On December 10, the Chongqing-Kunming High-Speed Railway reached a major milestone with the successful drilling of the 24.8-kilometer Yiliang Tunnel – China's longest high-speed rail tunnel designed for 350 kilometers per hour travel. Cutting beneath the Wumeng Mountains with up to 920 meters of overburden, the project overcame rock bursts, high temperatures and soft-rock deformation, remaining on schedule for full line completion.