After 6-year hard work, the second section of Xinguanjiao Tunnel, which belongs to the second line of Xining-Golmud railway of Qinghai-Tibet railway, was completed successfully on June 18, 2013.

With a total length of 32.16 km, the extra-long Xinguanjiao Tunnel under construction in China is the world's longest railway tunnel at high altitude. When the railway opens to traffic, the run time of train will be shortened by two hours.

The second line of Xining-Golmud railway of Qinghai-Tibet railway covers a full length of 818km, and is the only railway connecting Qinghai Province and Tibet Autonomous Region. Its construction will provide a big boost to the economic development of Qinghai Province and Tibet Autonomous Region.