Left line of key tunnel along Chengdu-Lanzhou Railway drilled through

(ECNS) -- The left line of the Yuelongmen Tunnel along the Chengdu-Lanzhou Railway was linked up in Mianyang City, Sichuan Province, on Sunday.

The tunnel, with a maximum depth of 1,445 meters, crosses the Longmen Mountains.

It is one of cross-mountain tunnels under construction with most construction difficulties in China.

The completion of the left line will lower the construction risk of the right line of the tunnel with high-intensity of gas and help the construction of the right line.

The Chengdu-Lanzhou Railway, with a designed speed of 200 kilometers per hour, is crucial to the Lanzhou-Guangzhou passage of China's railway network.

It is another railway at an altitude of 3,000 kilometers besides Qinghai-Tibet Railway.