Science Fair Project Encyclopedia
- This article talks about urban rail systems with certain characteristics, usually running at least partially on the surface with frequent stops and relatively low capacity. For a treatment of transit in cities in general, including terminology, see urban rail transit. For systems built to higher standards, usually with fuller grade separation and higher capacity, see urban heavy rail (despite some of these having light rail in their name).
- For specific light rail systems, many of which use the words light rail as part of their name, see list of light rail transit systems.
Light rail (streetcar, tram, trolley) is a type of railroad, typically in an urban area. Light rail systems are typically smaller scale than urban heavy rail, running partially or fully on the surface.
Light rail systems are almost universally operated by electricity delivered through overhead lines, although several systems are powered through different means, such as trams in Bordeaux which use a special third-rail configuration in which the rail is only powered while a tram is on top of it (making it safe to install third rails even on city streets). A few unusual systems such as the River LINE in New Jersey and the O-Train in Ottawa even use diesel-powered trains, though this is sometimes intended as an interim measure until the funds to install electric power become available.
As with other rail systems, the rail gauge has had considerable variations, but today standard gauge is dominant. Narrow gauge was common in many earlier systems, although as systems merged or died out, old lines were often upgraded, removed, or replaced. Some systems still use other track gauges, however.
Tram systems are common throughout Europe and were common throughout the Western world in the early 20th century. Although they disappeared from many cities for many years in the mid 20th century, in recent years they have made a comeback.
From the mid-19th century onwards, horse-drawn trams (or horsecars) were used in many cities around the world. The first trams, known as streetcars, or horsecars, were built in the US; they circulated in Baltimore, Maryland in 1828, in 1832 on the New York and Harlem Railroad in New York City and in 1834 in New Orleans. These streetcars were an animal railway usually using horses and sometimes mules to haul the cars, usually two as a team. Rarely other animals were tried, including humans in emergency circumstances.
The horsecars were necessary but had problems. One of the best advantages over earlier forms of transit was the low rolling resistance of metal wheels on steel rails, allowing the animals to haul a greater load for a given effort. Problems included the fact that any given animal could only work so many hours on a given day, had to be housed, groomed, fed and cared for day-in and day-out, and produced prodigious amounts of manure which the streetcar company was charged with storing and then disposing of. Since a typical horse pulled a car for perhaps a dozen miles a day and worked for four or five hours, many system needed ten or more horses in stable for each horsecar. New York City had the last regular horsecar lines in the U.S., closing in 1914. A mule-powered line in Celaya, Mexico operated until 1956.
At first the rails, protruding above street level, caused major trouble for pedestrians and caused accidents. They were supplanted in 1852 by grooved rails, invented by Alphonse Loubat. The first tram in France was inaugurated in 1853 for the World's Fair, where a test line was presented along the Cours de la Reine , in the 8th Arrondissement .
The tram developed after that in numerous cities of Europe (London, Berlin, Paris, etc.). More rapid and comfortable than the omnibus, trams had a higher cost of operation because they were pulled by horses. That's why mechanical drives were rapidly developed: with steam power in 1873, and electrical after 1881, when Siemens presented the electric drive at the International Electricity Exhibition in Paris.
The technical modernity of electricity and more importantly its convenience resulted in its rapid adoption, once the technical problems of production and transmission of electricity were solved. The first electric tram opened in Berlin in 1881.
In the late 1880s electrically-powered street railways became technically feasible following the invention of a trolley system of collecting current by American inventor Frank J. Sprague who installed the first successful system at Richmond, Virginia. They became popular because roads were then poorly surfaced, and before the invention of the internal combustion engine and the advent of motor-buses, they were the only practical means of public transport around cities.
The light rail systems constructed in the 19th and early 20th centuries typically only ran in single-car setups. Some rail lines experimented with multiple unit configurations, where streetcars were joined together to make short trains, but this didn't become common until later. When lines were build over longer distances (typically with a single track) before good roads were common, they were generally called interurbans in North America or radial railways in Ontario.
Trams experienced a rapid expansion at the start of the 20th century until the period between the two world wars. There was a rapid increase in the number of lines and increase in the number of riders: indeed, it became the primary mode of urban transportation. Horse-drawn transport virtually disappeared in all of the European and American cities by 1910. Buses were still in a development phase at this time, gaining in mechanical reliability, but remaining behind compared to the benefits offered by trams; the automobile was still - for a time - reserved for the well-to-do.
A temporary disappearance from many cities
In several countries the advent of personal motor vehicles caused the rapid disappearance of the tram from the urban landscape in the 1950s. The technical progress of the bus rendered it more reliable, and it became a serious competitor to the tram because it didn't require the construction of costly infrastructure.
