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, the controlling project of the entire Taichong section of the newly-built Taixi Railway undertaken by China Railway 16th Bureau Group, a supporting project for the 2022 Winter Olympics, were successfully connected. This marks the full-line breakthrough of the Taichong section of the Taixi Railway after 317 days of construction, 4 months ahead of the scheduled construction period, creating the fastest construction record in the history of domestic conventional railway construction and laying a solid foundation for the full-line completion and opening to traffic by the end of this year.

The Taixi Railway starts from Taizicheng Station of 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 to 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 kilometers, including 1 bridge, 2 tunnels, and station yard, subgrade, and other construction contents. The total length of bridges and tunnels is 14.678 kilometers, accounting for 92.52%.

The Heping Tunnel and Chongli Tunnel in the Taizicheng to Chongli section are key and difficult projects of the entire line. Due to the surrounding rock grade of III and IV at the tunnel construction location, which is broken and unstable, and located in a water-rich zone with a maximum daily water inflow of 35,000 cubic meters, great difficulties have been brought to construction production. The project department used technologies such as geological radar and tunnel seismic prediction (TSP) to analyze the surrounding rock conditions of the tunnel in advance, providing technical and safety guidance for the excavation of the working face. 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 of long inclined shafts, achieving water-free operation in 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 has successively overcome a series of unfavorable factors such as material shortages caused by the epidemic, traffic control and personnel flow restrictions, extreme cold of "minus 30°C", and variable tunnel geological conditions, achieving excellent results such as the Heping Tunnel breakthrough 154 days ahead of schedule and the entire line's tunnel breakthrough 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 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.