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 trains on fixed rails. It operates on separate rights-of-way from which all other vehicular and foot traffic are excluded. It uses sophisticated signaling systems, and high platform loading.
Originally, the term rapid transit was used in the 1800s to describe new forms of quick urban public transportation that had a right-of-way separated from street traffic. This set rapid transit apart from horsecars, trams, streetcars, omnibuses, and other forms of public transport.
Metro, short for metropolitan railway refers to an urban, electric rail transport system with high capacity and a high frequency of service. Metros are totally separated from other traffic. They operate in tunnels, on elevated structures, or at surface level but with physical separation from other traffic. Metropolitan railways are used for high capacity public transportation - they can operate in trains of up to 10 cars, carrying 1800 passengers or more. In different parts of the world metro systems are also known as the underground, subway, or tube. In Germany the terms U-Bahn and S-Bahn are used. Some metro systems run on rubber tires, but are based on the same fixed-guideway principles as steel wheel systems.
Subway used in a transit sense refers to either a rapid transit system or a light rail/streetcar system that goes underground. The term may refer only to the underground parts of the system, or to the full system.
Subway is most commonly used in the United States and the English-speaking parts of Canada, though the term is also used elsewhere, such as to describe the subway line in Glasgow, Scotland, and in translation of system names or descriptions in some Asian and Latin American cities.
Some lines described as subway use light rail equipment. Notably, Boston's Green Line and the Newark City Subway, each about half underground, originated from fully surface streetcar lines. Also, the Buffalo Metro Rail is referred to as "the subway", while it uses light rail equipment and operates in a pedestrian mall downtown for half of its route and underground for the remaining section. Sometimes the term is qualified, such as in Philadelphia, where trolleys operate in an actual subway for part of their route and on city streets for the remainder. This is locally styled subway-surface.
In some cities where subway is used, it refers to the entire system; in others, only to the portions that actually are underground. Naming practices often select one type of placement in a system where several are used; there are many subways with above-ground components, and on the other hand, the Vancouver SkyTrain and Chicago 'L' include underground sections.
Interestingly, when the Boston subway was originally built, the subway label was only used for sections into which streetcars (trams) operated, and the rapid transit sections were called tunnels. Also, in some countries, subway refers to systems built under roads (such as the Glasgow Subway or London's Metropolitan Line) and the informal term tube is used for the deep-underground tunnelled systems (such as London's Piccadilly Line) - in this usage, somewhat technical nowadays and not used much in London, underground is regardless the general term for both types of system.
Bus subways are uncommon but do exist, though in these cases the non-underground portions of route are not called subways. Seattle, Washington, has a bus subway downtown, in which light rail trains and diesel-electric hybrid buses operate in a shared tunnel, with overhead wires which power the light rail trains, and the hybrid buses running in electrical-only mode while traveling through the tunnel. Bus subways are sometimes built to provide an exclusive right-of-way for bus rapid transit lines, such as the MBTA Silver Line in Boston. These are usually called by the term bus rapid transit.
'Subway' outside the USA, and especially in Europe often refers to an underground pedestrian passageway linking large road interconnections that are often too difficult or dangerous to cross at ground level. In Canada, the term subway may be used in either sense.
Underground and Tube 
The usage of underground is very similar to that of subway, describing an underground train system.
In London the colloquial term tube now refers to the London Underground and is the most common word used for the underground system, and it is used by Transport for London the local government body responsible for most aspects of the transport system throughout Greater London. However, strictly speaking, it should only refer to those deep lines which run in bored circular tunnels as opposed to those constructed near to the surface by 'cut-and-cover' methods. The Glasgow metro system is known as the Glasgow Subway or colloquial as "the subway". The word Metro is not usually used in London or Glasgow to refer to those cities' metros, but it is used in and around Newcastle upon Tyne to refer to the Tyne and Wear Metro.
Paris, Rome, Madrid, Barcelona, Copenhagen, Helsinki, Warsaw, Saint Petersburg, Rotterdam and Moscow all have metro (from the word metropolitan) systems which are called metro in French, Italian, Spanish, Danish, Finnish, Polish, Dutch and Russian.
