A machine called Yongzhou is digging a train tunnel under the sea in China. The machine is 442 feet long. Engineers control it from a center about two miles away. Cameras and tools check its work and send warnings. Workers also stay on the machine to watch its work.
The machine has dug more than 4,000 meters from Ningbo. It has finished about 83 percent of its planned digging. It is moving toward an area 93 meters below the sea floor. Engineers expect it to reach the deepest part by the end of 2026.
The ground has hard rock and soft soil. These make digging difficult. Workers have changed about 4,000 cutting parts so far. To fix the machine, workers live in a special room with air under high pressure. They can stay there for up to 28 days and take turns working.
The Jintang tunnel will connect Ningbo and Zhoushan. It is about 10 miles long. The railway is expected to open in 2028 and bring train service to Zhoushan. The fast train trip between the two cities will take 26 minutes.
