On June 12, with the sound of the final blast, the Zhangjiacun Tunnel on the newly built Chongqing–Wanzhou high-speed railway was successfully holed through. As the first tunnel on the entire line to be completed, it marks an important achievement in the standardized construction of tunnels on the project and provides valuable experience for subsequent tunnel excavation.

It is reported that the Zhangjiacun Tunnel was designed by China Railway Eryuan Engineering Group and constructed by China Railway 11th Bureau Group. It is a single-tube, double-track tunnel designed for a speed of 350 km/h, with shallow cover, poor geological conditions, high construction difficulty and high safety risk. The contractor formulated a dedicated tunnel construction plan, strengthened the deployment of personnel and machinery, and dynamically adjusted blasting parameters during construction according to tunnel cover depth and surrounding rock conditions; it strictly implemented the tunnel face acceptance procedure and standardized the construction process; and it carried out the process inspection declaration procedure, rigorously controlled the process, and ensured proper sequencing of works and logistical support.

It is understood that the newly built Chongqing–Wanzhou high-speed railway has a main line length of 250.91 km. It is a high-speed railway that serves both the northbound and eastbound routes out of the Southwest region and intercity passenger flows between Chongqing and Wanzhou, and is an important component of the Beijing–Kunming and Baotou–Haikou corridors of the national "Eight Vertical and Eight Horizontal" high-speed rail network. The project starts at Chongqing East Station and passes through Nan'an, Banan, Fuling, Fengdu and Zhongxian in Chongqing before finally reaching Wanzhou. Once completed, the travel time from Chongqing to Wanzhou will be shortened to less than one hour, effectively promoting the construction of the Chengdu–Chongqing economic circle and the economic and social development of major cities along the Yangtze River.