A few light rail networks tend to have characteristics closer to rapid transit or even commuter rail; some of these heavier rapid transit-like systems are referred to as light metros. Other light rail networks are tram-like in nature and partially operate on streets.
Light rail systems are found throughout the world, on all inhabited continents. They have been especially popular in recent years due to their lower capital costs and increased reliability compared with heavy rail systems.
Modern light rail technology has primarily West German origins, since an attempt by Boeing Vector to introduce a new American light rail vehicle was a technical failure. After World War II, the Germans retained many of their streetcar networks and evolved them into model light rail systems (Stadtbahnen).
Except for Hamburg, all large and most medium-sized German cities maintain light rail networks. The basic concepts of light rail were put forward by H. Dean Quincy in 1962 in an article in Traffic Quarterly called “Major Urban Corridor Facilities: A New Concept”.
Britain began replacing its run-down local railways with light rail in the 1980s, starting with the Type and Wear Metro and followed by the Docklands Light Railway (DLR) in London. The trend to light rail in the United Kingdom was firmly established with the success of the Manchester Metrolink system, which opened in 1992.
The Metrolink light rail in St. Louis, Missouri, United Stateside term light rail was coined in 1972 by the U.S. Urban Mass Transportation Administration (MTA; the precursor to the Federal Transit Administration) to describe new streetcar transformations that were taking place in Europe and the United States. In Germany the term Stadtbahn (to be distinguished from Spahn, which stands for Stadtschnellbahn) was used to describe the concept, and many in MTA wanted to adopt the direct translation, which is city rail (the Norwegian term, by bane, means the same).
The infrastructure investment is also usually lighter than would be found for a heavy rail system. Electrically propelled rail vehicles operate singly or in trains.
ART provides a wide range of passenger capabilities and performance characteristics at moderate costs.” ...a mode of transit service (also called streetcar, tramway, or trolley) operating passenger rail cars singly (or in short, usually two-car or three-car, trains) on fixed rails in right-of-way that is often separated from other traffic for part or much of the way.
Light rail vehicles are typically driven electrically with power being drawn from an overhead electric line via a trolley or a panto graph ; driven by an operator on board the vehicle; and may have either high platform loading or low level boarding using steps.” The use of the generic term light rail avoids some serious incompatibilities between British and American English.
The word tram, for instance, is generally used in the UK and many former British colonies to refer to what is known in North America as a streetcar, but in North America tram can instead refer to an aerial tramway, or, in the case of the Disney amusement parks, even a land train. Many North American transportation planners reserve streetcar for traditional vehicles that operate exclusively in mixed traffic on city streets, while they use light rail to refer to more modern vehicles operating mostly in exclusive rights of way, since they may operate both side-by-side targeted at different passenger groups.
The difference between British English and American English terminology arose in the late 19th century when Americans adopted the term “street railway”, rather than “tramway”, with the vehicles being called “streetcars” rather than “trams”. Some have suggested that the Americans' preference for the term “street railway” at that time was influenced by German emigrants to the United States (who were more numerous than British immigrants in the industrialized Northeast), as it is the same as the German term for the mode, Straßenbahn (meaning “street railway”).
A further difference arose because, while Britain abandoned all of its trams except Blackpool after World War II, eight major North American cities (Toronto, Boston, Philadelphia, San Francisco, Pittsburgh, Newark, Cleveland, and New Orleans) continued to operate large streetcar systems. When these cities upgraded to new technology, they called it light rail to differentiate it from their existing streetcars since some continued to operate both the old and new systems.
The opposite phrase heavy rail, used for higher-capacity, higher-speed systems, also avoids some incompatibilities in terminology between British and American English, as for instance in comparing the London Underground and the New York City Subway. Metrolink in Manchester city center, England, is an example of street-level light railroad Coast's G:Link Light Rail runs on a mix of dedicated right of way, tunnels and at grade intersectionsSome light rail networks feature extensive underground sections, like the Edmonton ART in Canada. The Tenerife Tram in Tenerife, Spain, includes some operation at street level, but separated from other traffic to varying definitions, it is hard to distinguish between what is called light rail, and other forms of urban and commuter rail.
Conversely, some lines that are called light rail” are in fact very similar to rapid transit ; in recent years, new terms such as light metro have been used to describe these medium-capacity systems. The most difficult distinction to draw is that between light rail and streetcar or tram systems.
There is a significant amount of overlap between the technologies, many of the same vehicles can be used for either, and it is common to classify streetcars or trams as a subcategory of light rail rather than as a distinct type of transportation. The traditional type, where tracks and trains run along the streets and share space with road traffic.
