rapid transit system was the London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

, which opened in 1863. The technology quickly spread to other cities in Europe, and then to the United States where a number of elevated systems were built. At first these systems used steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

s, with the term later coming to entirely mean electric systems. Since then the largest growth has been in Asia and with driverless systems. More than 160 cities have rapid transit systems, totaling more than 8000 km (4,971 mi) of track and 7,000 stations. Twenty-five cities have new systems under construction.

The biggest metro system in the world by length of routes (including non-revenue trackage) and by number of stations is the New York City Subway
New York City Subway
The New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority, a subsidiary agency of the Metropolitan Transportation Authority and also known as MTA New York City Transit...

; by length of passenger lines, the largest are the Shanghai Metro
Shanghai Metro
The Shanghai Metro is the urban rapid transit system of China's largest city, Shanghai. The system incorporates both subway and light rail lines. It opened in 1995, making Shanghai the third city in Mainland China, after Beijing and Tianjin, to have a rapid transit system...

 and London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

. The busiest metro systems in the world by daily and annual ridership are the Tokyo subway
Tokyo Subway
The is an integral part of the world's most extensive rapid transit system in a single metropolitan area, Greater Tokyo. While the subway system itself is largely within the city center, the lines extend far out via extensive through services onto suburban railway lines.- Networks :As of June...

, Moscow Metro
Moscow Metro
The Moscow Metro is a rapid transit system serving Moscow and the neighbouring town of Krasnogorsk. Opened in 1935 with one line and 13 stations, it was the first underground railway system in the Soviet Union. As of 2011, the Moscow Metro has 182 stations and its route length is . The system is...

 and Seoul Metropolitan Subway
Seoul Metropolitan Subway
The Seoul Metropolitan Subway or Metropolitan Subway in Seoul, in Seoul, South Korea, is one of the most heavily used rapid transit systems in the world, with well over 8 million trips daily on the system's thirteen lines...

.
__toc__

Terminology




Metro is the most common term for underground rapid transit systems. Rapid transit systems may be named after the medium through which their busier inner-city sections travel: use of tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

s inspires names such as subway, underground, Untergrundbahn (U-bahn) in German, or Tunnelbana (T-bana) in Swedish; use of viaduct
Viaduct
A viaduct is a bridge composed of several small spans. The term viaduct is derived from the Latin via for road and ducere to lead something. However, the Ancient Romans did not use that term per se; it is a modern derivation from an analogy with aqueduct. Like the Roman aqueducts, many early...

s inspires names such as elevated (el or L), skytrain, overhead or overground. One of these terms may apply to an entire system, even if a large part of the network (for example, in outer suburbs) runs on ground level.

In English English a subway is a pedestrian underpass, so the expressions underground and tube may be preferred. In Scotland, Glasgow's underground rapid transit system is called the Glasgow Subway
Glasgow Subway
The Glasgow Subway is an underground metro line in Glasgow, Scotland. Opened on 14 December 1896, it is the third-oldest underground metro system in the world after the London Underground and the Budapest Metro. Formerly a cable railway, the Subway was later electrified, but its twin circular lines...

.

History


Rapid transit evolved from steam railways during the late 19th century. In 1890 the City & South London Railway
City & South London Railway
The City and South London Railway was the first deep-level underground "tube" railway in the world, and the first major railway to use electric traction...

 in London was the first electric rapid transit railway. The electric railway eventually was merged into London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

. The technology swiftly spread to other cities in Europe, as in Budapest
Budapest
Budapest is the capital of Hungary. As the largest city of Hungary, it is the country's principal political, cultural, commercial, industrial, and transportation centre. In 2011, Budapest had 1,733,685 inhabitants, down from its 1989 peak of 2,113,645 due to suburbanization. The Budapest Commuter...

, Hungary in 1896, and then to the United States. A number of elevated systems were built, starting with the 1893 100% designed electric Liverpool Overhead Railway
Liverpool Overhead Railway
The Liverpool Overhead Railway was the world's first electrically operated overhead railway. The railway was carried mainly on iron viaducts, with a corrugated iron decking, onto which the tracks were laid. It ran close to the River Mersey in Liverpool, England, following the line of Liverpool Docks...

. The elevated railways in Chicago and New York
IRT Ninth Avenue Line
The IRT Ninth Avenue Line, often called the Ninth Avenue El, was the first elevated railway in New York City. It opened in 1868 as the West Side and Yonkers Patent Railway, a cable-hauled line. It ceased operation in 1940....

 were converted to electric from steam propulsion.

By 1940, there were 19 systems, and by 1984, there were 66. This included smaller cities like Oslo
Oslo T-bane
The Oslo Metro is the rapid transit system of Oslo, Norway, operated by Oslo T-banedrift on contract from the transit authority Ruter. The network consists of six lines that all run through the city centre, with a total length of . It has a daily ridership of 268,000 with 105 stations of which 16...

 and Marseille
Marseille Metro
The Marseille metro serves the City of Marseille. It is a rubber-tyred metro derived from the technology developed by the RATP for Paris Metro and opened at the end of 1977...

 which opened extensive systems in the 1960s. More recently the growth of new systems has been concentrated in Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

 and Latin America
Latin America
Latin America is a region of the Americas where Romance languages  – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...

. Western Europe
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...

 and North America have instead seen a revival of the tram, with light rail
Light rail
Light rail or light rail transit is a form of urban rail public transportation that generally has a lower capacity and lower speed than heavy rail and metro systems, but higher capacity and higher speed than traditional street-running tram systems...

 systems supplementing full scale urban railways, and less focus on building rapid transit. At the same time, technological improvements have allowed new driverless lines and systems. Hybrid solutions have also evolved, such as tram-train
Tram-train
A tram-train is a light-rail public transport system where trams run both on an urban tramway network and on main-line railways to combine the tram's flexibility and availability and the train's greater speed...

 and premetro
Premetro
A premetro is a tramway or light railway which includes segments built to rapid transit standards, usually as part of a process of conversion to a metro railway, mainly by the construction of tunnels in the central city area...

