On November 8, 2020, the mobilization meeting for the Ya’an-Nyingchi section of the Sichuan-Tibet Railway was held at the same time as the Sejila Mountain Tunnel and the Dadu River Bridge, which are the control projects of the Sichuan-Tibet Railway. Construction of the Yalin Section of the Sichuan-Tibet Railway officially started.

The Sichuan-Tibet Railway has been planned for one hundred years, and the survey process lasted for 70 years. The entire line has an operating length of 1,567 kilometers. It starts from Chengdu in Sichuan Province in the east and passes through Ya'an, Kangding, Qamdo, Nyingchi and Shannan in the west, and finally Lhasa, the capital of the Tibet Autonomous Region. The Chengdu-Ya'an section of the Sichuan-Tibet Railway was put into operation in December 2018, and the construction of the Lhasa-Nyingchi section started in June 2015. The project is currently progressing smoothly. The newly-built main line from Ya'an to Linzhi is 1011 kilometers, with a design speed of 120 to 200 kilometers per hour. The total investment of the project is as high as 319.8 billion yuan.

According to reports, the Ya’an-Nyingchi section is the most difficult and dangerous part of the Sichuan-Tibet Railway, and its construction is the most difficult in the world. Among them, the newly-built main line of the Yalin section is 1011 kilometers, of which the total length of bridge and tunnel is 965.74 kilometers, and the bridge-to-tunnel ratio is as high as 95.8%. In particular, there are 72 new tunnels with a total length of 851.48 kilometers. In other words, the section from Ya'an to Linzhi was built on a bridge in addition to being built in a tunnel, and there are very few railways paved on flat ground.

What is particularly difficult is that among the 72 tunnels with a total length of 851.48 kilometers from Ya'an to Linzhi, there are many extra-long tunnels with a length of more than 30 kilometers, of which the longest tunnel is the Yigong Tunnel of 42.5 kilometers. The Sejila Mountain Tunnel started this time has a total length of 37.9 kilometers, surpassing the Xinguanjiao Tunnel (32 kilometers in total length), which is known as the "first railway tunnel in China". In addition, the Duomuge Tunnel is 36 kilometers long, Zeduoshan Tunnel is 32.8 kilometers, Zila Mountain Tunnel is 32.7 kilometers, Mila Mountain Tunnel is 29.4 kilometers, Yela Mountain Tunnel is 28.6 kilometers, Haizishan Tunnel is 25 kilometers, and Boshu Laling Tunnel is 25 kilometers. 23.6 kilometers and so on. Most of these tunnels are built on the roof of the world, in iceberg canyons, and are completely beyond the difficulty level of all existing construction projects on the earth.

The Yalin Section of the Sichuan-Tibet Railway has a planned construction period of 3,651 days. The construction will start on November 8, 2020 and be completed on November 9, 2030. The Sichuan-Tibet Railway connects Chengdu, Sichuan and Lhasa, Tibet. It is the second railway artery to Tibet after the Qinghai-Tibet Railway. After the entire line is completed and opened to traffic, the railway travel time from Chengdu to Lhasa will be shortened from 36 hours to about 12 hours. Editor/He Yuting