The Chongqing Rail Transit (branded as CRT; also known as Chongqing Metro) is the rapid transit system in the city of Chongqing, China. In operation since 2005, it serves the transportation needs of the city's main business and entertainment areas in downtown as well as the inner suburbs. As of December 2023, CRT consists of twelve lines with a total track length of 561.18 km (349 mi). Lines 1, 4, 5, 6, 9, 10, 18, the Loop line, Jiangtiao line, and Bitong line are conventional heavy-rail metro lines, while Lines 2 and 3 are high-capacity monorails. To keep up with urban growth, construction on several other lines is under way.
The Chongqing Rail Transit is a unique transit system owing to the nature of Chongqing being a densely populated yet mountainous city with multiple river valleys. Two lines use heavy-monorail technology, leveraging the ability to negotiate steep grades and tight curves and rapid transit capacity. They are capable of transporting 32,000 passengers per hour per direction. However the busiest section of Line 3 reaches a peak passenger volume of 37,700 pphpd in 2019. At 98 km (61 mi), the system's two monorail lines form the longest monorail system in the world, with Line 3 being the world's longest single monorail line. The length and the capacity of its monorail network both also make it the world's busiest monorail system, with a total of 94 million and 250 million rides in 2015 on Line 2 and Line 3, respectively. Line 3 is therefore the world's busiest single monorail line.
