BEIJING, Dec. 17 (Xinhua) -- China's domestically developed, world's largest-diameter high-speed-rail shield tunneling machine "Linghang" surpassed the 10,000-meter mark on Tuesday, leaving just 1,000 meters to reach the south bank of the Yangtze River.

Boring an underwater tunnel linking Shanghai's Chongming District and Taicang City in east China's Jiangsu Province, the shield machine measures 148 meters in length, weighs around 4,000 tonnes, and is equipped with the world's largest cutter head, spanning 15.4 meters in diameter, the Science and Technology Daily reported Wednesday.

It is also equipped with intelligent sensing, excavation and lining-erection systems.

The Chongming-Taicang Yangtze River tunnel runs 14.25 km in total, with 13.2 km planned for boring. Once operational, it will allow high-speed trains to pass beneath the Yangtze without reducing speed.

This latest tunneling marks a major phased breakthrough for the world-class Yangtze-crossing tunnel and lays a solid foundation for the completion of the entire line.  ■