, which have some of the features of rapid transit systems.

Operation



Rapid transit is used in cities
City
A city is a relatively large and permanent settlement. Although there is no agreement on how a city is distinguished from a town within general English language meanings, many cities have a particular administrative, legal, or historical status based on local law.For example, in the U.S...

, agglomeration
Agglomeration
In the study of human settlements, an urban agglomeration is an extended city or town area comprising the built-up area of a central place and any suburbs linked by continuous urban area. In France, INSEE the French Statistical Institute, translate it as "Unité urbaine" which means continuous...

s and metropolitan area
Metropolitan area
The term metropolitan area refers to a region consisting of a densely populated urban core and its less-populated surrounding territories, sharing industry, infrastructure, and housing. A metropolitan area usually encompasses multiple jurisdictions and municipalities: neighborhoods, townships,...

s to transport large numbers of people at high frequency. The extent of the rapid transit system varies greatly between cities, with several transport strategies: in larger metropolitan areas the underground system may extend only to the limits of the inner city, or to its inner ring of suburb
Suburb
The word suburb mostly refers to a residential area, either existing as part of a city or as a separate residential community within commuting distance of a city . Some suburbs have a degree of administrative autonomy, and most have lower population density than inner city neighborhoods...

s with trains making frequent station stops. The outer suburbs may then be reached by a separate commuter rail network, where more widely spaced stations allow higher speeds. These trains are often more expensive and less frequent, and in some cities operate only during rush hour
Rush hour
A rush hour or peak hour is a part of the day during which traffic congestion on roads and crowding on public transport is at its highest. Normally, this happens twice a day—once in the morning and once in the evening, the times during when the most people commute...

 periods. They may or may not satisfy the criteria for an urban rapid transit system, and in some cases the differences between urban and suburban rapid transit systems are not clear. See also the Variations and Comparison sections below.
Rapid transit systems are often supplemented by other systems, either bus
Bus
A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...

es, tram
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...

s or commuter rail. This combination of transit modes serves to offset certain limitations of rapid transit, such as limited stops and long walking distances within station infrastructure between outside access points and the vehicle itself, (sometimes involving long vertical distances if the station is in a deep-level tunnel or on a high overpass). Given these limitations, combined with the high density nature of many urban environments, short trips are often more easily performed on trams or buses. Many cities have chosen to operate a tram system in the city core with the metro expanding beyond it, although many cities (especially outside of Europe) later converted their surface systems from trams to buses in the 1950s and 60s. Another common strategy is to use a bus or tram feeder system to transport people to rapid transit stops, freeing the suburban or feeder system from the requirement to drive all the way to the city centre. Surface route terminals connected directly to rapid transit stations, provided especially in newer systems with single, consolidated transit agencies turn rapid transit stations into neighbourhood centres - nodes of activity that can blossom into satellite business districts of their own. This scheme promotes transit ridership in lower-density outlying neighbourhoods that do not have the population density or sufficient attractions to support their own rapid transit lines by offering a connection to business districts that saves users from driving in big city traffic conditions, and reduces congestion in urban centres by consolidating passengers into dedicated high-frequency, high-capacity corridors, instead of being reliant on city centre streets, which are often among the oldest in their respective cities and were often never designed to accommodate modern traffic volumes.

In Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...

, over 50% of its rapid transit
Toronto subway and RT
The Toronto subway and RT is a rapid transit system in Toronto, Ontario, Canada, consisting of both underground and elevated railway lines, operated by the Toronto Transit Commission . It was Canada's first completed subway system, with the first line being built under Yonge Street, which opened in...

 stations have bus and streetcar
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...

 terminals within the fare-paid zone, providing a connection without requiring proof-of-payment, and speeding boarding by allowing passengers to board through all doors. Several subway stations, especially current or former termini for their respective lines, have developed significant satellite commercial districts of their own.

Rapid transit systems have high fixed cost
Fixed cost
In economics, fixed costs are business expenses that are not dependent on the level of goods or services produced by the business. They tend to be time-related, such as salaries or rents being paid per month, and are often referred to as overhead costs...

s. Most systems are publicly owned, by either local governments, transit authorities or national governments. Investments are often financed by taxation, rather than by passengers, but must often compete with funding for road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...

s. The systems may be operated by the owner or by a private company through a public service obligation
Public Service Obligation
In transport, public service obligation or PSO is an arrangement in which a governing body or other authority offers an auction for subsidies, permit the winning company a monopoly to operate a specified service of public transport for a specified period of time for the given subsidy...

. The owners of the systems often also own the connecting bus or rail systems, or are members of the local transport association
Transport association
In the United Kingdom and other countries, a transport association is an association of public transport authorities in a large urban area. The modes of transport can include both private and government owned bodies.In aims of a transport association are...

, allowing for free transfers between modes. Almost all systems operate at a deficit, requiring fare revenue, advertising
Advertising
Advertising is a form of communication used to persuade an audience to take some action with respect to products, ideas, or services. Most commonly, the desired result is to drive consumer behavior with respect to a commercial offering, although political and ideological advertising is also common...

 and subsidies
Subsidy
A subsidy is an assistance paid to a business or economic sector. Most subsidies are made by the government to producers or distributors in an industry to prevent the decline of that industry or an increase in the prices of its products or simply to encourage it to hire more labor A subsidy (also...

 to cover costs. The farebox recovery ratio
Farebox recovery ratio
The farebox recovery ratio of a passenger transportation system is the proportion of the amount of revenue generated through fares by its paying customers as a fraction of the cost of its total operating expenses....

