Wedoany.com Report-Apr. 18, The world’s largest shield machine for railway construction reached the midpoint of its underwater journey beneath the Yangtze River, advancing the high-speed rail tunnel connecting Shanghai’s Chongming Island to Taicang, Jiangsu province on Wednesday. This milestone marks significant progress for the Shanghai-Nanjing-Hefei high-speed railway project.

Developed in China, the 148-meter-long machine, with a 15.4-meter diameter, is operated by China Railway Tunnel Group Co. Named Linghang, or “Navigator,” it is currently 66 meters below the riverbed and is expected to reach its deepest point of 89 meters in approximately four months. Wang Yi, the project’s deputy equipment manager, noted: “With a gradual downward slope, the pressure from the surrounding water on the construction project is rising.” He added: “At that point, the water pressure will be 0.9 megapascal — as overwhelming as six people standing on a fingernail.”

Since beginning operations in April 2024, the machine has advanced 5,660 meters, completing 2,830 ring segments at a rate of 24 to 28 meters daily. The 14.25-kilometer tunnel, set to open by late 2029, will allow trains to travel at 350 kilometers per hour, the fastest for any underwater tunnel globally, matching surface speeds.

The project’s complexity challenges the shield machine’s capabilities. Wang explained: “To meet the demand, we use a main bearing with a service life of 16,700 hours, nearly triple the theoretical lifespan of similar components.” The machine features an “intelligent tunneling brain” system, enabling unmanned operations with staff only on duty. Wang said: “This project became the world’s first to achieve unmanned tunneling operations, with staff required only to be on duty.” The AI system supports nine functions, including perception, tunneling, and management, automating decision-making.

The tunnel has safely navigated six of 21 identified risk zones, including a highway and a protected aquatic farming area, according to Fu Bowei, deputy chief engineer. The project is a vital part of the Shanghai-Nanjing-Hefei railway, a segment of the broader Shanghai-Chongqing-Chengdu high-speed rail network, enhancing connectivity across the Yangtze River Delta.

Upon completion, the tunnel is expected to significantly shorten travel times between Shanghai, Nanjing, and Hefei, supporting regional economic integration and sustainable development in the Yangtze River Economic Belt.