With all the recent discussion about the Purple Line, it seems pertinent to explore the reasons that light rail transit (LRT) is being considered for the UM Campus and the larger Washington region.
Before 1972, the term light rail did not exist. It was coined by the Urban Mass Transit Administration (now the Federal Transit Administration) to describe the upgrades of streetcar systems that were starting to become popular in the United States as a cheaper alternative to constructing heavy rail (metro) systems. The wave of new LRT systems started in Canada, when Edmonton opened North America’s first LRT system in 1978. San Francisco followed in 1980, starting the US trend. One could also argue that Boston’s Green Line, which has been operating as a streetcar tunnel since 1897, became a light rail line in 1975 when it began upgrades to modern LRT technology.

Light rail’s popularity stems from its cheapness. Light rail was originally implemented in cities of small to medium size, where a full-scale metro system was impractical. However as federal funding became more competitive and inflation drove construction costs up, many larger cities began to turn to light rail as well. It is perhaps the most versatile form of rail transit. While heavy rail systems like Metro are fully grade separated, LRT can operate in almost any context. Buffalo, New York’s light rail system is almost completely grade separated. Except for the southernmost 1.2 miles, the line is entirely in subway. The light rail systems in Dallas and Portland each have only one subway station; the rest are at grade. The T in Pittsburgh operates in a subway downtown, on its own right of way through most of the South Hills, and, in a few places–like Beechview, in-street with cars. Ridership is greatly varied. In some cities, Like Tacoma and Trenton, only a few thousand people board every day; in other places, light rail serves tens of thousands. The Green Line in Boston carries over 235,000 passengers on an average weekday.

The features which distinguish light rail from heavy rail and streetcars are in various categories. Because LRVs often travel in mixed rights of way, they use caternary (overhead) wires to power the vehicle. To overcome objections to these wires, several systems use diesel powered vehicles. Of note, Ottawa’s O-Train and NJ Transit’s River Line operate as “diesel multiple unit” LRVs. Still, caternary wires do provide benefits, such as fewer localized pollution sources. They can also be screened easily through different methods, such as planting street trees (see the Portland example above on the left). Capacity is another major distinguishing feature. LRV’s typically have much higher capacities than do streetcars, including the ability to be coupled into trains of several units. However, they are considered ‘light’ in the sense of their comparison to heavy rail, with which they cannot compete on high ridership lines. The two largest factors surrounding the selection of light rail as a mode are context and cost. Low density streetcar suburbs and suburban employment centers tend to be better suited to light rail because they lack the concentration of trip generators and destinations that heavy rail necessitates. Light rail is also chosen in situations where enough capital cannot be raised to construct a full-scale metro system.
Light rail is a safe, efficient, clean, and attractive mode of transportation. It will replace the crowded and often gridlocked Campus Drive that we know with one which is safer for pedestrians (after all, there’s nothing more dangerous than a car for a pedestrian), more accessible to the larger region, and which is more environmentally friendly.
Light rail systems have been springing up across the country, and will likely continue to do so. Here is a list of cities with light rail.
For photos, click on the links.
*Boston’s Green Line: upgraded to LRT in 1975, opened 1897
*San Francisco’s Muni Metro: upgraded to LRT in 1980
*San Diego Trolley: opened 1981
*Cleveland’s Blue and Green Lines: upgraded to LRT in 1981
*Buffalo Metro Rail: opened in 1984
*Portland’s MAX Light Rail: 1986
*Sacramento’s RTD Light Rail: 1987
*San Jose’s VTA Light Rail: 1987
*Pittsburgh’s T: 1987
*Los Angeles’ Light Rail Lines (Blue, Green, Gold): 1990
*Baltimore’s Light Rail: 1992
*Saint Louis Metrolink: 1993
*Denver RTD’s The Ride: 1994
*Dallas‘ DART: 1996
*Salt Lake City’s TRAX: 1999
*New Jersey’s Hudson-Bergen Light Rail: 2000
*Tacoma LINK: 2003
*Houston METRORail: 2004
*Minneapolis‘ Hiawatha Line: 2004
*Trenton-Camden River Line: 2004
*Newark Light Rail: 2006
*Charlotte’s LYNX will open on November 24th, 2007
*Phoenix’s METRORail is under construction, opening 2008
*Seattle’s Central LINK is under construction, opening 2009
*Norfolk just started construction on the Tide, opening 2010