U-Bahn and S-Bahn 
The term metro is not usually used to describe metro systems in German-speaking areas (Germany, Austria and parts of Switzerland), instead using the term U-Bahn—a shortening of Untergrundbahn, meaning "underground railway"—and S-Bahn—an abbreviation for the German "Stadtschnellbahn" (fast city train). So for example in Berlin, the mostly underground system is known as the Berlin U-Bahn and it is integrated with the mostly above-ground system, known as the Berlin S-Bahn. BVG, the operators of the Berlin U-Bahn system, describe the U-Bahn as "the largest metro system in Germany" and the S-Bahn system as an "urban rail system".
The same applies also to the S-Bahn and U-Bahn in Copenhagen, Denmark, with the only exception that the word "Metro" is used instead of "U-Bahn" and "S-tog" instead of "S-Bahn". (The Danish word "S-tog" applies to the trains (tog), rather than the tracks as in Germany; "S-tog" means "S-train".) Otherwise, the S-Bahn of Berlin and the S-tog of Copenhagen are very similar with the exception of the size.
Hamburg S-Bahn fulfills all criteria for heavy rail inside the state and city of Hamburg, but some lines go beyond the state border into the state of Niedersachsen and there the S-Bahn runs with lower train frequency.
In Switzerland, where there is only one underground railway system in Lausanne, the term metro is generally used, due to the influence from the French language.
In Sweden, the metro of Stockholm is called "Tunnelbana" or "T-bana" which applies to the fact that the trains often runs in tunnels. The same applies to Norway and the "T-bane" of Oslo.
Elevated and Overhead 
Elevated is a shorthand for elevated railway, a railway built on supports over other rights of way, generally city streets. The term overhead tends to be used in Europe. The names of elevated railways are sometimes further abbreviate it to El or L. Some examples include:
- Chicago 'L' The best known elevated transit system in the United States.
- Vancouver SkyTrain An automated rapid transit system that is mostly elevated.
- New York City Subway A combination of the old IRT and BMT rapid transit systems that had built or leased numerous elevated lines throughout the entire city. New York "El's" are the oldest ones in the United States, dating from 1869. Today, the majority of "El" lines in New York are in Brooklyn, Queens, and The Bronx. Most "El's" in Manhattan were torn down in the 1940s and '50s, some replaced by subways.
- Liverpool Overhead Railway This was the United Kingdom's only true elevated railway, although the London and Greenwich Railway of 1836 was constructed on a 3.45 miles (5.55 km) brick viaduct for the greater part of its length.
- SEPTA's Market-Frankford Line is elevated except for the portion running through center city, and is sometimes referred to as the "El".
- The Manila LRT Yellow Line in Manila, Philippines, is an elevated railway, made operational in 1984 and the country's first urban rail transit since Manila tram service ended in 1944, during the Japanese occupation of the city.
At-grade urban rail transit 
Tram, streetcar, trolley 
The terms tram, streetcar and trolley refer to most forms of common carrier rail transit that run entirely or partly on streets, providing a local service and picking up and discharging passengers at any street corner, unless otherwise marked. While tram or tramway are widely used worldwide, the term used varies in different dialects of English, with streetcar and trolley most commonly used in North America (streetcar being more common in the eastern part of the continent and trolley in the western part), while tram predominates in Europe and elsewhere.
Tram is a British word derived from Low German traam, meaning the "beam (of a wheelbarrow)". The term "tram" was originally used in the coal mines of Scotland and Northern England for a coal cart running on rails, although some sources claim (inaccurately) that it was derived from the name of engineer Benjamin Outram.
Streetcar is an American word derived from "street" + "car", where "car" is used in the sense of a vehicle running on rails, i.e. railway car. The first American streetcars, introduced around 1830, were horsecars, and this type of streetcar became ubiquitous because very few of the streets in American cities were paved. Mechanical versions, pulled by cables, were introduced around 1870. Electric streetcars were introduced in the 1880s and soon replaced the horse-drawn streetcar in cities across the United States.
