China has completed the underwater section of the Chuntai railway tunnel beneath the Yangtze River, setting a world record for the longest continuous underwater boring operation on a high-speed rail project.
The tunnel boring machine, named Linghang, meaning Navigator, drilled 11.325 kilometers under the riverbed without interruption. The machine weighs 4,000 tons and has a cutting head 15.4 meters in diameter, making it the largest of its kind built for high-speed rail tunnels.
The tunnel reaches 89 meters below the surface, where water pressure hits 0.9 megapascals. Engineers relied on digital twin technology and intelligent geological forecasting to push through the soft sand and silt beneath the river, avoiding the need for intermediate construction shafts.
Once the line opens, trains will connect Chongming Island to Shanghai’s Baoshan station in 17 minutes at a top design speed of 350 kilometers per hour. The tunnel forms part of the Shanghai-Chongqing-Chengdu high-speed railway.
