Section 5: Urban Light Rail

Urban light rail, subways, and modern trams are often confused. Even experts have differing views on classifying these three modes of transportation. The general public frequently mixes up subways and light rail, while experts tend to categorize light rail and trams together. However, there are distinctions among them. Subways are mostly underground with a small section elevated, light rail is mostly elevated with a small section at ground level, and trams are mostly on the ground except for crossings over intersections and rivers. This classification is based on their architectural structures. Another method of distinction is based on passenger volume per hour, which has been mentioned before. In terms of vehicle types, they are generally classified as A, B, and C, with A-type vehicles being 3 meters wide, B-type 2.8 meters, and C-type 2.6 meters. A and B types are used in subways, while C types are used in light rail. In reality, these standards are often mixed in actual construction, and some cities use high subway standards for their light rail construction, which is fine. Therefore, for convenience, in cities where subways, light rail, and trams coexist, they are collectively referred to as "rail transit," as Shanghai does.

Light rail, developed from trams, is an electric, wheel-rail-guided, medium-capacity urban rail transit system operating on dedicated tracks. It can reach speeds of 30 km/h and has a transport capacity of 15,000 to 30,000 passengers per hour, falling between subways and trams. The name "light rail" originated from a meeting of the International Union of Public Transport held in Brussels, Belgium, in March 1978, where "Light Rail Transit" (LRT) was designated as its English term. Light rail's most prominent advantages include lower investment, high transport capacity, quick construction, and easier management compared to subway systems. It is highly adaptable, serving as the backbone of transportation networks in small and medium-sized cities or as a supplement to those in large or megacities, with broad development prospects.

Similar to subways, light rail uses standard gauge tracks of 1435 mm, with ballast-laid tracks on bridges. Power supply requires contact nets on one side of the viaduct, receiving electricity through the pantograph on the top of light rail vehicles. The train signaling control system is similar to that of subways. Light rail stations are typically elevated, mostly using side platforms, requiring passengers to go up and down stairs. Stations can be constructed using reinforced concrete frame structures, bridge structures, or combinations of both. Reinforced concrete frame structures are suitable for large land areas and large station sizes, capable of being built in 2 to 3 layers. Bridge structures are suitable for small land areas, low passenger volumes, and small station sizes.

Currently, operational light rail systems in China include Changchun Light Rail, the first in China, opened in 2002; Tianjin Jinbin Light Rail, opened in 2003; and Dalian Light Rail Lines 3 and 7, opened in 2003 and 2009, respectively. Due to its many advantages and lower cost compared to subways, many other cities in China are also planning to build light rail systems.