China's self-developed "Linghang," the world's largest-diameter high-speed rail shield tunneling machine, has resumed tunneling after 41 days of maintenance. With a 15.4-meter cutter head and a weight of 4,000 tonnes, it is being used to excavate the land section of the Chongtai Yangtze River Tunnel. This project is expected to set a new world record for ultra-long single tunneling and is scheduled for completion by the end of 2026.