, a ratio of ticket income to operating costs, is often used to assess operational profitability, with some systems including Hong Kong's MTR Corporation
MTR Corporation
MTR Corporation Limited is a company listed on the Hong Kong Exchange and included in the Hang Seng Index. MTR owns and runs the Hong Kong MTR metro system, and is also a major property developer and landlord in Hong Kong...

, and Taipei
Taipei Rapid Transit System
The Taipei Metro, more commonly known as the MRT or formally as the Taipei Rapid Transit System, is a rapid transit system serving metropolitan Taipei in Taiwan. The system is built and operated by the Taipei Rapid Transit Corporation and consists of 89 stations and of revenue track...

 achieving recovery ratios of well over 100%. This ignores both heavy capital costs incurred in building the system, which are often subsidized with soft loans and whose servicing
Loan servicing
Loan servicing is the process by which a mortgage bank or subservicing firm collects the timely payment of interest and principal from borrowers...

 is excluded from calculations of profitability, as well as ancillary revenue such as income from real estate
Real estate
In general use, esp. North American, 'real estate' is taken to mean "Property consisting of land and the buildings on it, along with its natural resources such as crops, minerals, or water; immovable property of this nature; an interest vested in this; an item of real property; buildings or...

 portfolios. Some metros, including Hong Kong, are even financed by the sale of land whose value has been increased by the building of the system.

Lines


Each rapid transit system consists of one or more lines. Each line is serviced by at least one specific route with trains stopping at all or some of the line's stations. Most systems operate several routes, and distinguish them by colors, names, numbering, or a combination thereof. Some lines may share track with each other for a portion of their route, or operate solely on their own right-of-way. Often a line running through the city center forks into two or more branches in the suburbs, allowing a higher service frequency in the center. This arrangement is used by many systems, such as the Copenhagen Metro
Copenhagen Metro
Copenhagen Metro is a rapid transit system serving Copenhagen, Frederiksberg and Tårnby in Denmark. The system opened between 2002 and 2007, and has two lines, M1 and M2. The driverless light metro supplements the larger S-train rapid transit system, and is integrated with DSB local trains and...

. Alternatively there might be a single central terminal (often shared with the central railway station), or multiple interchange stations between lines in the city centre, for instance in the Prague Metro
Prague Metro
The Prague Metro is a subway, underground public transportation network in Prague, Czech Republic. It is the fastest means of transportation around the city and serves about one and a half million passengers a day, which makes it the seventh busiest metro system in Europe and the most-used in the...

. The London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...


and Paris Métro
Paris Métro
The Paris Métro or Métropolitain is the rapid transit metro system in Paris, France. It has become a symbol of the city, noted for its density within the city limits and its uniform architecture influenced by Art Nouveau. The network's sixteen lines are mostly underground and run to 214 km ...

 are densely built systems with a matrix of crisscrossing lines throughout the cities. Other systems, such as the New York City Subway
New York City Subway
The New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority, a subsidiary agency of the Metropolitan Transportation Authority and also known as MTA New York City Transit...

  are also densely built and their layout facilitate trips to a central area, such as Manhattan
Manhattan
Manhattan is the oldest and the most densely populated of the five boroughs of New York City. Located primarily on the island of Manhattan at the mouth of the Hudson River, the boundaries of the borough are identical to those of New York County, an original county of the state of New York...

, the city's business and cultural center. The Chicago 'L'
Chicago 'L'
The L is the rapid transit system serving the city of Chicago and some of its surrounding suburbs. It is operated by the Chicago Transit Authority...

 has most of its lines converging on The Loop, the main business, financial, and cultural section. Some systems have a circle line around the city center connecting the radially arranged outward lines, such as the Moscow Metro
Moscow Metro
The Moscow Metro is a rapid transit system serving Moscow and the neighbouring town of Krasnogorsk. Opened in 1935 with one line and 13 stations, it was the first underground railway system in the Soviet Union. As of 2011, the Moscow Metro has 182 stations and its route length is . The system is...

's Koltsevaya Line
Koltsevaya Line
The Koltsevaya Line , , is a railway line of the Moscow Metro. The line was built in 1950-1954 encircling the central Moscow, and became crucial to the transfer patterns of passengers....

 and Tokyo's Yamanote Line
Yamanote Line
The is commuter rail loop line in Tokyo, Japan, operated by East Japan Railway Company . It is one of Tokyo's busiest and most important lines, connecting most of Tokyo's major stations and urban centres, including the Yūrakuchō/Ginza area, Shibuya, Shinjuku, and Ikebukuro, with all but two of its...

.

The capacity of a line is obtained by multiplying together the car capacity, train length and service frequency
Headway
Headway is a measurement of the distance/time between vehicles in a transit system. The precise definition varies depending on the application, but it is most commonly measured as the distance from the tip of one vehicle to the tip of the next one behind it, expressed as the time it will take for...

. Heavy rapid transit trains might have six to twelve cars, while lighter systems may use only four or fewer cars. Cars have a capacity of 100 to 150, varying with the seated to standing ratio
Seated to standing ratio
The seated to standing ratio is the ratio between the number of passengers that can be seated and the number of standing passengers on a public transport vehicle. A higher standing ratio allows for more passengers in a given area, but detracts the perceived quality of the transport, in particular...

—more standing gives higher capacity. Bilevel car
Bilevel car
The bilevel car or double-decker coach is a type of rail car that has two levels of passenger accommodation, as opposed to one, increasing passenger capacity ....

s, used mostly on German S-Bahn type systems, have more space, allowing the higher seated capacity needed on longer journeys. The minimum time interval between trains is shorter for rapid transit than for mainline railways owing to the use of block signaling: the minimum headway might be 90 seconds, which might be limited to 120 seconds to allow for recovery from delays. Typical capacity lines allow 1200 people per train, giving 36,000 people per hour. The highest attained capacity is 80,000 people per hour by the MTR Corporation
MTR Corporation
MTR Corporation Limited is a company listed on the Hong Kong Exchange and included in the Hang Seng Index. MTR owns and runs the Hong Kong MTR metro system, and is also a major property developer and landlord in Hong Kong...

 in Hong Kong.