Trolley is an American word derived from the electric current pickup mechanism in early systems. The first successful electric streetcars in the United States used a system devised by Frank J. Sprague, in which a spring-loaded trolley pole pushed a small trolley wheel up against an overhead wire to collect electricity for the motors. Although not the first overhead collection system, it was far more reliable than its predecessors, and eventually became used by almost all streetcars. Some authorities believe that the vehicle became known as a trolley car because it reminded people (particularly on the West Coast) of a boat trolling for fish. Others believe it derived from a dialect word for a wheeled cart.
In the U.S. the word tram frequently refers to a tourist bus with the appearance of a heritage streetcar, cable car, or rubber-tired people-mover. They are frequently used for parking lot shuttles at theme parks and major events or transportation within theme parks. Trolley can sometimes carry similar meaning, as in the RiverCity Trolley in Minneapolis, Minnesota.
Historical systems 
Heritage streetcar (also known as heritage trolley or vintage trolley) is an American term for streetcar systems that use vehicles that were built before 1960, or modern replicas of such vehicles.
Cable car is an American word for a passenger rail vehicle attached to a moving cable located below the street surface and powered by engines or motors at a central location, not on board the vehicle. There are cable cars operating in numerous cities, such as San Francisco, California. and Wellington, New Zealand
In the Tennessee Williams play A Streetcar Named Desire, the term streetcar is used allegorically to refer to Blanche DuBois' promiscuousness and inability to form permanent relationships, as in the sarcastic phrase: "Men (or women) are like streetcars. There'll be another one along any minute." There was actually a streetcar line in New Orleans named Desire Street and simply signed Desire. It is mentioned in the book and an actual New Orleans streetcar with that signage is seen at the beginning of the Marlon Brando-Vivien Leigh film.
Light railway 
A light railway is a British English term referring to a railway built at lower costs and to lower standards than typical "heavy rail". These lighter standards allow lower costs of operation at the price of slower operating speeds and lower vehicle capacity. They were permitted under the Light Railways Act 1896 and intended to bring railways to rural areas. The London Docklands Light Railway, has more rapid transit style features than would be typical of light rail systems, but fits within the U.K. light railway definition.
Light rail 
A light rail transit (LRT) system is an urban rail transit system with a "light" passenger capacity compared to heavy rail and metro systems. Its operating characteristics are that it uses railcars, called light rail vehicles (LRVs), operating singly or in short multiple unit trains on fixed rails in a right-of-way that is not necessarily grade separated from other traffic for much of the way. Light rail vehicles are almost always electrically driven, with power usually being drawn from an overhead line rather than an electrified third rail.
The phrase light rail was coined in the 1970s during the re-emergence of streetcars/trams with more modern technology. It was devised in 1972 by the U.S. Urban Mass Transportation Administration (UMTA) to describe new streetcar transformations which were taking place, and was a translation of the German word stadtbahn. However, instead of the literal translation of city rail, the UMTA used light rail instead. In general, it refers to streetcar/tram systems with rapid transit-style features. It is named to distinguish it from heavy rail, which refers to rapid transit systems as well as heavier regional rail/intercity rail.
A few systems such as people movers and personal rapid transit could be considered as even "lighter", at least in terms of how many passengers are moved per vehicle and the speed at which they travel. Monorails are a separate technology.
Light rail systems can typically handle steeper inclines than heavy rail, and curves sharp enough to fit within street intersections. They are typically built in urban areas, providing frequent service with multiple-unit trains or single cars.
The most difficult distinction to draw is that between light rail and streetcar/tram systems. There is a significant amount of overlap between the technologies, and it is common to classify streetcars/trams as a subtype of light rail rather than as a distinct type of transportation. The two general versions are:
- The traditional type, where the tracks and trains run along the streets and share space with road traffic. Stops tend to be frequent, and little effort is made to set up special stations. Because space is shared, the tracks are usually visually unobtrusive.
- A more modern variation, where the trains tend to run along their own right-of-way and are often separated from road traffic. Stops are generally less frequent, and the passengers are often boarded from a platform. Tracks are highly visible, and in some cases significant effort is expended to keep traffic away through the use of special signaling, and even grade crossings with gate arms.
- At the highest degree of separation, it can be difficult or impossible to draw the line between light rail and rapid transit, as in the case of London's Docklands Light Railway, which would likely not be called light rail were it not for the contrast between it and the London Underground.