Governments thus invested mostly into bus networks. Indeed, infrastructure for roads and highways meant for the automobile were perceived as a mark of progress. The priority given to roads is illustrated in the proposal of French president Georges Pompidou who declared in 1971 that "the city must adapt to the car".
Tram networks were no longer maintained or modernized, a state of affairs that served to discredit them in the eyes of the public. Old lines, considered archaic, were then bit by bit replaced by buses.
Tram networks disappeared almost completely from North America, France, the UK, and Spain and Mumbai. On the other hand, they were maintained or modernized in Switzerland, Germany, Poland, Finland, Romania, Austria, Italy, Belgium, the Netherlands, Scandinavia, Japan, and Eastern Europe. In France and the UK, only the networks in Lille, Saint-Etienne, Marseille, and Blackpool survive from this period, but they are each reduced to a single line. Australian tram networks disappeared by the 1970's, with the exception of the extensive system in Melbourne and one tram line in Adelaide.
In North America, many of these original light-rail systems were decommissioned in the 1950s and onward as the popularity of the automobile increased. Although some traditional trolley or tram systems still exist to this day, the term "light rail" has come to mean a different type of rail system. Beginning in the 1980s, some cities began reintroducing light-rail systems that are more like subway or metro systems that operate at street level. These light-rail systems include modern, multi-car trains that can only be accessed at stations that are spaced anywhere from a couple blocks to a mile or more apart. Some of these systems operate within roadways alongside automobile traffic, and others operate on their own separate right-of-way.
In Canada, most cities once had a streetcar system, but today Toronto's TTC is the only operator of streetcars in that country, and maintains the most extensive system in North America (in terms of total track length, number of cars, and ridership).
Most US streetcar systems were removed by the 1950s. Among the reasons, the US firm of General Motors formed a separate subsidiary named "National City Lines", whose business mission was to buy out streetcar operations all around the US and replace them with fleets of buses.
Return to grace
The priority given to personal vehicles and notably to the automobile led to a loss in quality of life, particularly in large cities where smog, sound pollution and parking became problematic. Acknowledging this, some authorities saw fit to redefine their transport policies. The bus had shown its limits on account of its low capacity and its difficult coexistence with automobile traffic, which made it slow both on the road and commercially. Subways required a heavy investment and presented problems in terms of subterranean spaces that required constant security. For subways, the investment was mainly in underground construction, which made it impossible in some cities (with underground water reserves, archaeological remains, etc.). Subway construction thus was not a universal panacea.
The advantages of the tram thus became more visible. At the end of the 1970s, some governments studied, and then built new tram lines. In France, Nantes and Grenoble lead the way in terms of the modern tram, and new lines were inaugurated in 1985 and 1988. Strasbourg moved forward as well when it opened in 1994 a line with distinctly novel train designs, specified by the city, with the goal of breaking with the archaic conceptual image that was held by the public.
The public, who realized with each installation of tram lines their benefits in urban flexibility and redistribution, or else the reduction in automobile traffic in the downtown, encouraged numerous city governments to so equip their streets. The cities already equipped with trams do not hesitate to extend their lines, indeed even making new ones.
A great example of this shift in ideology is the city of Munich, which began replacing its tram network with metro a few years before the 1972 summer Olympics . When the complete metro network had been finished in the 1990s, the city began to tear out the tram networks (which had become rather old and decrepit), but now faced opposition from many citizens who enjoyed the enhanced mobility of the mixed network (the tram lines deviate from the metro lines to a significant degree). New rolling stock was purchased and the system was modernized, and a new line was proposed in 2003.
Not all streetcars systems were removed; the San Francisco cable cars are the most famous example in the United States. More conventional streetcar operations survived complete abandonment in Boston, Cleveland, Newark, New Orleans, Philadelphia, Pittsburgh, and San Francisco in the United States, together with Toronto in Canada. All of these systems have received new equipment. Some of these cities have also rehabilitated lines, and Newark, New Orleans, and San Francisco have added trackage in recent years. In Toronto, the city has added 2 new lines in recent years, and is activly upgrading its other lines. Further expansion is planned in combination with the city's plans for the rejuvenation of its waterfront.
More recently a number of American cities have built new light rail systems which operate partially in the right-of-way of city streets. These systems could be called trams by Europeans and Australians but are generally not known by that name within the US, where the term light rail is generally applied. San Diego, California was the location of one of the earlier of these new systems, which substantially utilized European technology.
