Light rail is an important form of urban rail construction and the fastest growing form of rail transit in the world today.The light rail has a smaller locomotive weight and passenger capacity than the average train. The rails used are light in weight and only 50kg per meter, hence why it is called "light rail".

The light rail in urban rail transit corresponds to the "Metro".Compared with light rail, trams and rubber-guided trains are completely different in technology, so they are not part of the light rail system.

Characteristics include: (1) automatic signal system for train operation (2) dedicated rail and station for train operation (3) maximum speed is 80 km/h (4) max. train grouping is 4 knots (5) the hourly delivery 10,000 to 30,000 people.

Urban light rail has the advantages of large volume, high speed, low pollution, low energy consumption, on-time operation while being high safety.Urban light rail and subway（metro）, urban railways and other forms of rail transit constitute the urban rapid rail transit system.It can effectively alleviate the tension between population and transportation resources, cars and transportation facilities.