On March 30, with the completion of the final blast, the 13,407-meter Baimashan Tunnel on the Chongqing-Qianjiang section of the Chongqing-Hunan High-Speed Railway was successfully holed through, laying a solid foundation for the early opening of the entire Chongqing-Hunan High-Speed Railway line.

　　The Baimashan Tunnel is located in Baima Town, Wulong District, Chongqing. Designed by China Railway Eryuan Engineering Group and constructed by China Railway 11th Bureau Group, it is the **longest tunnel** on the Chongqing-Qianjiang section of the Chongqing-Hunan High-Speed Railway and a key and difficult control project for the whole line. It is designed for a speed of 350 kilometers per hour and is a single-tube, double-track tunnel.

This shows construction machinery operating at the tunnel breakthrough face.

　　According to reports, the Baimashan Tunnel is a Class I high-risk tunnel. The gas-affected sections total 6,288 meters, accounting for 28.7% of the total length of the main tunnel and auxiliary adits. It contains a variety of unfavorable geological conditions, including karst, water-rich depressions, faults, soft rock, rockbursts, and coal mine goafs, posing high safety risks and great construction difficulties. In response to the unfavorable geology of the Baimashan Tunnel, construction personnel set up double cross adits in the middle of the tunnel to achieve short excavation of a long tunnel, gallery-type ventilation, downhill drainage, and disaster prevention and rescue. In response to the tunnel's gas risks, they combined automated gas monitoring with manual inspection and established an audible and visual alarm system, achieving automatic alarming and automatic power cutoff.

This is a photo taken on March 30 of the breakthrough site of the Baimashan Tunnel (drone photo).

　　According to reports, the Chongqing-Qianjiang section of the Chongqing-Hunan High-Speed Railway is an important part of the Xiamen-Chongqing corridor in the "eight vertical and eight horizontal" high-speed railway network under China's medium- and long-term railway network plan. Once the project is completed, travel time from Qianjiang, Chongqing to the main urban area will be shortened from the current 4 hours to less than 1 hour, greatly improving travel conditions for residents along the line.