Heritage Streetcar Systems
Heritage streetcar systems are used in public transit service, combining light rail efficiency with America's nostalgia interests. Proponents claim that using a simple, reliable form of transit from 50 or 100 years ago can bring history to life for 21st century Americans. Systems are operating successfully in over 20 U.S. cities,and are in planning or construction stages in 40 more. Heritage systems currently operating in Memphis, Tennessee, Tampa, Florida and New Orleans, Louisiana are among the larger.
Over 50 years after the Tennessee Williams play A Streetcar Named Desire opened on Broadway, the revival of streetcar operations in New Orleans is credited by many to the worldwide fame gained by the streetcars made by the Perley A. Thomas Car Works. These cars were operating on the system's Desire route in the 1947 play and later movie of the same name. Some of the original cars have been carefully restored locally and continue to operate in 2004.
Later trams, known as cable cars, attached to a moving cable underneath the road. The cable would be pulled by a steam engine at a powerhouse. The Monongahela and Duquesne Inclines in Pittsburgh, Pennsylvania, USA, have some of the appearance of trams, but are more accurately funiculars. Modern trams generally use overhead electric cables, from which they draw current through a pantograph, a bow collector (less commonly) or a trolley pole (the first is most common and used on most new tram designs). The first operational electric street railway was started in Scranton, Pennsylvania, but the first large-scale electric street railway system was built in Richmond, Virginia in January, 1888. By 1890 over a hundred such systems had been begun or were planned.
There are other methods of powering electric trams, sometimes preferred for aesthetic reasons since poles are not required. The old tram systems in London, Manhattan (New York City) and Washington D.C. - the latter two called conduit cars - used live rails, like those on third rail electrified railways, but underneath the road from which they drew power through a plough. Washington was the last to close, in 1962. Today, no commercial tramway uses this system, as electrocution of children and animals is a serious problem, as well as current leak. There also have been street compatible third rail current collection systems, known as surface current collection, more recently as ground level power supply.
Double track tram lines are sometimes at narrow passages single track, or, to avoid switches, have the tracks interlaced, e.g. in the Leidsestraat in Amsterdam on three short stretches (see map detail); this is known as a gauntlet track setup.
Since the 1990s, low floor trams, allowing passengers in wheelchairs or with perambulators to access vehicles more easily, have begun to replace traditional trams where you needed to climb some steps to reach the passenger cabin.
Complementary to the traditional tram, these evolutions make it possible to cover more space or to cross slopes inaccessible to the traditional tram.
Main article: Cable car (railway)
The next type of streetcar, after the horsecar, was the cable car, which sought to reduce labor costs and the hardship on animals. Cable cars are pulled along a rail track by a continuously moving cable running at a constant speed and on which individual cars stop and start by releasing and gripping this cable as required. The power to move the cable is provided at a site away from the actual operation. The first cable car line in the United States was tested in San Francisco, California in 1873.
Cable cars suffered from high infrastructure costs, since a vast and expensive system of cables, pulleys, stationary engines and vault structures between the rails had to be provided. They also require strength and skill to operate, to avoid obstructions and other cable cars. The cable had to be dropped at particular locations and the cars coast, for example when crossing another cable line. After the development of electrically-powered streetcars, the more costly cable car systems declined rapidly.
Cable cars were especially useful in hilly cities, partially explaining their survival in San Francisco, though ironically the most extensive cable system in the U.S. was in Chicago, Illinois, a flat city. The San Francisco cable cars continue to perform a regular transportation function, in addition to being a tourist attraction.
Trolley cars, so called for the trolley pole used to gather power from an unshielded overhead wire or cable, were first successfully tested in actual service in Richmond, Virginia in 1888, in an installation by Frank J. Sprague. There were earlier commercial installations of electric streetcars, including one in Berlin, Germany, as early as 1881 by Werner Siemens and the company that still bears his name. The earlier installations, however, proved difficult and/or unreliable. Siemen's line, for example, provided power through a live rail and a return rail, like a model train setup, limiting the voltage that could be used, and providing unwanted excitement to people and animals crossing the tracks.
Since Sprague's installation was the first to prove successful in all conditions, he is credited as being the inventor of the trolley car.
Trolley car systems in the U.S. and Canada became quite extensive, but, hit by the Great Depression, automobile competition, hostile politicians and predatory practices, declined precipitously after World War II. Some systems never closed however, with lines surviving in several cities even at the trolley's nadir in North America.
Concern about automobile traffic, fossil fuel availability, pollution and quality-of-life issues began a trend back to urban electric rail travel in North America during the 1970s, and a significant number of new lines and extensions and upgrading of other lines has occurred.
