LHASA, Aug. 15 (Xinhua) -- A second railway line in southwest China's Tibet Autonomous Region, an extension of the Qinghai-Tibet railway, the world's highest, was officially put into use on Friday.

The 253-km railway line links the regional capital Lhasa and Xigaze, the second-largest city in the region. It reduces the travel time between the two cities from the current four hours by highway to around two hours.

Tickets for the new line went on sale Friday. The first passenger train is scheduled to leave Lhasa for Xigaze at 9 a.m. Saturday.

Construction of the railway started in 2010 with an investment of 13.28 billion yuan (2.16 billion U.S. dollars).