World's Longest Underwater Rail Tunnel Driven

A shield tunneling machine developed by China, named Linghang, has set a world record by completing an 11.325-kilometer continuous underwater drive beneath the Yangtze River. This significant engineering feat enables high-speed trains to traverse the river at a remarkable 350 kilometers per hour without needing to reduce speed. The tunnel is a crucial component of the planned Shanghai-Chongqing-Chengdu High-Speed Railway, a major east-west transportation artery.

The Linghang machine, boasting a 15.4-meter ultra-large cutterhead and weighing approximately 4,000 metric tons, operated as a mobile underground factory. It bored through the riverbed while simultaneously constructing the tunnel lining. Engineers overcame immense challenges posed by the river's unstable strata and extreme hydrostatic pressure, maintaining millimeter-level alignment precision.

Once fully constructed by the end of this year, the tunnel will finally connect Chongming Island to the high-speed rail network. Travel time from Chongming to Shanghai's Baoshan Railway Station will be reduced to a mere 17 minutes, a stark contrast to the current two-hour road journey. This enhancement is expected to boost regional connectivity significantly.

Construction meticulously managed navigation routes, flood-control systems, and the Yangtze's delicate ecosystem. A fully enclosed slurry system was employed to manage muck and turbid water, minimizing disturbance to aquatic life. The project's completion by the year's end is highly anticipated.