The tram-train uses a system which makes it possible to circulate on tramcar lanes in the downtown area, while circulating on the regional rail network. It requires components compatible with the traditional railroad (indication, power, resistance).
This system should be brought into service in the Paris area in 2005.
Advantages of light rail
Light rail systems are generally cheaper to build than heavy rail, since the infrastructure does not need to be as substantial, and tunnels are generally not required as is the case with most metro systems. Moreover, the ability to handle sharp curves and steep gradients can reduce the amount of work required.
Traditional streetcar systems as well as newer light rail systems are used in many cities around the world because they typically can carry a larger number of people than any bus-based public transport system. They are also cleaner, quieter, more comfortable, and in many cases faster than buses. In an emergency, light rail trains are easier to evacuate than monorail or elevated rapid rail trains.
Many modern light rail projects re-use parts of old rail networks, such as abandoned industrial rail lines.
A good example of both points above is the Docklands Light Railway (DLR) in London, which uses a sharp, steep, curve to enable it to transfer from running alongside an existing railway line to a disused railway line which crossed underneath the first line. A direct connection between these lines would not be practical for conventional rail (note that because the DLR has a completely grade-separated right of way, it can also be regarded as a metro).
Disadvantages of light rail
Like all modes of rail transport, light rail tends to be safest when operating in dedicated right-of-way with complete grade separations. However, grade separations are not always financially or physically feasible.
In California, the development of light rail systems in Los Angeles and San Jose led to a high rate of collisions between automobiles and trolleys during the 1990s. The most common cause was that many senior citizens were unfamiliar with light rail trolleys and often mistook the trolley "T" signal lights for left-turn signal lights. They would then make a left turn, right into the path of a trolley. The same high crash rate problem existed when the METRORail was first established in Houston, Texas.
To reduce such collisions, brighter lights and louder warning klaxons have been added to many at-grade crossings. However, as a result, many people do not like to live next to light rail crossings because the noise makes it impossible to sleep.
Monorail advocates like to point out that light rail trolleys are heavier per pound of cargo carried than heavy rail cars or monorail cars, because they must be designed to survive collisions with automobiles.
In the Netherlands many local railways were referred to as Trams, even where the steam locomotives did not have enclosed motion. In Belgium an extensive system of tram-like local railways called Vicinal or Buurtspoor lines had a greater route kilometre length than the actual railway system. The only survivors of the Vicinal system are the Kusttram (which almost reaches France at one end and the Netherlands at the other) and two lines near Charleroi.
In the United Kingdom, tram systems were widely dismantled in the 1950s, and after the closure of Glasgow's extensive network in 1962, only Blackpool's survived (see Blackpool Tram Upgrade ), although a funicular line continued to operate up the Great Orme in Llandudno. However in recent years new light rail lines have been opened in Manchester (Metrolink), Sheffield (Supertram), the West Midlands (Midland Metro), Croydon (Tramlink) and Nottingham (NET), with several others under consideration, and extensions planned for many existing systems.
All countries of the former Soviet Bloc have extensive tram infrastructure. Industrial freight use of city tram lines was a widespread practice during the communist era but has since mostly disappeared, as factories left the urban areas. Czech Tatra and the Hungarian Ganz factory were notable manufacturers of tram carts in Eastern Europe. The busiest traditional city tram line in the world is still Route 4/6 in Budapest, Hungary, where 50-meter long trains run at 60 to 90 second intervals at peak time and are usually fully packed with people. A part of this route is the same where electric trams made their world-first run in 1887. Most vehicles still belong to the high floor level type, in fact many of them ancient ones. Low floor, hi-tech trams are only starting to infiltrate Eastern European lines due to their extreme pricetag and high maintenance costs.
Whilst many North American cities abandoned their streetcar systems in the mid-twentieth century, traditional systems survived in Boston, Cleveland, Newark, New Orleans, Philadelphia, Pittsburgh, San Francisco, and Toronto. This survival was aided by the introduction of the modern PCC car in the 1940s and 1950s in all these cities except New Orleans.
New light rail systems have since opened in many other cities, starting with the ground breaking system in San Diego, and now including Baltimore, Hoboken, Buffalo, Denver, Los Angeles, Portland, Sacramento, St Louis, Salt Lake City, and San Jose. Additionally, all the surviving PCC operators have replaced their PCC cars with light rail vehicles, although PCC cars are still in regular operation on San Francisco's F Market line.
Another trend originating in North America is the introduction of newly built heritage streetcar lines using original or replica historic equipment, a trend which is now spreading elsewhere in the world. Examples in North America include Memphis, Tampa and the new Canal Street line in New Orleans.
