China's mega tunneling machine completes Yangtze River underwater tunnel breakthrough

This photo taken on July 30, 2026 shows a view of the shield tunneling machine "Linghang" at the construction site of the Chongming-Taicang Yangtze River tunnel under China's Yangtze River. China's domestically developed world's largest-diameter high-speed-rail shield tunneling machine "Linghang" completed tunneling of the underwater section of the Chongming-Taicang Yangtze River tunnel on Thursday. The milestone lays the foundation for China's first high-speed railway crossing beneath the Yangtze River at 350 kilometers per hour without slowing down. (Xinhua/Fang Zhe)

SHANGHAI, July 30 (Xinhua) -- The world's largest-diameter shield tunneling machine, tailored for high-speed railway projects and developed domestically in China, successfully holed through an underwater tunnel traversing the Yangtze River on Thursday.

The breakthrough will allow a high-speed train to run beneath the Yangtze River at a full speed of 350 km per hour without slowing down for the first time, marking a landmark progress in China's river-crossing railway tunneling technology.

With a total length of 14.25 kilometers, the tunnel connecting Shanghai's Chongming District and Taicang City in neighboring Jiangsu Province is built according to the highest construction standards among China's high-speed rail river-crossing projects, while ranking among the most technically challenging mega infrastructure works of its kind.

Li Bin, chief engineer of the tunnel project with China Railway Tunnel Group Co., Ltd., noted that the 148-meter-long shield machine weighs around 4,000 tonnes and features a 15.4-meter ultra-large cutter head, making it the world's largest-diameter tunneling equipment for high-speed railway construction.

The unmanned tunneling gear achieved a single continuous underwater drive of 11.325 kilometers under the Yangtze, setting a new domestic record for 15-meter-level shield tunneling.

The full completion of the entire tunnel is scheduled by the end of 2026. Once put into operation, the project will end the island district of Chongming's lack of high-speed rail access, and cut travel time from Chongming via Taicang to Shanghai's Baoshan Railway Station to just 17 minutes, significantly improving regional transportation connectivity. ■

This photo taken on July 30, 2026 shows a view of the shield tunneling machine "Linghang" at the construction site of the Chongming-Taicang Yangtze River tunnel under China's Yangtze River. China's domestically developed, world's largest-diameter high-speed-rail shield tunneling machine "Linghang" completed tunneling of the underwater section of the Chongming-Taicang Yangtze River tunnel on Thursday. The milestone lays the foundation for China's first high-speed railway crossing beneath the Yangtze River at 350 kilometers per hour without slowing down. (Xinhua/Chen Haoming)

This photo taken on July 30, 2026 shows a view of the shield tunneling machine "Linghang" at the construction site of the Chongming-Taicang Yangtze River tunnel under China's Yangtze River. China's domestically developed, world's largest-diameter high-speed-rail shield tunneling machine "Linghang" completed tunneling of the underwater section of the Chongming-Taicang Yangtze River tunnel on Thursday. The milestone lays the foundation for China's first high-speed railway crossing beneath the Yangtze River at 350 kilometers per hour without slowing down. (Xinhua/Chen Haoming)

A technician works at the construction site of the Chongming-Taicang Yangtze River tunnel under China's Yangtze River, July 30, 2026. China's domestically developed, world's largest-diameter high-speed-rail shield tunneling machine "Linghang" completed tunneling of the underwater section of the Chongming-Taicang Yangtze River tunnel on Thursday. The milestone lays the foundation for China's first high-speed railway crossing beneath the Yangtze River at 350 kilometers per hour without slowing down. (Xinhua/Chen Haoming)

This photo taken on July 30, 2026 shows an exterior view of the launch shaft for the shield tunneling machine "Linghang" of the Chongming-Taicang Yangtze River tunnel in Chongming District, east China's Shanghai. China's domestically developed, world's largest-diameter high-speed-rail shield tunneling machine "Linghang" completed tunneling of the underwater section of the Chongming-Taicang Yangtze River tunnel on Thursday. The milestone lays the foundation for China's first high-speed railway crossing beneath the Yangtze River at 350 kilometers per hour without slowing down. (Xinhua/Fang Zhe)