Definition: Light Rail
Light Rail is essentially a modern evolution of the
conventional trolley. The concept evolved largely in the German and Dutch
speaking countries of Europe in the decades after World War II. In this era
cities in the U.S., Canada, the U.K., and France, among other countries,
replaced their streetcars with buses, but in the German and Dutch-speaking
countries the streetcars were retained and upgraded.
The Transit Research Board definition is: "Light rail
transit is a metropolitan electric railway system characterized by its ability
to operate single cars or short trains along exclusive rights of way at ground
level, on aerial structures, in subways or, occasionally, in streets, and to
board and discharge passengers at track or car-floor level."
Key characteristics that distinguish light rail from
streetcars are the following:
- Track is segregated from traffic wherever possible
enabling higher operating speeds. Track is normally placed in reserved lanes
on streets, in separate reservations on or next to streets, on private right
of way similar to railroad lines, in subways, or on elevated structures. But
the lines can still negotiate sharp curves and steep grades, similar to
- Station spacing is usually further apart than on
streetcar lines, again to allow increased operating speed. Stations are also
typically more formally defined than on streetcar lines, often featuring
shelters, seating, passenger information, and fare machines.
- Cars are normally longer and more spacious. Most today
are articulated, meaning that they are made of several body sections connected
by a flexible joint that allows lengthy cars to bend as they negotiate sharp
curves and steep grades.
- Traditionally boarding of light rail cars, as with
streetcars, is via steps from a low platform. However, several new light rail
systems have opted for high platforms level with the car floor. The latest
trend is to use cars specially built with the floor over some or all of the
length of the car lowered to about 12 inches from the top of the rail,
providing ADA compliant accessibility from relatively low platforms and
speeding boarding and alighting for all passengers.
- Fares are often not collected on cars, to enable
boarding through many doors without a staff member collecting fares at the
door, and to speed loading. Modern systems typically use an honor system
requiring purchase of a ticket before boarding the car and use fare inspectors
to verify compliance randomly.
A modern light rail train in downtown Baltimore.
Light rail systems are normally less expensive to build
than heavy rapid transit systems (see Heavy Rail) as they require less and simpler
infrastructure. Light rail lines can carry more passengers through a given
corridor than buses or streetcars, but fewer than a heavy rapid transit system.
Surviving trolley systems in cities such as Boston,
Pittsburgh, and San Francisco have been upgraded to light rail status in recent
decades. Since 1981 many completely new light rail systems have been built in
cities such as San Diego, Portland (OR), Buffalo, Baltimore, St. Louis, and
Dallas to name just a few.