Many light rail systems — even fairly old ones — have a combination of the two, with both on-road and off-road sections. In some countries, only the latter is described as light rail. In those places, trams running on mixed right of way are not regarded as light rail, but considered distinctly as streetcars or trams. However, the requirement for saying that a rail line is "separated" can be quite minimal — sometimes just with concrete "buttons" to discourage automobile drivers from getting onto the tracks.
There is a significant difference in cost between these different classes of light rail transit. The traditional style is often less expensive by a factor of two or more. Despite the increased cost, the more modern variation (which can be considered as "heavier" than old streetcar systems, even though it's called light rail) is the dominant form of new urban rail transit in the United States. The Federal Transit Administration helps to fund many projects, but as of 2004, the rules to determine which projects will be funded are unfavorable toward the simpler streetcar systems (partly because the vehicles tend to be somewhat slower). Some places in the country have set about building the less expensive streetcar lines themselves or with only minimal federal support. Most of these lines have been "heritage" railways, using refurbished or replica streetcars harkening back to the first half of the 20th century. However, a few, such as the Portland Streetcar, use modern vehicles. There is a growing desire to push the Federal Transit Administration to help fund these startup lines as well.
Light rail is generally powered by electricity, usually by means of overhead wires, but sometimes by a live rail, also called third rail (a high voltage bar alongside the track), requiring safety measures and warnings to the public not to touch it. In some cases, particularly when initial funds are limited, diesel-powered versions have been used, but it is not a preferred option. Some systems, such as AirTrain JFK in New York City, are automatic, dispensing with the need for a driver; however, such systems are not what is generally thought of as light rail, crossing over into rapid transit. Automatic operation is more common in smaller people mover systems than in light rail systems, where the possibility of grade crossings and street running make driverless operation of the latter inappropriate.
In the U.S., interurban (German Überland(straßen)bahn) refers to a higher-speed streetcar (tram) line – i.e. electrical railcars or trains which run both between the cities or towns (often in rural environments) on their own right-of-way, and through the city streets as trams. In the U.S., some interurban railcars constructed in the period 1900-1930 ran at extremely high speed for its time. Several advanced innovations – like streamlining, wind tunnel research and lightweight constructions – have their origin on the interurban scene, or were early adopted by companies like J. G. Brill Company, Cincinnati Car Company, and St. Louis Car Company. The fastest interurbans had a maximum service speed at 145–150 km/h, and an average speed including stops at above 80 km/h. The Cincinnati–Toledo route of Cincinnati and Lake Erie Railroad was 349 km (217 mi). A few interurbans like Philadelphia and Western Railroad adapted to high speeds with double-track, absolute block signalling and without grade crossings. Others ran at (too) high speed on single-track right-of-way without block signalling – and experienced disastrous wrecks.
The U.S. interurbans are all but gone, with two of the remaining (Norristown High Speed Line, IRT Dyre Avenue Line) having been upgraded to rapid transit specifications. The South Shore Line, which runs from Chicago's Millennium Station to South Bend, Indiana, has been converted to modern electric rapid-transit operation on the dense corridor between Chicago and Gary, Indiana but still runs essentially as an interurban through several small towns between Gary and South Bend.
The European interurbans, like the Silesian Interurbans (Tramwaje Śląskie S.A.; German Schlesische Straßenbahn) and Belgium’s Kusttram, were (and are) more like conventional tramways, as their names indicate.
Interurbans sometimes used freight railways rather than building their own track.
In Australia, interurban refers to long distance commuter trains such as the routes between Newcastle and Sydney, between Brisbane and Gympie, or between Brisbane and the Gold Coast. Some interurban trains may operate from where suburban lines end, such as Southern Higlands services between Campbelltown and Goulburn, or between Ipswich and Rosewood. These do not have the features of "intercity trains" in other parts of the world, such as booked seats and meal services, but are bare commuter trains. They are properly called interurban rather than intercity, although CityRail refers to its interurban services as "intercity" trains.