Passenger information



Rapid transit operators often have built up strong brand
Brand
The American Marketing Association defines a brand as a "Name, term, design, symbol, or any other feature that identifies one seller's good or service as distinct from those of other sellers."...

s; in particular the use of a single letter as a station sign has become widespread, with systems identified by the letters L, M, S, T and U, among others. Branding has focused on easy recognition—to allow quick identification even in the vast array of signage found in large cities—combined with the need to communicate speed, safety and authority. In many cities, there is a single corporate image
Corporate image
A corporate image refers to how a corporation is perceived. It is a generally accepted image of what a company stands for. Marketing experts who use public relations and other forms of promotion to suggest a mental picture to the public...

 for the entire transit authority, but the rapid transit uses its own logo that fits into the profile.

A transit map is a topological map
Topological map
In cartography and geology, a topological map is one that has been simplified so that only vital information remains and unnecessary detail has been removed. These maps lack scale, and distance and direction are subject to change and variation, but the relationship between points is maintained...

 or schematic
Schematic
A schematic diagram represents the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the information the schematic is intended to convey, and may add unrealistic elements that aid comprehension...

 diagram
Diagram
A diagram is a two-dimensional geometric symbolic representation of information according to some visualization technique. Sometimes, the technique uses a three-dimensional visualization which is then projected onto the two-dimensional surface...

 used to show the routes and stations in a public transport
Public transport
Public transport is a shared passenger transportation service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement.Public transport modes include buses, trolleybuses, trams...

 system. The main components are color-code
Color-coding
In computer science and graph theory, the method of color-coding efficiently finds k-vertex simple paths, k-vertex cycles, and other small subgraphs within a given graph using probabilistic algorithms, which can then be derandomized and turned into deterministic algorithms...

d lines to indicate each line or service, with named icons to indicate stations. Maps may show only the rapid transit, or also include other modes of public transport.

Transit maps can be found in the transit vehicles, on the platforms
Railway platform
A railway platform is a section of pathway, alongside rail tracks at a train station, metro station or tram stop, at which passengers may board or alight from trains or trams. Almost all stations for rail transport have some form of platforms, with larger stations having multiple platforms...

, elsewhere in stations and in printed timetables
Public transport timetable
A public transport timetable is a representation of public transport information to assist a passenger with planning a trip using public transport. A timetable details when vehicle will arrive and depart specified locations and may be organised for by route or for a particular stop...

. Their primary function is to help users of the system: for instance they show the interchange
Interchange station
An interchange station or a transfer station is a train station for more than one railway route in a public transport system, and allows passengers to change from one route to another. Transfer may occur within the same mode, or between rail modes, or to buses...

 stations where passengers can transfer between lines. Unlike conventional maps, transit maps are usually not geographically accurate: instead they use straight lines and fixed angles, and often a fixed distance between stations, to simplify the display of the system. Often this has the effect of compressing stations in the outer area of the system and expanding those close to the center. Timetables are mostly only published if the service frequency is so low that passengers can profitably time their arrival at the station; if the service is frequent enough (say 6 or more trains an hour) passengers will never have to wait long, and will not need a timetable.

Safety and security



Rapid transits are a public space, and may suffer from security
Security
Security is the degree of protection against danger, damage, loss, and crime. Security as a form of protection are structures and processes that provide or improve security as a condition. The Institute for Security and Open Methodologies in the OSSTMM 3 defines security as "a form of protection...

 problems: petty crimes such as pickpocketing
Pickpocketing
Pickpocketing is a form of larceny that involves the stealing of money or other valuables from the person of a victim without their noticing the theft at the time. It requires considerable dexterity and a knack for misdirection...

 and baggage theft, and more serious crimes such as violence
Violence
Violence is the use of physical force to apply a state to others contrary to their wishes. violence, while often a stand-alone issue, is often the culmination of other kinds of conflict, e.g...

. Security measures include video surveillance, security guard
Security guard
A security guard is a person who is paid to protect property, assets, or people. Security guards are usually privately and formally employed personnel...

s and conductors
Conductor (transportation)
A conductor is a member of a railway train's crew that is responsible for operational and safety duties that do not involve the actual operation of the train. The title of conductor is most associated with railway operations in North America, but the role of conductor is common to railways...

. In some countries a transit police
Transit police
Transit police are a specialized police agency or unit employed by a common carrier, which could be a transit district, railroad, bus line, other transport carrier, or the state...

 may be established. These security measures are normally integrated with measures to protect revenue by checking that passengers are not traveling without paying. Rapid transits have been subject to terrorism
Terrorism
Terrorism is the systematic use of terror, especially as a means of coercion. In the international community, however, terrorism has no universally agreed, legally binding, criminal law definition...

 with many casualties, such as The 1995 Tokyo subway sarin gas attack.
Compared to other modes of transport, rapid transit has a good safety
Safety
Safety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be...

 record, with few accidents. Rail transport is subject to strict safety regulation
Safety
Safety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be...

s, with requirements for procedure and maintenance to minimize risk. Head-on collision
Head-on collision
A head-on collision is one where the front ends of two ships, trains, planes or vehicles hit each other, as opposed to a side collision or rear-end collision.-Rail transport:...

s are rare due to use of double track, and low operating speeds reduce the occurrence and severity of rear-end collision
Rear-end collision
A rear-end collision is a traffic accident wherein a vehicle crashes into the vehicle in front of it, usually caused by tailgating or panic stops...

s and derailment
Derailment
A derailment is an accident on a railway or tramway in which a rail vehicle, or part or all of a train, leaves the tracks on which it is travelling, with consequent damage and in many cases injury and/or death....

s. Fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

 is more of a danger underground, and systems are built to allow evacuation of trains at many places throughout the system.

