Urban rail transit
Urban rail transit is an all-encompassing term for various types of local rail
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...

 systems providing passenger service
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...

 within and around urban
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...

 or 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...

an areas. The set of urban rail systems can be roughly subdivided into the following categories, which sometimes overlap because some systems or lines have aspects of each.


A tram, streetcar or trolley system is a rail-based transit system that runs mainly or completely along streets, with relatively low capacity and frequent stops. Passengers usually board at street- or curb-level, although low-floor trams may allow level boarding. Longer-distance lines are called 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...

or radial railways. Few interurbans remain, most having been upgraded to commuter rail or abandoned .

The term "tram" is used most parts of the world. In North America, these systems are referred to as "streetcar" or "trolley" systems.

Light rail

A Light rail system is a rail-based transit system that has higher capacity and speed than a tram, but is not fully grade-separated like rapid transit. It emerged as an outgrowth of trams/streetcars. Light rail systems vary significantly in terms of speed and capacity. They range from slightly improved tram systems to systems that are essentially rapid transit with level crossings.

The term "light rail" is the most common term used, though German systems are called "Stadtbahn" (City Rail).

Rapid transit

A rapid transit, underground, subway, tube, elevated, or metro system is a railway—usually 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 of service, 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.

In most parts of the world these systems are known as a "metro" which is short for "metropolitan". The term "subway" is used in many American systems as well as in Glasgow
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...

 and Toronto
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...

. The system in London
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...

 uses the terms "underground" and "tube". Systems in Germany are called "U-Bahn", which stands for "Untergrundbahn" (underground way). Many systems in East and Southeast Asia such as Taipei and Singapore
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...

 are called MRT which stands for Mass Rapid Transit. Systems which are predominantly elevated may be referred to as "L" as in Chicago
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...

 or "Skytrain", as in Bangkok and Vancouver
SkyTrain (Vancouver)
SkyTrain is a light rapid transit system in Metro Vancouver, British Columbia, Canada. SkyTrain has of track and uses fully automated trains on grade-separated tracks, running mostly on elevated guideways, which helps SkyTrain to hold consistently high on-time reliability...

. Other less common names include "MTR" and "T-bane".


A Monorail is a metro
Rapid transit
A rapid transit, underground, subway, elevated railway, metro or metropolitan railway system is an electric passenger railway in an urban area with a high capacity and frequency, and grade separation from other traffic. Rapid transit systems are typically located either in underground tunnels or on...

 with a track consisting of a single rail, as opposed to the traditional track with two parallel rails
Rail tracks
The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, sleepers and ballast , plus the underlying subgrade...


Commuter Rail

A commuter rail or regional rail system operates on mainline trackage which may be shared with intercity rail and freight trains. Systems tend to operate at lower frequencies than rapid transit systems, but tend travel at higher speeds and cover longer distances. Though many European and East Asian commuter rail systems operate with frequencies and rolling stock similar to that of rapid transit, they do not qualify as such because they share tracks with intercity trains.


A Funicular is a cable-driven inclined railway that uses the weight of descending cars to help pull the ascending cars up the slope.

Classification Issues

Transit agencies' names for lines do not necessarily reflect their technical categorization. For example, Boston
Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...

's Green Line
Green Line (MBTA)
The Green Line is a streetcar system run by the Massachusetts Bay Transportation Authority in the Boston, Massachusetts area of the United States. It is the oldest line of Boston's subway, which is known locally as the 'T'. The Green Line runs underground downtown and on the surface in outlying...

 is referred to as a subway, despite having street-running portions. Conversely, the 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...

 in London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

, Green Line in Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...

 and some metro lines in China are referred to as "Light Rail" even though they qualify as rapid transit because they are fully grade-separated and provide a high frequency of service.

Many cities use names such as subway and elevated railway to describe their entire systems, even when they combine both methods of operation. Slightly less than half of 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...

's tracks, for example, are actually underground; New York City's
Transportation in New York City
The transportation system of New York City is a cooperation of complex systems of infrastructure. New York City, being the largest city in the United States, has a transportation system which includes the largest subway system in the world, measured by track mileage; the world's first mechanically...

 subway also combines elevated and subterranean stations, while 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...

 and Vancouver SkyTrain use tunnels to run through central areas.


A 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...

 shares many characteristics with light rail and trams, but does not run on rails. Trolleybus
A trolleybus is an electric bus that draws its electricity from overhead wires using spring-loaded trolley poles. Two wires and poles are required to complete the electrical circuit...

es are buses that are powered from overhead wires. Vehicles that can travel both on rails and on roads, have been tried experimentally, but are not in common use. The term 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...

 is used to refer to various methods of providing faster bus services and the systems which use it have similar characteristics to 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...

. Some cities experimenting with guided bus
Guided bus
Guided buses are buses steered for part or all of their route by external means, usually on a dedicated track. This track, which often parallels existing roads, excludes other traffic, permitting the maintenance of reliable schedules on heavily used corridors even during rush hours.Guidance systems...

 technologies, such as Nancy, have chosen to refer to them as 'trams on tyres' (rubber tyred trams) and given them tram-like appearances.

Economics of rail transit

It is true that public rail transit provides certain benefits for a community. Economists encourage people, in addition to observing benefits, to consider the costs of urban transit as well. They agree the goals of policymakers in this situation are not often met. Some American economists claim that, contrary to popular belief, rail transit has failed to improve the environment, serve the poor, or reduce highway congestion in the United States. Economists, however, are somewhat more optimistic about rail transit's impact on economic development. But as more suburbanization occurs, central business districts decline, and people acquire more wealth a successful rail transit system might become harder to achieve
in the future.

According to one analysis, nine out of ten urban rail projects experience cost overrun
Cost overrun
A cost overrun, also known as a cost increase or budget overrun, is an unexpected cost incurred in excess of a budgeted amount due to an under-estimation of the actual cost during budgeting...

. The average overrun was 45 percent, measured in constant prices from decision to build to project completion.

See also

  • List of rail transit systems in North America
  • List of rail transit systems in the United States
  • List of rail transit systems by type
  • Passenger rail terminology
    Passenger rail terminology
    Various terms are used for passenger rail lines and equipment-the usage of these terms differs substantially between areas:-Rapid transit:A rapid transit system is an electric railway characterized by high speed and rapid acceleration. It uses passenger railcars operating singly or in multiple unit...

Further reading

  • "Electric Railway Transportation," Annals of the American Academy of Political and Social Science Vol. 37, No. 1, Jan., 1911 pp1-202 online 17 articles by experts in 1911.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.