See also: Streetcars in North America
Asia has had relatively few tram systems, with the notable exception of Japan.
Outside Japan, Hong Kong still possesses the Hong Kong Tramway, a traditional English-style double-decker tramway, with street running along the north shore of Hong Kong Island. More recently the KCRC Light Rail system has opened in the north west New Territories. Despite its name, the Peak Tram is actually a funicular railway with no tramway connections.
In Melbourne, in addition to newer types of trams in use such as the Citadis and the Combino as well as middle-aged A, B and Z class trams, older W-class trams remain in service and are a popular tourist attraction. Older W-class trams are used exclusively on the free City Circle tram route, but are also in use on some regular routes. A total of 53 W-class trams remain in regular service, with the oldest in service tram dating from 1939. See also: Trams in Melbourne.
Amongst other Australian cities, Sydney closed a once-extensive tram system in the 1950s but has since opened a new light rail line. Adelaide also closed its urban tram network, but has retained an express tram line linking the city centre with the seaside suburb of Glenelg. The smaller cities of Bendigo and Ballarat retain heritage tramway operations.
In Cairo, the urban tramway network is now defunct, but the express tramways linking Cairo with Heliopolis are still in operation, as is the relatively new tram system in the satellite town of Helwan 25km to the south.
In Alexandria, both the urban tramway network and the express tramway system serving the eastern suburbs are still in operation. The urban system operates yellow cars, included some acquired second hand from Copenhagen, on largely street track. The express tramway operates 3-car trains of blue cars, including some double-deck cars, on largely reserved track.
Trams operating on mainline railways
Around Karlsruhe and Saarbrücken, Germany, Bombardier Flexity Link trams partly use heavy-rail tracks, sharing these tracks with heavy-rail trains. In the Netherlands this was first applied on the RijnGouweLijn. This allows commuters to ride directly into the city centre, rather than having to take a mainline train as far as a central station and then change to a tram.
Some of the issues involved in such schemes are:
- compatibility of the safety systems
- power supply of the track in relation to the power used by the vehicles (different voltages, and third rail vs overhead wires)
- width of the vehicles in relation to the position of the platforms
- height of the platforms
The River LINE in New Jersey operates on Conrail freight trackage, but freight trains only run at night, when light rail trains don't run, and light rail provides the only passenger service on the line.
Third-rail power for trams
In the French city of Bordeaux, Citadis trams are powered by a third rail even in the city centre, where the tracks are not always segregated from pedestrians and cars. Safety is ensured by placing the third rail between the other two, and dividing it into eight-metre sections, each of which is only powered while it is completely covered by a tram. There is therefore no risk of a person or animal coming into contact with a live rail. In outer areas, the trams switch to conventional overhead wires. See this LRTA report for more information.
- urban rail transit
- urban heavy rail
- List of light-rail transit systems
- Bus Rapid Transit
- cable car
- people mover
- electric trolleybus
- public transport
- General Motors Streetcar Conspiracy
- List of transport museums
- Perley A. Thomas Car Works
- Poznanski Szybki Tramwaj
- Streetcar suburb
- Thomas Built Buses, Inc.
- Tram stop
- Ultra low floor
- Overhead lines
- A Streetcar Named Desire
- Frank J. Sprague
- History of Richmond, Virginia
- List of Canadian urban rail systems
- Table of Light Rail Transit Agencies in the United States
- Light Rail Transit Association (GB)
- Light Rail Central (US/CA)
- Light Rail Now advocacy (US)
- Light Rail Netherlands (NL) in English, Nederlands, Русский язык, Deutsch, Français, Español
- The Library of Congress has a movie of Armour's electric trolley, circa 1897. Search for "Armour's+electric+trolley"
- Trams in Alexandria (EG)
- Light Rail Transit Association (GB)
- Light Rail Central (US/CA)
- Light Rail Now advocacy (US)
- Light Rail Atlas "Holland's Light Rail-pages for a world audience" (NL) varying content in multiple languages
- The Cable Building Broadway Cable car line (US/NY)
- Trams in Hungary (HU)
- Market Street Railway (US/CA)
- Tram in Europe (EU, Europe)
- History of trams in Cieszyn, Poland (PL)
- National Capital Trolley Museum (US/MD)
- APTA Heritage Trolley Systems New Orleans page
- German National Tramway Collection, Hannover Tramway Museum Wehmingen(DE)
- British National Tramway Museum, Crich(GB)
- Reader's Companion to American History, Public Transportation: The Electric Streetcar
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