Infrastructure



Most rapid transit trains are electric multiple units with lengths from three to beyond ten cars. Power is commonly delivered by a third rail
Third rail
A third rail is a method of providing electric power to a railway train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost...

 or by overhead wires, the whole London Underground network uses fourth rail and others use the linear motor
Linear motor
A linear motor is an electric motor that has had its stator and rotor "unrolled" so that instead of producing a torque it produces a linear force along its length...

 for propulsion. Most run on conventional steel railway tracks, although some use rubber tires
Rubber-tyred metro
A rubber-tyred metro is a form of rapid transit system that uses a mix of road and rail technology. The vehicles have wheels with rubber tyres which run on rolling pads inside guide bars for traction, as well as traditional railway steel wheels with deep flanges on steel tracks for guidance through...

 such as the Montreal Metro
Montreal Metro
The Montreal Metro is a rubber-tired metro system, and the main form of public transportation underground in the city of Montreal, Quebec, Canada....

 and Mexico City Metro
Mexico City Metro
The Mexico City Metro , officially called Sistema de Transporte Colectivo, is a metro system that serves the metropolitan area of Mexico City...

. Rubber tires allow steeper gradients and a softer ride, but have higher maintenance costs and are less energy efficient. They also lose friction when weather conditions are wet or icy, preventing above ground use of the Montréal Metro but not rubber-tired systems in other cities. Crew sizes have decreased throughout history with some modern systems now running completely unstaffed trains. Other trains continue to have drivers, even if their only role in normal operation is to open and close the doors of the trains at stations.

Variations


Underground tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

s move traffic away from street level, leaving more land available for buildings and other uses. In areas of high land prices and dense land use, tunnels may be the only economic route for mass transportation. 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 that lie further down in bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

.

Street level railways are used only outside dense areas, since they create a physical barrier that hinders the flow of people and vehicles across their path. This method of construction is the cheapest, as long as land values are low. It is often used for new systems in areas that are planned to fill up with buildings after the line is built.

Elevated railways are a cheap and easy way to build an exclusive right-of-way without digging expensive tunnels or creating barriers. They were popular around the beginning of the 20th century, but fell out of favor; they came back into fashion in the last quarter of the century—often in combination with driverless systems, for instance Vancouver's SkyTrain, London's Docklands Light Railway
Docklands Light Railway
The Docklands Light Railway is an automated light metro or light rail system opened on 31 August 1987 to serve the redeveloped Docklands area of London...

 and the Bangkok Skytrain
Bangkok Skytrain
The Bangkok Mass Transit System, commonly known as the BTS Skytrain , is an elevated rapid transit system in Bangkok, Thailand. It is operated by Bangkok Mass Transit System Public Company Limited under a concession granted by the Bangkok Metropolitan Administration...

.


People mover
People mover
A people mover or automated people mover is a fully automated, grade-separated mass transit system.The term is generally used only to describe systems serving relatively small areas such as airports, downtown districts or theme parks, but is sometimes applied to considerably more complex automated...

 systems are self-contained rapid transit systems serving relatively small areas such as airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...

s, downtown (central) districts or theme parks, either as independent systems or as shuttle services feeding other transport systems. They are usually driverless and normally elevated. Monorail
Monorail
A monorail is a rail-based transportation system based on a single rail, which acts as its sole support and its guideway. The term is also used variously to describe the beam of the system, or the vehicles traveling on such a beam or track...

s have been built as both conventional rapid transits and as people movers, either elevated or underground. Monorail technology has proved difficult to commercialize and its use has been limited. The Berlin M-Bahn
M-Bahn
The M-Bahn or Magnetbahn was an elevated Maglev train line operating in Berlin, Germany in 1991. The line was 1.6 km in length, and featured three stations, two of which were newly constructed...

 was the only commercial maglev rapid transit to operate, but has been closed.

Light metro
Medium-capacity rail transport system
In rail transport, a medium-capacity system is a non-universal term coined to differentiate an intermediate system between light rail and heavy rail. The concept is similar to Light Metro, seen in European countries...

 is used when the speed of rapid transit is desired, but for smaller passenger numbers. It often has smaller trains, of typically two to four cars, lower frequency and longer distances between stations, though it remains grade separated. Light metros are sometimes used as shuttles
Public transport
Public transport is a shared passenger transportation service which is available for use by the general public, as distinct from modes such as taxicab, car pooling or hired buses which are not shared by strangers without private arrangement.Public transport modes include buses, trolleybuses, trams...

 feeding into the main rapid transit system. Some systems have been built from scratch, others are former commuter rail or suburban tramway systems that have been upgraded, and often supplemented with an underground or elevated downtown section.

Stations



Stations function as hubs to allow passengers to board and disembark from trains. They are also payment checkpoints and allow passengers to transfer between modes of transport, for instance to buses or other trains. Access is provided via either island-
Island platform
An island platform is a station layout arrangement where a single platform is positioned between two tracks within a railway station, tram stop or transitway interchange...

 or side platform
Side platform
A Side platform is a platform positioned to the side of a pair of tracks at a railway station, a tram stop or a transitway. A pair of side platforms are often provided on a dual track line with a single side platform being sufficient for a single track line...

s. Underground stations, especially deep-level ones, increase the overall transport time: long escalator
Escalator
An escalator is a moving staircase – a conveyor transport device for carrying people between floors of a building. The device consists of a motor-driven chain of individual, linked steps that move up or down on tracks, allowing the step treads to remain horizontal.Escalators are used around the...

 rides to the platforms mean that the stations can become bottlenecks if not adequately built. Some underground stations are integrated into shopping centers, or have underground access to large nearby commercial buildings. In suburbs, there may be a "park and ride
Park and ride
Park and ride facilities are car parks with connections to public transport that allow commuters and other people wishing to travel into city centres to leave their vehicles and transfer to a bus, rail system , or carpool for the rest of their trip...