Stops tend to be very frequent, but little effort is made to set up special stations. A more modern variation, where the trains tend to run along their own right-of-way, separated from road traffic.
Tracks are highly visible, and in some cases significant effort is expended to keep traffic away through the use of special signaling, level crossings with gate arms, or even a complete separation with non-level crossings. At the highest degree of separation, it can be difficult to draw the line between light rail and metros.
In Europe and Asia, the term light rail is increasingly used to describe any rapid transit system with a fairly low frequency or short trains compared to heavier mass rapid systems such as the London Underground or Singapore's Mass Rapid Transit. However, upon closer inspection, these systems are better classified as light metro or people movers.
This phenomenon is quite common in East Asian cities, where elevated metro lines in Shanghai, Wuhan, and Dalian in China; and Jakarta, Greater Jakarta and Palembang in Indonesia are called light rail lines. In North America, such systems are not usually considered light rail.
For example, the Los Angeles Metro Rail's L Line light rail” has sections that could alternatively be described as a tramway, a light metro, and, in a narrow sense, rapid transit. This is especially common in the United States, where there is not a popularly perceived distinction between these different types of urban rail systems.
The development of technology for low-floor and catenary-free trams facilitates construction of such mixed systems with only short and shallow underground sections below critical intersections as the required clearance height can be reduced significantly compared to conventional light rail vehicles. Belgium's Coast Tram operates over almost 70 km and connects multiple town centers. In some areas, light rail” may also refer to any rail line with frequent low speeds or many stops in a short distance.
Reference speed from major light rail systems, including station stop time, is shown below. For example, the Siemens S70 LRS used in the HoustonMETRORail and other North American ART systems have a top speed of 106 kilometers per hour (66 mph) while the trains on the all-underground Montreal Metro can only reach a top speed of 72 kilometers per hour (45 mph).
The main difference is that Montreal Metro and New York City Subway trains carry far more passengers than any North American ART system, and the trains have faster acceleration, making station-to-station times relatively short in their densely populated urban areas. Most light rail systems serve less densely populated cities and suburbs where passenger traffic is not high, but low cost combined with high top speed may be important to compete with automobiles.
Older standard-gauge vehicles could not negotiate sharp turns as easily as narrow-gauge ones, but modern light rail systems achieve tighter turning radii by using articulated cars. Using standard gauge also allows light rail vehicles to be moved around, conveniently using the same tracks as freight railways.
Another factor favoring standard gauge is that accessibility laws are making low-floor trams mandatory, and there is generally insufficient space for wheelchairs to move between the wheels in a narrow-gauge layout. Furthermore, standard-gauge rolling stock can be switched between networks either temporarily or permanently and both newly built and used standard-gauge rolling stock tends to be cheaper to buy, as more companies offer such vehicles.
Energy efficiency for light rail may be 120 passenger miles per gallon of fuel (or equivalent), but variation is great, depending on circumstances. Roads have ultimate capacity limits that can be determined by traffic engineering.
They usually experience a chaotic breakdown in flow and a dramatic drop in speed (a traffic jam) if they exceed about 2,000 vehicles per hour per lane (each car roughly two seconds behind another). Since most people who drive to work or on business trips do so alone, studies show that the average car occupancy on many roads carrying commuters is only about 1.5 people per car during the high-demand rush hour periods of the day.
This combination of factors limits roads carrying only automobile commuters to a maximum observed capacity of about 3,000 passengers per hour per lane. By contrast, light rail vehicles can travel in multi-car trains carrying a theoretical ridership up to 20,000 passengers per hour in much narrower rights-of-way, not much more than two car lanes wide for a double track system.
They can often be run through existing city streets and parks, or placed in the medians of roads. If run in streets, trains are usually limited by city block lengths to about four 180-passenger vehicles (720 passengers).
Operating on two-minute headway using traffic signal progression, a well-designed two-track system can handle up to 30 trains per hour per track, achieving peak rates of over 20,000 passengers per hour in each direction. More advanced systems with separate rights-of-way using moving block signalling can exceed 25,000 passengers per hour per track.
Most light rail systems in the United States are limited by demand rather than capacity (by and large, most American ART systems carry fewer than 4,000 persons per hour per direction), but Boston's and San Francisco's light rail lines carry 9,600 and 13,100 passengers per hour per track during rush hour. Elsewhere in North America, the CalgaryC-Train and Monterrey Metro have higher light rail ridership than Boston or San Francisco.
