The world’s biggest tunnel boring machine, at 57.5 feet in diameter, is now being assembled by Hitachi-Zosen in Osaka, Japan, before being shipped to Seattle next year to drill the Highway 99 tunnel.
On Thursday night, the public can go on a 1-mile walking tour around the launch pit in Sodo. The tour begins at 6 p.m. at Milepost 31, the state’s tunnel interpretive center at 211 First Ave. S., which contains a 10-foot-long scale model of the boring machine.
More information can be found through the Milepost 31 website. Tunnel drilling begins in summer 2013, with the $2 billion, four-lane tube scheduled to handle traffic, at a yet-undetermined toll rate, by the end of 2015.