At an altitude of 3,607 meters, the 16, 3 km long railway tunnel in Northwest China is the highest in the world and after completely linked up, it became operational on May 1.
The line that runs through the Qilian Mountains has two sections and passes over a bridge.
The construction works began in 2009. The 1,776 km line is designed for trains running at over 200 km per hour and will come into use at the end of 2014.
The new high-speed railway links Lanzhou, capital of Gansu, with Urumqi, capital of Xinjiang and runs the wind ravaged Gobi Desert.
The Lanxin railway line is expected to cut the train travel time between Lanzhou and Urumqi from about 20 hours to 8 hours.