The Manila Light Rail Transit System is one of the highest capacity ones, having been upgraded in a series of expansions to handle 40,000 passengers per hour per direction, and having carried as many as 582,989 passengers in a single day on its Line 1. BRT's systems can exhibit a more diverse range of design characteristics than ART, depending on the demand and constraints that exist, and BRT using dedicated lanes can have a theoretical capacity of over 30,000 passengers per hour per direction (for example, the Guangzhou Bus Rapid Transit system operates up to 350 buses per hour per direction).
For the effective operation of a bus or BRT system, buses must have priority at traffic lights and have their own dedicated lanes, especially as bus frequencies exceed 30 buses per hour per direction. The higher theoretical of BRT relates to the ability of buses to travel closer to each other than rail vehicles and their ability to overtake each other at designated locations allowing express services to bypass those that have stopped at stations.
In terms of cost of operation, each bus vehicle requires a single driver, whereas a light rail train may have three to four cars of much larger capacity in one train under the control of one driver, or no driver at all in fully automated systems, increasing the labor costs of BRT systems compared to ART systems. The peak passenger capacity per lane per hour depends on which types of vehicles are allowed at the roads.
Typically, roadways have 1,900 passenger cars per lane per hour (proof). Career + NASCAR + light rail Low volume9001,6502,250 Medium volume9002,3503,250 High volume9003,4004,600 Sources: Edson & Tennyson, 2003 An analysis of data from the 505-page National Transportation Statistics report published by the US Department of Transportation shows that light rail fatalities are higher than all other forms of transportation except motorcycle travel (31.5 fatalities per 100 million miles).
However, the National Transportation Statistics report published by the US Department of Transportation states that “Caution must be exercised in comparing fatalities across modes because significantly different definitions are used. The new Ion system in Ontario's Waterloo Region spurred massive development along its route before opening cost of light rail construction varies widely, largely depending on the amount of tunneling and elevated structures required.
Seattle's new light rail system is by far the most expensive in the US, at $179 million per mile, since it includes extensive tunneling in poor soil conditions, elevated sections, and stations as deep as 180 feet (55 m) below ground level. This results in costs more typical of subways or rapid transit systems than light rail.
At the other end of the scale, four systems (Baltimore, Maryland; Camden, New Jersey; Sacramento, California; and Salt Lake City, Utah) incurred construction costs of less than $20 million per mile. Over the US as a whole, excluding Seattle, new light rail construction costs average about $35 million per mile.
However, freeways are frequently built in suburbs or rural areas, whereas light rail tends to be concentrated in urban areas, where right of way and property acquisition is expensive. ART cost efficiency improves dramatically as ridership increases, as can be seen from the numbers above: the same rail line, with similar capital and operating costs, is far more efficient if it is carrying 20,000 people per hour than if it is carrying 2,400.
The Calgary, Alberta, C-Train used many common light rail techniques to keep costs low, including minimizing underground and elevated track age, sharing transit malls with buses, leasing rights-of-way from freight railroads, and combining ART construction with freeway expansion. As a result, Calgary ranks toward the less expensive end of the scale with capital costs of around $24 million per mile.
Thus, Calgary's capital cost per passenger was much lower than that of San Diego. Compared to buses, costs can be lowed due to lower labor costs per passenger-mile, higher ridership (observations show that light rail attracts more ridership than a comparable bus service) and faster average speed (reducing the number of vehicles needed for the same service frequency).
While light rail vehicles are more expensive to buy, they have a longer useful life than buses, sometimes making for lower life-cycle costs. Some light rail systems, such as the St. Louis Metrolink, allow bicycles on the trains, but only in the rear sections of cars.
Some light rail lines, like San Francisco's, allow only folding bicycles on board. The Trillium Line in Ottawa was built along a freight railway and is still occasionally used by freight traffic overnight. Around Karlsruhe, Kassel, and Saarbrücken in Germany, dual-voltage light rail trains partly use mainline railroad tracks, sharing these tracks with heavy rail trains.
This allows commuters to ride directly into the city center, rather than taking a mainline train only as far as a central station and then having change to a tram. In France, similar tram-trains are planned for Paris, Mulhouse, and Strasbourg ; further projects exist.
When electric streetcars were introduced in the late 19th century, conduit current collection was one of the first ways of supplying power, but it proved to be much more expensive, complicated, and trouble-prone than overhead wires. When electric street railways became ubiquitous, conduit power was used in those cities that did not permit overhead wires.
In Europe, it was used in London, Paris, Berlin, Marseille, Budapest, and Prague. In the United States, it was used in parts of New York City and Washington, D.C. Third rail technology was investigated for use on the Gold Coast of Australia for the G:link light rail, though power from overhead lines was ultimately utilized for that system.