Tram-trains are railcars or trains which run like trams (streetcars) in city streets, and on heavy rail tracks out to the suburbs or between the cities. Usually, this requires two current systems (German Zweisystemstadtbahn, Stadtbahn with two systems), both the tram voltage (600 or 750 V DC) and the heavy rail high voltage (in Germany, 15 kV AC). The vehicles must also be adapted to the heavy rail’s signalling system. This transit mode combines the tram’s availability with stops in the street, and the heavy rail’s higher speed. They are often faster than most rapid transit (metro) systems. The first system was opened in Karlsruhe in 1992. Their top speed is often 100 km/h, in Kassel as much as 114 km/h. Most of the tram-trains fit the definition of an interurban; in reality, this transit mode is a rebirth of the interurban.
Heavy rail 
A heavy rail system is an electric railway with the capacity to handle a heavy volume of traffic. The term is often used to distinguish it from light rail systems, which usually handle a smaller volume of passengers.
In Britain, heavy rail refers to regional rail, international rail (Eurostar) and intercity rail services as distinct from other rapid transit or light rail modes, such as when referring to National Rail services in London.
In North America, heavy rail can also refer to rapid transit, when referring to systems with heavier passenger loadings than light rail systems, but distinct from commuter rail and intercity rail systems. It is characterized by high-speed, passenger rail cars running in separate rights-of-way from which all other vehicular and foot traffic are excluded.
Regional rail and Commuter rail 
Regional rail (also called metropolitan rail, commuter rail, or suburban rail) is an electric or diesel propelled railway for urban passenger train service consisting of local short distance travel operating between adjacent cities and towns, or between a central city and adjacent suburbs, using either locomotive hauled or multiple unit railroad passenger cars.
Regional rail usually provides rail services between towns and cities, rather than purely linking major population hubs in the way inter-city rail does. Regional rail operates outside major cities. Unlike Inter-city, it stops at most or all stations. It provides a service between smaller communities along the line, and also connections with long-distance services. Alternative names are "local train" or "stopping train". Examples include the former BR's Regional Railways, France's TER (Transport express régional) and Germany's DB Regio services. Regional rail operates throughout the day but often at low frequency (once per hour or only a few times a day), whereas commuter rail provides a high-frequency service within a conurbation.
Regional rail in this sense does not exist in North America, where the term "regional rail" is synonymous with commuter rail.
Regional trains are usually all seated and provide luggage space, although they seldom have all the amenities of inter-city trains such as a buffet or dining car. Since their invention, the distinction between regional and long-distance rail has also been the use of multiple unit propulsion, with longer distance trains being locomotive hauled, although development of trains such as the British Rail Class 390 have blurred this distinction. Shorter regional rail services will still usually be operated exclusively by multiple units where they exist, which have a shorter range and operate at lower average speeds than services on Inter-city rail networks. Not using a locomotive also provides greater passenger capacity in the commuter role at peak periods.
British Rail, during sectorisation, did once create a "Regional Railways" subsidiary, however this was so named to differentiate it's 'all other regions' lines from the other sectors Network SouthEast, which heavily focused on commuters services to London terminal stations but operated rail services across the South East region, and the Inter-City sector which operated long distance services.
Commuter rail in North America refers to urban passenger train service for local short-distance travel operating between a central city and its suburbs. Such rail service, using either locomotive-hauled or self-propelled railroad passenger cars, is characterized by multi-trip tickets, specific station-to-station fares, and usually only one or two stations in the central business district. It does not include heavy rail, rapid transit, light rail, streetcar, tram, or intercity rail service.
Intercity, Corridor and Long-Distance 
The Inter-City was a British named train, introduced in 1950, but the term InterCity was adopted by British Rail in 1966 as a brand-name for its long-haul express passenger services. Since then, the terms Inter-city or intercity have been widely adopted to refer to express passenger train services that cover longer distances than commuter or regional trains.
In the US, "Corridor" services refer to routes connecting relatively nearby cities, where one city can be visited from another without staying overnight. "Long-Distance" refers to routes which cover vast rural distances.
Other types of rail transit 
Automated guideway transit refers to guided transit vehicles operating singly or in multi-car trains with fully automated control (no crew on transit units). Service may be on a fixed schedule or in response to a passenger-activated call button. Automated guideway transit includes personal rapid transit, group rapid transit and people mover systems.
