The Yiwan railway, which spans from Yichang, Hubei Province to Wanzhou, Chongqin, known as “The Top Hard Construction Railway of the World,” was officially opened on December 22, 2010.

The success owes a lot to the core patent technology of independent R&D. Railway mapping reveals that the working sections of Yiwan railway are mostly located in the Karst mountainous area. Construction took 7 years, and the length of bridges and tunnels alone span an estimated 278km to 377km, accounting for 74% of the entire railway. During construction, Chinese technical personnel pioneered water and mud burst warning system, a hydrologic monitoring system for the complicated Karst tunnels and employed other innovative techniques; most of which now have filed invention patents applications.