" connected to the station.

To allow easy access to the trains, the platform height
Railway platform height
On a railway the platform height refers to the height of a platform above the rail. The value varies between railway systems. A related term is "train floor height" which is the height of the floor of the rail vehicle. There are a wide number of standards for platform heights and train floor heights...

 allows step-free access between platform and train. If the station complies with accessibility
Accessibility
Accessibility is a general term used to describe the degree to which a product, device, service, or environment is available to as many people as possible. Accessibility can be viewed as the "ability to access" and benefit from some system or entity...

 standards, it allows both disabled people and those with wheeled baggage easy access to the trains, though if the track is curved there can be a gap
Mind the gap
"Mind the gap" is a warning to train passengers to take caution while crossing the gap between the train door and the station platform. It was introduced in 1969 on the London Underground...

 between the train and platform. Some stations use platform screen doors
Platform screen doors
Platform screen doors and platform edge doors at train or subway stations screen the platform from the train. They are a relatively new addition to many metro systems around the world, with some platform doors retrofitted rather than installed with the metro system itself. They are widely used in...

 to increase safety by preventing people falling onto the tracks, as well as reducing ventilation costs.
Particularly in the former Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 and other Eastern European countries, but to an increasing extent elsewhere, the stations were built with splendid decorations such as marble walls, polished granite floors and mosaics—thus exposing the public to art in their everyday life, outside galleries and museums. The systems in Moscow
Moscow Metro
The Moscow Metro is a rapid transit system serving Moscow and the neighbouring town of Krasnogorsk. Opened in 1935 with one line and 13 stations, it was the first underground railway system in the Soviet Union. As of 2011, the Moscow Metro has 182 stations and its route length is . The system is...

 and St. Petersburg
Saint Petersburg Metro
The Saint Petersburg Metro is the underground railway system in Saint Petersburg and Leningrad Oblast, Russia. It has been open since November 15, 1955.Formerly known as the V.I...

 are widely regarded as some of the most beautiful in the world, but several other cities such as Stockholm
Stockholm Metro
The Stockholm Metro is a metro system in Stockholm, Sweden. The first line opened in 1950, and today the system has 100 stations in use, of which 47 are underground and 53 above ground. There are seven lines numbered from 10 to 19, in three groups identified by a color: the Green, Red and Blue lines...

, Montreal
Montreal Metro
The Montreal Metro is a rubber-tired metro system, and the main form of public transportation underground in the city of Montreal, Quebec, Canada....

, Lisbon
Lisbon Metro
The Lisbon Metro is the metro system of Lisbon, Portugal. Opened in December 1959, it was the first subway system in Portugal.As of 2011, the four Lisbon subway lines total about in length and comprise 52 stations.- History :- Idea :...

, and Los Angeles
Los Angeles County Metropolitan Transportation Authority
The Los Angeles County Metropolitan Transportation Authority is the California state-chartered regional transportation planning agency and public transportation operating agency for the County of Los Angeles formed in 1993 out of a merger of the Southern California Rapid Transit District and the...

 have also focused on art, which may range from decorative wall claddings, to large, flamboyant artistic schemes integrated with station architecture, to displays of ancient artifacts recovered during station construction. It may be possible to profit by attracting more passengers by spending relatively small amounts on grand architecture
Architecture
Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art...

, art, cleanliness
Cleanliness
Cleanliness is both the abstract state of being clean and free from dirt, and the process of achieving and maintaining that state.Cleanliness may be endowed with a moral quality, as indicated by the aphorism "cleanliness is next to godliness," and may be regarded as contributing to other ideals...

, accessibility
Accessibility
Accessibility is a general term used to describe the degree to which a product, device, service, or environment is available to as many people as possible. Accessibility can be viewed as the "ability to access" and benefit from some system or entity...

, lighting
Lighting
Lighting or illumination is the deliberate application of light to achieve some practical or aesthetic effect. Lighting includes the use of both artificial light sources such as lamps and light fixtures, as well as natural illumination by capturing daylight...

 and a feeling of safety
Safety
Safety is the state of being "safe" , the condition of being protected against physical, social, spiritual, financial, political, emotional, occupational, psychological, educational or other types or consequences of failure, damage, error, accidents, harm or any other event which could be...

.

Comparison


Since the 1980s tram
Tram
A tram is a passenger rail vehicle which runs on tracks along public urban streets and also sometimes on separate rights of way. It may also run between cities and/or towns , and/or partially grade separated even in the cities...

s have incorporated several features of rapid transit: light rail
Light rail
Light rail or light rail transit is a form of urban rail public transportation that generally has a lower capacity and lower speed than heavy rail and metro systems, but higher capacity and higher speed than traditional street-running tram systems...

 systems (trams) run on their own rights-of-way, thus avoiding congestion
Traffic congestion
Traffic congestion is a condition on road networks that occurs as use increases, and is characterized by slower speeds, longer trip times, and increased vehicular queueing. The most common example is the physical use of roads by vehicles. When traffic demand is great enough that the interaction...

; they remain on the same level as buses and cars. Some light rail systems have elevated or underground sections. Both new and upgraded tram systems allow faster speed and higher capacity, and are a cheap alternative to construction of rapid transit, especially in smaller cities.


Premetro
Premetro
A premetro is a tramway or light railway which includes segments built to rapid transit standards, usually as part of a process of conversion to a metro railway, mainly by the construction of tunnels in the central city area...

 means that an underground rapid transit is built in the city center, but only a light rail or tram system in the suburbs. Conversely, other cities have opted to build a full metro in the suburbs, but run trams in city streets to save the cost of expensive tunnels. In North America, interurban
Interurban
An interurban, also called a radial railway in parts of Canada, is a type of electric passenger railroad; in short a hybrid between tram and train. Interurbans enjoyed widespread popularity in the first three decades of the twentieth century in North America. Until the early 1920s, most roads were...

s were constructed as street-running suburban trams, without the grade-separation of rapid transit. Premetros also allow a gradual upgrade of existing tramways to rapid transit, thus spreading the investment costs over time. They are most common in Germany with the name Stadtbahn
Stadtbahn
A ' is a tramway or light railway that includes segments built to rapid transit standards, usually as part of a process of conversion to a metro railway, mainly by the building of tunnels in the central city area....

