On July 21, the Langao No. 2 Tunnel, constructed by China Railway 14th Bureau Group under the commissioning of Shaanxi Passenger Dedicated Line Xicheng Company, officially commenced construction, marking new progress in the construction of the Kangyu section of the Xi'an–Chongqing High-Speed Railway.

The Langao No. 2 Tunnel on the Kangyu section of the Xi'an–Chongqing High-Speed Railway is located within Langao County, Ankang City. With a total length of 250 meters, it is a single-tube double-track tunnel with a maximum burial depth of approximately 53 meters, and its exit connects to Langao Station. The tunnel cross-section transitions from a standard radius of 6.65 m to a 9.5 m large span, and then to an 11.3 m radius, posing significant technical control challenges.

To ensure the smooth progress of tunnel construction, the client, Xicheng Passenger Dedicated Line Shaanxi Company, guided the contractor to complete works in accordance with the design, including the crown catchment ditch, permanent side and portal slope protection, portal reinforcement, temporary side and portal slope protection, and advance support, and the tunnel passed the entry-condition acceptance by the construction, design, and supervision units, meeting the requirements for tunnel entry construction. During construction, the contractor adopted steel arches, systematic anchor bolts, advance grouting small pipes, and mesh shotcrete to form a support system, used zoned blasting to reduce the disturbance of blasting vibration on the surrounding rock, strengthened monitoring and measurement of the surrounding rock, and reduced the impact of deformation on subsequent construction. At the same time, an intelligent management and control system was introduced, using access control, personnel positioning, video surveillance, gas monitoring, and emergency broadcasting to achieve coordinated organization and collaborative work across multiple working faces.

The Ankang–Chongqing section of the Xi'an–Chongqing High-Speed Railway is an important component of China's "Eight Vertical and Eight Horizontal" high-speed rail network, namely the Beijing–Kunming corridor (Jingkun Corridor) and the Baotou–Yinchuan–Haikou corridor (Bao (Yin) Hai Corridor). The line starts from Ankang West Station and passes through Ankang City in Shaanxi Province, Chengkou County in Chongqing Municipality, Dazhou City and Guang'an City in Sichuan Province, and Hechuan District and Beibei District in Chongqing Municipality, before entering the Chongqing hub at Chongqing West Station. A total of 11 stations are set up: Ankang West, Langao, Chengkou, Fanhui, Xuanhan South, Dazhou South, Dazhu, Guang'an East, Hechuan East, Beibei South, and Chongqing West, among which Chongqing West is an existing station and the others are newly built stations.

The Kangyu section of the Xi'an–Chongqing High-Speed Railway connects with the already-under-construction Xi'an–Ankang High-Speed Railway, forming a major high-speed rail corridor between Xi'an and Chongqing. Once the Xi'an–Chongqing High-Speed Railway is completed and opened to traffic, the travel time from Xi'an to Chongqing is expected to be shortened from about 6 hours at present to about 2.5 hours. This will further improve the railway network structure in the central and western regions, greatly facilitate travel for people along the line, and is of great significance for consolidating and expanding the achievements of poverty alleviation, comprehensively promoting rural revitalization, supporting urban-rural integration and coordinated regional development, and shaping a new pattern of large-scale development of the western region.