BEIJING -- Three new metro lines opened on Sunday in Beijing, adding the city's total urban rail transit length to 879 kilometers, ranking first among Chinese metropolitans.

Wu Yulan, an official of the Beijing Municipal Commission of Transport, said that the three sections of metro lines include one east-west underground corridor through the city, which is also connected to many north-south rail transit lines, giving new options for people in big residential areas in the city.

Wu said Beijing's rail transit network currently boasts 522 stations, including 98 interchange stations.

Beijing has taken measures to ease traffic congestion by building more subway lines, which provide mass rapid transit solutions in the sprawling metropolis. Since Beijing Metro Line 1 was officially opened on Oct 1, 1969, to become China's first urban rail transit, Beijing has built the country's longest-operating urban rail transit network.

Wu said the extending rail transit network was developed to serve a better life for the people and to pursue high-quality development in the city.