Arguably, the two most important defining elements of trackwork for light rail systems are the construction of track in streets and the interface between the wheel of the light rail vehicles and the rails. Track in streets requires special consideration, especially with regard to the control of stray electrical current that could cause corrosion. These embedded tracks also need to provide a flangeway that is large enough for the wheels but does not pose a hazard to other users of the street.
Light rail vehicle wheels do not necessarily match those used in freight railroad service. Wheel diameters are usually much smaller, and the wheel tread is often much narrower. Light rail wheel flanges are often shorter and have a radically different contour than railroad wheels. These variations require special care in track design, especially in the design of special trackwork such as switches and frogs. The compatibility of the vehicle and track designs is a central issue in the development of a light rail system if both components are to perform to acceptable standards.
While light rail may need to share right-of-way (R/W) with pedestrians and vehicles, the designer should create an exclusive R/W for light rail tracks wherever possible. This will make operation more reliable and maintenance less expensive.