This minimizes the risk of a person or animal coming into contact with a live rail. In outer areas, the trams switch to conventional overhead wires.
The Bordeaux power system costs about three times as much as a conventional overhead wire system, and took 24 months to achieve acceptable levels of reliability, requiring replacement of all the main cables and power supplies. Operating and maintenance costs of the innovative power system still remain high.
However, despite numerous service outages, the system was a success with the public, gaining up to 190,000 passengers per day. With its mix of right-of-way types and train control technologies, ART offers the widest range of latitude of any rail system in the design, engineering, and operating practices.
The challenge in designing light rail systems is to realize the potential of ART to provide fast, comfortable service while avoiding the tendency to over design that results in excessive capital costs beyond what is necessary to meet the public's needs. Alternative Differences Rapid transit Light rail vehicles (LRS) are distinguished from rapid rail transit (RRT) vehicles by their capability for operation in mixed traffic, generally resulting in a narrower car body and articulation in order to operate in a street traffic environment.
Since ART systems can operate in existing streets, they can often avoid the cost of expensive grade-separated subway and elevated segments that would be required with RRT. The latest generation of LRS is considerably larger and faster, typically 29 meters (95 ft) long with a maximum speed of around 105 kilometers per hour (65 mph).
A heritage streetcar may not have the capacity and speed of an LRC, but it will add to the ambiance and historic character of its location. Such railways are characterized by exclusive rights of way, advanced train control systems, short headway capability, and floor-level boarding.
These systems approach the passenger capacity of full metro systems, but can be cheaper to construct due to LRS generally being smaller, turning tighter curves and climbing steeper grades than standard RRT vehicles, and having a smaller station size. Interurban The term interurban mainly refers to rail cars that run through streets like ordinary streetcars (trams), but also between cities or towns, often through rural environments.
Some of them, like the Red Devils, the J. G. Brill Bullets, and the Electrolytes, were the high-speed railcars of their time, with an in-service speed of up to about 145 km/h (90 mph). The reason that the operator is so important is because the train tracks often share the streets with automobiles, other vehicles, and pedestrians.
Light rail trains are actually very sturdily built for passenger safety, and to reduce damage from impacts with cars. The latest generation of LRS has the advantage of partially or fully low-floor design, with the floor of the vehicles only 300 to 360 mm (11.8 to 14.2 in) above the top of the rail, a feature not found in either rapid rail transit vehicles or streetcars.
This allows them to load passengers, including those in wheelchairs or strollers, directly from low-rise platforms that are little more than raised sidewalks. Overhead lines supply electricity to the vast majority of light rail systems.
Some date from the beginning of the 20th century or earlier such as Toronto streetcar system, but many of the original tram and streetcar systems were closed down in the mid-20th century, with the exceptions of many Eastern Europe countries. Most light rail services are currently committed to articulated vehicles like modern LRS, i.e. trams, except large underground metro or rapid transit systems.
Continuing Developments in Light Rail Transit in Western Europe (PDF). “Defining an Alternative Future: The Birth of the Light Rail Movement in North America”.
From: 9th National Light Rail Transit Conference ^ Gregory L. Thompson (2003), Defining an Alternative Future: Birth of the Light Rail Movement in North America (PDF), Transportation Research Board. ^ Smile, Simon P. “Trams, Streetcars, and Light Rail Vehicles”.
M.J. Bradley & Associates, May 2007 ^ Matt Lorenz and Lily Elefteriadou (2000) A Probabilistic Approach to Defining Freeway Capacity and Breakdown (PDF), Transportation Research Board. ^ Tom Parkinson and Ian Fisher (1996) Rail Transit Capacity Archived 11 January 2009 at the Payback Machine, Transportation Research Board.
^ Transit Capacity and Quality of Service Manual, Transportation Research Board. ^ “CHIP Report 599: Default Values for Highway Capacity and Level of Service Analyses” (PDF).
^ “Highway Construction Cost Comparison Survey Final Report” (PDF). ^ Traffic and Highway Engineering By Nicholas J. Garber, Lester A. Hotel, p. 37 ^ Shaw, Mark (May–June 2006).
“Reinventing a Corridor: Denver's T. rex project nears completion after five years”. Joint International Light Rail Conference, St. Louis, Missouri.
^ “Bordeaux Light Rail Route Will Operate Without Overhead Lines” (Press release). ^ “99% AVAILABILITY AND EXCEPTIONALLY HIGH PASSENGER LEVELS : THE BORDEAUX URBAN TRAMWAY IS A RESOUNDING SUCCESS”.