China's Mega Shield Tunneling Machine Crosses Yangtze River for High-Speed Rail Project

On July 30, 2026, China's self-developed tunnel boring machine (TBM), 'Linghang'—reported as the world's largest diameter TBM for high-speed railways—successfully completed its underwater crossing of the Yangtze River. This milestone marks the structural completion of the aquatic section of the Chongtai Yangtze River Tunnel. Once fully finished and operational, the tunnel will connect Chongming Island, China's third-largest island, to the national high-speed rail network for the first time.

The successful water-crossing of the Chongtai Yangtze River Tunnel demonstrates China's advancing capabilities in manufacturing large-scale tunnel boring equipment and undertaking complex underwater civil engineering projects. Connecting Chongming Island to the high-speed rail grid will significantly enhance regional connectivity and integration within the Yangtze River Delta.

China reached a major civil engineering milestone on July 30, 2026, when its domestically developed shield tunneling machine successfully completed its drive beneath the Yangtze River, according to a report by People's Daily. The machine, named "Linghang," completed the underwater portion of the Chongtai Yangtze River Tunnel, marking the structural breakthrough of the project's most technically demanding aquatic segment. Described as the world's largest diameter high-speed railway tunnel boring machine (TBM), "Linghang" was built to navigate the complex hydrogeological environment under the lower Yangtze River. The successful completion of this underwater drive demonstrates the progress of China's high-speed railway construction capabilities under challenging riverbed conditions, where high water pressure and soft alluvial soil layers present severe engineering hurdles. Once the entire project is completed and opened to traffic, the Chongtai Yangtze River Tunnel will formally end the history of Chongming Island—China's third-largest island—lacking access to the national high-speed railway network. Currently, transportation to and from Chongming Island relies on roadway bridges, automotive tunnels, and ferry services. Integrating the island directly into the high-speed rail corridor is expected to greatly improve travel conditions for local residents and enhance regional mobility. The achievement also reflects China's strategy to push the boundaries of heavy equipment manufacturing. In developing large-diameter shield tunneling machines independently, domestic manufacturers aim to satisfy the demand for complex underground and underwater infrastructure projects across the country. Such mega-equipment is essential for driving major transport corridors through complex geographical barriers without disrupting surface navigation or environmental ecosystems. Despite the breakthrough beneath the Yangtze River, additional construction phases must be finished before trains can begin running. Engineering teams will now turn their attention toward completing the remaining onshore tunnel segments, which will be followed by ballastless track laying, power supply installation, and signal testing. Official reports have not yet provided a comprehensive operational schedule or a firm opening date for passenger service.