Ministry of Transport has informed, the "First Rail Tunnel" in the Upper Yangtze River-the double-line Chongqing Rail Transit Line 27 Crossing River Tunnel was opened on November 25. Tunnel crossing the river filled the gap in Chongqing's transportation field without tunnels to cross the river.

Cross-river tunnel length is 3,212 meters long. Tunnel is built under a deep narrow river valley. Ground is mainly sand and mud stone inter layers, with a pebble layer covering the bottom, strong permeability and poor adhesion. This all brings high risks for construction. Therefore important safety and construction measures were taken to minimize risks. First digital twin of project created. Intelligent warning measures installed. Against water ingress high pressure seals installed and so on.

https://www.mot.gov.cn/jiaotongyaowen/202411/t20241127_4160171.html