.
Suburban Commuter rail is a heavy rail system that operates at a lower frequency than urban rapid transit, with higher average speeds, often only serving one station in each village and town. Commuter rails of some cities (such as German S-Bahn
S-Bahn
S-Bahn refers to an often combined city center and suburban railway system metro in Austria, Germany, Switzerland and Denmark...

s, Merseyrail
Merseyrail
Merseyrail is a train operating company and commuter rail network in the United Kingdom, centred on Liverpool, Merseyside. The network is predominantly electric with diesel trains running on the City Line. Two City Line branches are currently being electrified on the overhead wire AC system with...

, Chennai rail
Chennai suburban railway
Chennai suburban railway is a commuter rail system in the Indian city of Chennai operated by the Southern Railway. Chennai has a complex railway network. The system uses electrical multiple units operating on alternating current drawn from over-head cables through the catenary system...

, Australian cityrails
Rail transport in Australia
Rail transport in Australia is a crucial aspect of the Australian transport network, and an enabler of the wider Australian economy. Rail in Australia is to a large extent state-based. The Australian rail network consists of a total of 41,461 km of track of three major gauges, of which...

 (Transperth
Transperth
Transperth is the brand name of the public transport system in Perth, Western Australia. It is operated by the Public Transport Authority.-History:...

, Metro Trains Melbourne
Metro Trains Melbourne
Metro Trains Melbourne is the current franchise operator of the suburban railway network of Melbourne, Australia. Metro Trains Melbourne is a joint venture led by Hong Kong based MTR Corporation together with John Holland Group and United Group Rail .Metro Trains Melbourne operates a fleet of 381...

, Queensland Rail
Queensland Rail
Queensland Rail, also known as QR, is a government-owned railway operator in the state of Queensland. Under the control of the Queensland Government, Queensland Rail operates the inner-city and long-distance passenger services, as well as some freight operations and gives railway access to other...

 (Brisbane
Brisbane
Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...

), CityRail
CityRail
CityRail is an operating brand of RailCorp, a corporation owned by the state government of New South Wales, Australia. It is responsible for providing commuter rail services, and some coach services, in and around Sydney, Newcastle and Wollongong, the three largest cities of New South Wales. It is...

 (Sydney)), Danish S-tog
S-Train
The S-train network is a combined urban rapid transit and suburban rail network of Metropolitan Copenhagen, Denmark. It connects the city center with the inner suburbs of Copenhagen, and has close to half of the stations within the urban city. The first line was opened in 1934...

 etc. widely provide a mass transit within city as urban metro systems. As opposition, in some cities (such as PATH
Port Authority Trans-Hudson
PATH, derived from Port Authority Trans-Hudson, is a rapid transit railroad linking Manhattan, New York City with Newark, Harrison, Hoboken and Jersey City in metropolitan northern New Jersey...

 in New York, Dubai Metro
Dubai Metro
The Dubai Metro is a driverless, fully automated metro network in the United Arab Emirates city of Dubai. The Red Line and Green Line are operational, with three further lines are planned. These first two lines run underground in the city centre and on elevated viaducts elsewhere...

, Mecca Metro
Mecca Metro
The Mecca Metro, officially the Al Mashaaer Al Muqaddassah Metro, is an long elevated metro in the city of Mecca, Saudi Arabia, which opened in November 2010.-Background:...

, Los Teques Metro
Los Teques Metro
The Los Teques Metro is a suburban mass-transit system that is being built in the city of Los Teques, Venezuela with connections to important surrounding cities and communities. It was opened to public service on November 3, 2006....

, Tyne & Wear Metro, some of other Brazilian metros, MetroSur and other lines of Madrid Metro
Madrid Metro
The Madrid Metro is a metro system serving the city of Madrid, capital of Spain. The system is the sixth longest metro in the world though Madrid is approximately the fiftieth most populous metropolitan area in the world...

, Singapore MRT
Mass Rapid Transit (Singapore)
The Mass Rapid Transit or MRT is a rapid transit system that forms the backbone of the railway system in Singapore, spanning the entire city-state. The initial section of the MRT, between Yio Chu Kang Station and Toa Payoh Station, opened in 1987 establishing itself as the second-oldest metro...

, Taipei Metro, Kuala Lumpur
Kuala Lumpur
Kuala Lumpur is the capital and the second largest city in Malaysia by population. The city proper, making up an area of , has a population of 1.4 million as of 2010. Greater Kuala Lumpur, also known as the Klang Valley, is an urban agglomeration of 7.2 million...

's RapidKL Light Rail Transit etc.) the mainly urban rapid transit systems branch out to the nearest suburbs. Some cities have opted for a hybrid solution, with two tiers of rapid transit: an urban system (such as the Paris Métro
Paris Métro
The Paris Métro or Métropolitain is the rapid transit metro system in Paris, France. It has become a symbol of the city, noted for its density within the city limits and its uniform architecture influenced by Art Nouveau. The network's sixteen lines are mostly underground and run to 214 km ...

, Berlin U-Bahn
Berlin U-Bahn
The Berlin is a rapid transit railway in Berlin, the capital city of Germany, and is a major part of the public transport system of that city. Opened in 1902, the serves 173 stations spread across ten lines, with a total track length of , about 80% of which is underground...

, London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...

