A worker screws a bolt tight at the construction site of the Chongming-Taicang tunnel, part of the Shanghai-Chongqing-Chengdu High-Speed Railway, under Yangtze River, on Dec. 16, 2025. The ongoing excavation of the tunnel under Yangtze River, carried out by the world's largest diameter high-speed rail shield tunneling machine the "Linghang" that is independently developed by China, has exceeded the 10,000-meter mark on Tuesday, which laid a solid foundation for the completion of the tunnel.

The 14.25 km single-hole double-track tunnel starts from Chongming of east China's Shanghai Municipality to Taicang in east China's Jiangsu Province, with the rail designed speed of 350 kilometers per hour. (Xinhua/Fang Zhe)