Many congested cities have turned to Light Rail Transport (LRT) because these systems offer relative simplicity and versatility. For instance, in areas that cannot geographically handle a subway system, the light rail may operate high above street level. This LRT services the London docklands, providing convenient transportation through the industrial network.
Light-rail transit is an electric railway system that evolved from streetcar systems. Like streetcars, light-rail cars operate as single units or as short trains of two or three cars. Light rail is designed to use a variety of rights-of-way, providing more flexibility than the streetcar. In some cities, light-rail systems operate like streetcars in downtown areas but then move to reserved lanes of traffic to service outer neighborhoods. Light-rail systems may also operate in tunnels under congested areas or on elevated tracks mounted over city streets. Light rail is popular in Europe and is in use in several U.S. cities, including Portland, Oregon; San Diego, California; and Baltimore, Maryland. Light rail is a cheaper and more versatile alternative to older rail systems.