) and a suburban system with lower frequency (such as their counterparts RER
RER
The RER is a rapid transit system in France serving Paris and its suburbs. The RER is an integration of a modern city-centre underground rail and a pre-existing set of commuter rail lines. It has several connections with the Paris Métro within the city of Paris. Within the city, the RER...

, S-Bahn
Berlin S-Bahn
The Berlin S-Bahn is a rapid transit system in and around Berlin, the capital city of Germany. It consists of 15 lines and is integrated with the mostly underground U-Bahn to form the backbone of Berlin's rapid transport system...

, future Crossrail
Crossrail
Crossrail is a project to build a major new railway link under central London. The name refers to the first of two routes which are the responsibility of Crossrail Ltd. It is based on an entirely new east-west tunnel with a central section from to Liverpool Street station...

, respectively). The suburban systems run on their own tracks with high frequency, but are often quite similar to commuter rail, and are often operated by the national railways. In some cities the national railway runs through tunnels in the city center; sometimes commuter trains have direct transfer to the rapid transits, on the same or adjoining platforms. California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

's BART system functions as a hybrid of the two: in the suburbs, it functions like a commuter rail, with longer trains, longer intervals, and longer distance between stations; in downtown San Francisco, many lines join and intervals drop to normal subway levels, and stations become closer together. Also, some other urban or "near urban" rapid transit systems (GuangFo Metro Line 1, East Rail Line in Hong Kong, Guarenas
Guarenas
Guarenas is a city in Miranda, Venezuela. It was established in 1621 as Nuestra Señora de Copacabana de los Guarenas. On February 27, 1989, a morning protest in this city over the recent nationwide hike in bus fares, spread to Caracas, the capital of Venezuela, which resulted in several days of...

-Guatire
Guatire
Guatire is a city in Miranda, Venezuela. In 2006, its population has been estimated at 200,417. Today, Guatire has virtually merged with its neighbor, Guarenas....

 metro, Mumbai
Mumbai
Mumbai , formerly known as Bombay in English, is the capital of the Indian state of Maharashtra. It is the most populous city in India, and the fourth most populous city in the world, with a total metropolitan area population of approximately 20.5 million...

-Thane
Thane
Thane , is a city in Maharashtra, India, part of the Mumbai Metropolitan Region, northeastern suburb of Mumbai at the head of the Thane Creek. It is the administrative headquarters of Thane district. On 16 April 1853, G.I.P...

 rail, Chennai MRTS (not to be confused with Chennai rail
Chennai suburban railway
Chennai suburban railway is a commuter rail system in the Indian city of Chennai operated by the Southern Railway. Chennai has a complex railway network. The system uses electrical multiple units operating on alternating current drawn from over-head cables through the catenary system...

), Korail
Korail
Korea Railroad Corporation , promoted as Korail , is the national railroad operator in South Korea.Korail operates passenger and freight trains throughout South Korea...

 Bundang Line
Bundang Line
Bundang Line is a commuter subway line of Korail, the national railway of South Korea. The name 'Bundang Line' refers to the fact that the line was constructed for the commuters of Bundang ward in Seongnam. The line starts in southeastern Seoul, travels through northern Seongnam, and finally...

, Sin Bundang Line
Sin Bundang Line
The Sin Bundang Line or DX Line is a 17.3 km long, wide-area rail line. It connects to the Seoul Metropolitan Subway...

, Jungang Line
Jungang Line
The Jungang Line is a railway line connecting Cheongnyangni in Seoul to Gyeongju in South Korea, traversing central South Korea from the northwest to the southeast.-History:...

, Gyeongui Line
Gyeongui Line
The Gyeongui Line is one of the oldest railway lines in Korea. When opened in 1906 it linked Seoul in what is now South Korea to P'yŏngyang and Sinŭiju in what is now North Korea...

, and Gyeongchun Line
Gyeongchun Line
The Gyeongchun Line is a railway line connecting Seoul to Chuncheon in South Korea. The line is operated by Korail. The name of the line came from Gyeongseong and Chuncheon. The line was reconstructed in a new alignment in its entirety in the 2000s...

 in the Seoul Metropolitan Area, etc.) serves the bi- and multi- nucleous agglomeration
Agglomeration
In the study of human settlements, an urban agglomeration is an extended city or town area comprising the built-up area of a central place and any suburbs linked by continuous urban area. In France, INSEE the French Statistical Institute, translate it as "Unité urbaine" which means continuous...

s.


Costs, benefits, and impacts


More than 160 cities have built rapid transit systems, and about twenty-five have new systems under construction. The capital cost is high, as is risk of cost overrun and benefit shortfall. Public financing is normally required. Rapid transit is sometimes seen as an alternative to an extensive road transport
Road transport
Road transport or road transportation is transport on roads of passengers or goods. A hybrid of road transport and ship transport is the historic horse-drawn boat.-History:...

 system with many motorways; the rapid transit system allows higher capacity with less land use, less environmental impact, and a lower cost.

Elevated or underground systems in city centers allow the transport of people without occupying expensive land, and permit the city to develop compactly without physical barriers. Motorways often push down nearby residential land values, but proximity to a rapid transit station often triggers commercial and residential growth, with large office and housing blocks being constructed.

See also

  • Bus rapid transit
    Bus rapid transit
    Bus rapid transit is a term applied to a variety of public transportation systems using buses to provide faster, more efficient service than an ordinary bus line. Often this is achieved by making improvements to existing infrastructure, vehicles and scheduling...

  • Megaproject
    Megaproject
    A megaproject is an extremely large-scale investment project. Megaprojects are typically defined as costing more than US$1 billion and attracting a lot of public attention because of substantial impacts on communities, environment, and budgets. Megaprojects can also be defined as "initiatives that...

  • List of metro systems
  • Total rapid transit systems statistics by country
    Total rapid transit systems statistics by country
    This table is based on List of rapid transit systems. Countries can be sorted by total length of rapid transit systems, total number of stations and the year of opening of the earliest system....


External links