Hitachi Zosen unveils world's biggest shield tunneling machine

OSAKA, Japan - Hitachi Zosen Corp. shows to the press on Dec. 25, 2012, what it claims to be the world's largest shield tunneling machine at its Sakai plant in Osaka Prefecture. The 110-meter-long machine with a diameter of 17.45 meters and weighing some 7,000 tons will be used to drill a 2,800-meter tunnel in Seattle in the U.S. state of Washington to replace an aging elevated highway, the company said.