At 9:00 on January 26, the main tunnel of No. 2 inclined shaft and the main tunnel of No. 3 inclined shaft of the Chongli Tunnel, a controlling project on the entire Taichong section of the newly built Taixi Railway undertaken by China Railway 16th Bureau Group as a supporting project for the 2022 Winter Olympics, successfully broke through. This marks that the Taichong section of the Taixi Railway has achieved full-line breakthrough after 317 days of construction, 4 months ahead of the planned schedule, setting the fastest construction record in the history of domestic conventional railway construction and laying a solid foundation for the full line's completion and opening to traffic by the end of this year.

　　The Taixi Railway starts from Taizicheng Station on the Beijing-Zhangjiakou High-Speed Railway in the south and ends at Xilinhot Station in the north. It passes through Chongli District, Zhangbei County, Guyuan County, Taibus Banner, Saibei Management District, and Zhenglan Banner. The Taizicheng-Chongli section is the only rail transit supporting line connecting the core competition area of the Winter Olympics and the Chongli urban area, and will provide important transportation support for the 2022 Winter Olympics. It has a total length of 15.864 km and includes one bridge, two tunnels, as well as station yards, subgrade, and other construction content. The total length of bridges and tunnels is 14.678 km, accounting for 92.52%.

　　The Heping Tunnel and Chongli Tunnel on the Taizicheng-Chongli section are key and difficult projects on the entire line. Because the surrounding rock at the tunnel construction locations is Grade III and Grade IV, broken and unstable, and the area is water-rich, with a maximum daily water inflow of 35,000 cubic meters, great difficulties were brought to construction production. The project department used technologies such as ground-penetrating radar and tunnel seismic prediction (TSP) to analyze the surrounding rock conditions of the tunnel in advance, providing technical and safety guidance for tunnel face excavation. It also adopted a combination of multi-stage pump station relay drainage and high-power single-stage drainage to overcome construction difficulties such as large water inflow and reverse-slope drainage in long inclined shafts, achieving water-free operation inside the tunnel and effectively ensuring excavation progress and safety.

　　The project has a tight schedule and heavy tasks. Since the project was awarded on January 19, 2020, China Railway 16th Bureau has carefully planned, worked day and night, strengthened resource allocation, innovated construction techniques, and focused on solving project development difficulties. It successively overcame a series of unfavorable factors such as material shortages caused by the pandemic, traffic controls and personnel flow restrictions, extreme cold of "minus 30°C", and variable tunnel geological conditions, achieving excellent results including the breakthrough of the Heping Tunnel 154 days ahead of schedule and the breakthrough of all tunnels on the line 114 days ahead of schedule.

　　It is reported that after the project is completed and opened to traffic, it will connect the two core areas of Zhangjiakou Chongli District, the main venue for the snow events of the 2022 Winter Olympics, and the Taizicheng Winter Olympic Village. The railway travel time from Taizicheng to the Chongli urban area will be only about 6 minutes. In the future, after the entire Taixi Railway is completed, the railway travel time from Xilinhot to Beijing will also be shortened to about 6 hours.