Published on March 13, 2011 by NewsDesk - iWireNews ™ (iWireNews ™ and OfficialWire) GUANGZHOU (CHINA) OfficialWire News Bureau China announced Saturday it has completed a tunnel for the world's speediest trains underwater. The 6.7-mile Shiziyang Tunnel passes 200 feet under the Pearl River estuary in south China's Guangdong province, Xinhua reported. It is designed for trains traveling 220 miles per hour. The tunnel, China's longest, is part of an 87-mile high-speed rail link from Guangzhou to the major industrial city of Shenzhen and on to Hong Kong. Project manager Liu Guangjun said construction began in November 2007, and the rail link is scheduled to go into operation next year, cutting travel time between Guangzhou and Hong Kong from the current 2 hours to 40 minutes. The train ride to Hong Kong from Beijing will be cut to 8 hours.