On April 24, with the pouring of the final batch of concrete for the lining structure of Huahuiyuan Station, the lining structure of the first mined (underground-excavated) station on the entire western extension of Chongqing Rail Transit Line 4 was successfully completed. This also means that the western extension of Chongqing Rail Transit Line 4 has achieved the milestone of "topping out" its first station along the line.

Huahuiyuan Station is about 215 meters long and about 13 meters wide, located within Huahuiyuan Park, and is an island-type mined station. The completion of the station's lining structure construction means the station's main structure is finished, providing conditions for the subsequent secondary structure construction inside the station, station decoration and fit-out, and equipment installation.

Mined lining structure refers to the permanent support structure built with reinforced concrete and other materials along the perimeter of the mined station cavern to prevent deformation of the surrounding rock, equivalent to the main skeleton of a mined station and serving as the primary load-bearing structure.

The project is being built by Chongqing City Transportation Development & Investment Group Rail Transit Co., Ltd. and constructed by Power Construction Corporation of China. During construction, difficulties such as a narrow construction site and complex underground pipelines were overcome, and after more than 300 days and nights, the main lining structure construction of Huahuiyuan Station was successfully completed.

At present, the western extension of Rail Transit Line 4 has completed the topping out of 1 station and accumulated 8.1 kilometers of TBM tunneling.

According to reports, the line starts from Pangui Road Station in the west and ends at Min'an Avenue Station (already built) in the east. Once completed, it will operate through with Phase I and Phase II of Line 4. At that time, it will connect important areas such as the Dashiba cluster, Guanyinqiao cluster, Tangjiatuo cluster, and Longxing cluster, further densifying the rail transit network in the central urban area and facilitating travel for the general public.