Section 2: Development of urban rail transit worldwide

The rise of urban rail transit can be attributed directly to severe traffic congestion. Take Beijing as an example; the average speed of cars on main roads has halved compared to a decade ago and continues to decline by 2 km/year. Bus speeds have also plummeted from 40 km/h in the 1960s to just 10 km/h today. Without alternative transportation, urban traffic would soon collapse. Fortunately, metro, light rail, and other forms of rail transit have emerged as key solutions, saving cities from this dire situation.

Since the construction of the first metro in London over 130 years ago, urban rail transit technology has continuously evolved, diversifying into light rail, trams, monorails, and more. In 1890, London opened the world's first electric metro line, followed by Chicago's steam-powered metro in 1892 (electrified three years later). Paris's metro debuted in 1900, and Berlin's in 1902. Tokyo, Moscow, and others soon followed, with Moscow's metro becoming renowned for its artistry and world-leading passenger volume (3.2 billion annually). Beijing's metro opened in 1969, Tianjin was the second city to build one, and Shanghai the third. Today, China's million-plus cities are constructing or applying for metro systems, greatly benefiting residents' commutes.

Light rail, next to metro in significance, originally referred to trams. The world's first tram appeared in Virginia, USA, in 1888, and within three decades, 370 American cities operated trams. China wasn't far behind; Beijing, Shanghai, Tianjin, and others saw a tram boom in the early 20th century. However, as cars became more prevalent, trams faded away. Modern advancements have revived trams as clean, eco-friendly, and swift transportation, favored by many cities. Modern trams now operate in Dalian, Changchun, Tianjin's Binhai New Area, etc. The contemporary concept of light rail, distinct from modern trams, offers capacity between metro and trams, often appearing as elevated lines in cities. Notable domestic light rail systems include Shanghai's Pearl Line and Tianjin's Jinbin Light Rail.

Monorail, often called the "sky train," runs on a single track, either straddling or hanging from it. This unique mode of transportation dates back to 1821 in the UK, initially used for horse-drawn carts at docks. France launched its straddle monorail in 1888, and Germany invented the suspended monorail in 1893. Due to its low capacity, slow speed, and high technical requirements, monorail hasn't gained global popularity. China's first monorail opened in Chongqing in 2004.