Recently, on the Tianshui-Longnan Railway Section I, constructed by Gansu Tianshui-Longnan Railway Company and implemented under the leadership of China Railway City Investment, with construction undertaken by China Railway No. 2 Engineering Group, the inclined shaft of the Liulin Tunnel completed its crown-removal (breakthrough) construction task. With this, all auxiliary adits of the Liulin Tunnel have been fully converted to main tunnel construction, laying a solid foundation for the early breakthrough of the tunnel.

The Liulin Tunnel has a total length of 15,152 meters and is an extra-long single-tube, single-track tunnel. The tunnel site is located in the middle-mountain area of the Qinling Mountains, where the stratigraphic lithology is relatively complex, tectonic activity is intense, and geological hazards are well developed. The maximum burial depth is approximately 422 meters, and construction risk is relatively high. In addition, the tunnel body passes through a moderately water-rich section, with a maximum water inflow of up to 20,462 cubic meters per day, equivalent to the storage capacity of 12 standard swimming pools. Along the route are distributed a national-level forest park and a first-class water source protection area, so environmental protection requirements are of a high grade and construction presents considerable difficulty.

It is understood that the Tianshui-Longnan Railway is a national railway Class I single-track railway in Gansu Province running from Tianshui City to Longnan City, and is also Gansu Province's first key railway project to be fully funded and independently built.