Personal rapid transit (PRT), also called personal automated transport (PAT), is a public transportation concept that offers on-demand, non-stop transportation, using small, independent vehicles on a network of specially built guideways.
People mover or automated people mover (APM) systems are fully automated, grade-separated mass transit systems which serve a relatively small area such as an airport, downtown district or theme park. The term "people mover" has become generic for the type of system, which may use technologies such as monorail, duorail, automated guideway transit or maglev.
Monorail means a system of guided transit vehicles operating on or suspended from a single rail, beam, or tube. Usually they operate in trains. Monorails are distinguished from other types of elevated rail system by their use of only a single beam, and from light rail and tram systems by the fact they are always grade separated from other vehicles and pedestrians.
Suspension railway is a form of elevated monorail where the vehicle is suspended from a fixed track (as opposed to a cable used in aerial tramways), which is built above street level, over a river or canal, or an existing railway track.
Service type 
Local service 
Means trains stop at every station on a route. For light rail vehicles operating on city streets, local service is analogous to local bus service, where stops are every block or two apart.
Regional service 
Regional passenger trains may be classified as either slow or stopping trains, or else limited-stop or semi-fast trains, where not all stations and stops are served. For example a pair of closely spaced trains may both stop at the most heavily used stations. For lesser-used stations, the first train stops at alternate stations, while the following train stops at the stations missed by the first train. or else express trains.
Express service 
Means trains operate for long distances without stopping, skipping some stations between stops. This speeds up longer trips, especially in major urban areas. In major cities, express trains may have separate tracks for at least part of their routes.
Passenger boarding 
Street-level boarding 
Used primarily by light rail and tram lines that stop on the street rather than at stations. No platforms are used, the passengers walk up steps into the vehicles. For wheelchairs, a retractable lift or ramp is required to gain access to the vehicle.
Low-level platforms 
Generally about 30 to 45 centimetres (12 to 18 in) above track level and are used primarily by some commuter rail and light rail lines. Wheelchairs can board low-floor vehicles directly from the platform, but high-floor vehicles require retractable lift or ramp.
High-level platforms 
Generally 45 to 95 centimetres (18 to 37 in) above track level and are used primarily by heavy rail, automated guideway, and some commuter rail lines. Only high-floor vehicles can be used, but wheelchairs can board directly from platforms if vehicle floors are level with the platform.
Rail terminology with regard to speed 
Non-high-speed rail: Less than 200 km/h 
The vast majority of local, regional and express passenger trains, and almost 100% of freight trains are of this category.
High-speed rail: 200 km/h – 400 km/h 
There is no globally accepted standard separating high-speed rail from conventional railroads; however a number of widely accepted variables have been acknowledged by the industry in recent years. Generally, high-speed rail is defined as having a top speed in regular use of over 200 km/h (124 mph). Although almost every form of high-speed rail is electrically driven via overhead lines, this is not necessarily a defining aspect and other forms of propulsion, such as diesel locomotives, may be used. A definitive aspect is the use of continuous welded rail which reduces track vibrations and discrepancies between rail segments enough to allow trains to pass at speeds in excess of 200 km/h (124 mph). Track radius will often be the ultimate limiting factor in a train's speed, with passenger discomfort often more imminent than the danger of derailment. Depending on design speed, banking and the forces deemed acceptable to the passengers, curves often exceed a 5 kilometer radius. Tilting trains have been developed for achieving greater comfort for passengers, so higher speeds are possible on curvy tracks. Although a few exceptions exist, zero grade crossings is a policy adopted almost worldwide, with advanced switches utilizing very low entry and frog angles. Magnetic levitation trains fall under the category of high-speed rail due to their association with track oriented vehicles; however their inability to operate on conventional railroads often leads to their classification in a separate category.
In the US, "high speed rail" is often used to describe services faster than 100 mph (160 km/h). This is because few regular services in the US exceed 80 mph (130 km/h) (with the exception of Acela Express), which is low by international standards.
Very high-speed rail: 310 km/h – 500 km/h 
Very high-speed rail is a term used for the fastest trains introduced after 2000, exceeding 300 km/h.
It is planned that 350 km/h will be reached in short future with regular trains, and possibly 400 km/h on long term.
