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Light rail is a form of urban passenger transportation that consists of relatively light weight vehicles that have steel wheels and run on steel rails that are basically the same as those used by conventional railroads. The technology of light rail is very similar to that of streetcars (also called trams and trolleys), and in some cases light rail vehicles actually run on the same tracks as streetcars for part of their trips. The main difference is that light rail is usually faster because it has fewer stops and because much or most of the right of way is separated from automobile traffic. Light rail offers some important advantages over other modes of urban transportation. For example, as compared with busses, it creates less air pollution and noise, is generally faster, has a greater passenger capacity and is generally preferred by riders. As compared with conventional heavy rail rapid transit (i.e., subways and elevated lines) it is usually much cheaper to construct and more flexible because it can also operate in streets rather than requiring that all of the right of way be completely segregated. As compared with commuter rail, light rail is usually much cheaper to construct and operate, has a faster acceleration (because of the lighter vehicles) and is more flexible with regard to routing (because it can accommodate sharper curves, can run on streets, etc.). Most light rail systems are electrically powered using overhead wires. However, some systems, including some new ones, obtain their power through alternative means, including through third rails or on-board diesel engines. Research is also being carried out on the use of fuel cells as a power source. Although some people criticize light rail as being an old fashioned technology, the truth is that it is no older than other modes and has experienced much technological advance in recent years. One of the biggest advances has been the development of low floor vehicles, in which the floor is at the same level as the curb or other low loading platform. This makes it much easier for people to enter and exit, particularly the elderly and people with disabilities, and thus reduces the amount of time required at each stop. Other advances include faster acceleration, lower power consumption, reduced noise output and electronic fare payment systems. Recently there has been a surge in the construction and expansion of light rail systems in the United States and other countries.1 This is a result of a growing awareness of the advantages of this mode of transportation, improvements in light rail technology, rising oil prices and mounting concern about climate change and the adverse health effects from automobile emissions.
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Created February 19, 2007. |