On December 10, the Chongqing–Kunming High-Speed Railway achieved a key breakthrough with the 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, staying on track for full line completion. | CGTN