Ultra high-speed rail: 500 km/h – 1000 km/h 
A number of both technological and practical variables begin to influence trains in the vicinity of 500–600 km/h. Technologically the limitations are by no means beyond reach, however conventional trains begin to encounter several physical obstacles, most notably track damage and pantograph limitations. It is important to note that the current world record for rail vehicles is held by the TGV V150 set on 15 April 2007 at 574.8 km/h, and conventional trains may indeed eventually reach into very high-speeds. However, this test has shown that speeds over 500 km/h are unrealistic for regular usage; it wears down the material too much. Based on current and foreseeable technology, these speeds will more than likely be reached predominantly by maglev trains. The two most prominent maglev trains are the Transrapid with a maximum speed of 550 km/h; and the JR-Maglev MLX01, which holds the world land speed record for railed vehicles at 581 km/h.
Trains faster than 600 km/h will exceed the speed of most propeller-driven aircraft. Regardless of technological parameters, the track for such a train and anything faster would more than likely require turn radii of significantly higher proportions than current dimensions, essentially preventing anything but a direct line between terminals. Such trains are extremely unlikely in the current or near future.
Greater than 1000 km/h 
Depending on the aerodynamic design of the vehicle and various ambient atmospheric conditions, a train would begin to exhibit transonic airflow in the vicinity of Mach 0.8 (988 km/h) and higher. From a modern perspective, this is essentially the realistic maximum speed of trains as they are known today. This is because the Prandtl-Glauert singularity would cause catastrophic damage to the vehicle as the sound waves reflected off of the ground, potentially blasting the train into the air. The only trains that could exceed this speed significantly are vactrains.
Rail terminology with respect to rail gauge 
Approximately 60% of the world's existing railway lines are built to the standard rail gauge where the distance between the inside edges of the rails of the track is 1,435 mm (4 ft 8 1⁄2 in) (see the list of countries that use the standard gauge).
Narrow gauge railways have rail gauges of between 2 ft (610 mm) and 3 ft 6 in (1,067 mm). They are cheaper to build and operate, but tend to be slower and have less capacity. Minimum gauge railway have a gauge of less than 2 ft (610 mm) or 600 mm (1 ft 11 5⁄8 in) and are primarily used as industrial railways rather than for passenger transit. However many miniature railways use this type of gauge. Broad gauge railways use a rail gauge greater than 1,435 mm (4 ft 8 1⁄2 in).
Comparison of types 
|Rail tracks||At grade||Mixed - mostly
|Grade separated||Grade separated|
|Power supply||Overhead lines||Overhead lines||Third rail
|Units per train||1-2||2-6||Up to 10||Up to 12|
|Average speed (km/h)||10-20||30-40||30-40||45-65|
|Passengers per train||125-250||260-900||800-2,000||1,000-2,200|
per hour per direction
||This article needs additional citations for verification. (June 2007)|
- "Rail Definitions". American Public Transportation Association. 2003. Archived from the original on 2009-06-11. Retrieved May 26, 2012.
- "What are metros?". UITP - International Association of Public Transport. 2009. Retrieved 2009-09-16.
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- Bruce, J. Graeme (1979). Tube trains under London. London: London Transport. pp. Foreword. ISBN 0-85329-095-4.
- Transports Metro
- MetroRoma - Home
- Metro de Madrid
- The Berlin metro (U-Bahn)
- The urban rail system (S-Bahn)
- Post, Robert C. (2007). Urban Mass Transit - The Life Story of a Technology. Greenwood Press. ISBN 0-313-33916-3.
- Wellington Cable Car
- Thompson, Gregory L. (2003). "Defining an Alternative Future: Birth of the Light Rail Movement in North America" (PDF). US Transportation Research Board. Retrieved 2009-01-09.
- American Public Transport Association definition of heavy rail
- "Transit Glossary". US Federal Transit Administration. 2008. Retrieved 2009-01-12.
- Cervero, Robert (1998). The Transit Metropolis - A Global Inquiry. Island Press. ISBN [[Special:BookSources/1-55963-593-6|1-55963-593-6 [[Category:Articles with invalid ISBNs]]]] Check
See also