[New progress in the world's longest undersea high-speed rail tunnel. All prefecture-level cities in the Yangtze River Delta will be connected to railways] On November 11, the world's longest undersea high-speed rail tunnel, the Jintang Undersea Tunnel of the Yongzhou-Zhou Railway, ushered in a critical node. The "Dinghai" shield machine on the Zhoushan side was nearly 80 meters underwater and was the first to reach the sea docking point and successfully completed the 6,270-meter single-head tunnel. According to reports, as a controlled project of the Ningbo-Zhou Railway, the Jintang Undersea Tunnel will be completed in 2027. After the project is completed and put into operation, the Yangtze River Delta will enter a new stage in which all prefecture-level cities are connected to railways.