Seattle will no longer be a one tunnel-boring machine town. While Bertha, the massive rig digging the Highway 99 tunnel sat idle under downtown in recent months awaiting repairs, a Sound Transit contractor has been quietly assembling a similar but smaller machine, which will soon begin tunneling at the north end of the city.
Unlike the oh-so-much-better-known Bertha, the machine on the Sound Transit job comes with a proven track record, having successfully completed other digs for the agency in recent years. The new Sound Transit project, known as the Northgate Link Extension, involves digging twin, 3.4-mile light rail tunnels beginning near NE 94th Street and First Avenue NE, and ending at University of Washington’s Husky Stadium. “Brenda,” the first machine set to launch, is scheduled to start mining in June. Another machine, known for now as TBM 2, is slated to begin digging the second of the twin tunnels sometime around October.