Shilin Tunnel is located at the section between Mile Station and Banqiao Station. The 18,208-meter tunnel is the longest one-portal double-track tunnel in China and the world's longest karst tunnel by drill and blast construction. The maximum depth of the tunnel is approximately about 250 meters. It started in August 2010 and is under construction at present. It is complex in geology, crossing six faults and four fracture zones, and is located at the watery block in Mile City, which make it a level I risky tunnel. The five R&D or improvement achievements of the project were awarded the national utility model patent certificates, namely, “Dryer Spin Network Supporting Structure”, “Hot Melt Welding Machine with Sealing Belt”, “Wind Separation Deduster”, “Multifunctional Monitoring and Measuring Pile of Tunnel”, and “Ultrasonic Welding Drill”. 

Shilin Tunnel of Nanning-Kunming Railway