BEIJING, Jan. 2 (Xinhua) -- Cities on the Chinese mainland built a record 968.77 km of urban rails in 2019, according to a report from the China Association of Metros.

At the end of last year, 40 cities had urban rail transit systems in operation, with a total length of 6,730.27 km.

Subways continued to be dominant among all types of urban rail transit. The length of subways reached 5,187.02 km in 2019, accounting for 77.07 percent of the total, while that of inner-city rapid rail transit hit 715.61 km, making up 10.63 percent of the total.

Shanghai, Beijing, Guangzhou, Chengdu and Nanjing were the top five cities in terms of the length of urban rail transit, said the report.

Last year, the National Development and Reform Commission, the country's top economic planner, approved new subway projects in Zhengzhou, Xi'an and Chengdu with a total investment of 342.58 billion yuan (about 48.9 billion U.S. dollars).