The China Railway Design Corp announced on Thursday that its Tunnel Boring Machine has already dug a 3,000-meter section of the Zhanjiang Bay undersea tunnel, some 1,600 meters of which runs under the seabed, marking an important stage in the construction of the Guangzhou-Zhanjiang high-speed railway.The 9,640-meter tunnel is a key part of the line.The TBM can excavate at a speed of about 10 to 12 meters a day, with a record of 18 meters per day.Construction on the 401-km line, with a designated speed of 350 kilometers per hour, started in 2019 and is expected to be completed in 2024.The China Railway Design Corp announced on Thursday that its Tunnel Boring Machine has already dug a 3,000-meter section of the Zhanjiang Bay undersea tunnel, some 1,600 meters of which runs under the seabed, marking an important stage in the construction of the Guangzhou-Zhanjiang high-speed railway.The 9,640-meter tunnel is a key part of the line.The TBM can excavate at a speed of about 10 to 12 meters a day, with a record of 18 meters per day.Construction on the 401-km line, with a designated speed of 350 kilometers per hour, started in 2019 and is expected to be completed in 2024.