The first of two tunnel boring machines (TBM) that will dig Sound Transit's new twin light-rail tunnels from the Northgate neighborhood in Seattle to the University of Washington (UW) began mining July 9.
“It’s great to see these machines going underground,” said Sound Transit Board Chair and King County Executive Dow Constantine. “It will be even better when their job is finished and millions of light-rail riders will sail past one of the biggest traffic bottlenecks in the state.”
The machine will mine approximately 3.5 miles from the tunnel portal just south of the Northgate Transit Center to UW where the tunnels will connect with the University Link line into downtown Seattle. That section between downtown and the UW is scheduled to open in early 2016.
The $2.1-billion Northgate extension includes underground stations in the U District and Roosevelt neighborhoods and an elevated station at Northgate. The line will add major new capacity to the region’s transportation system, offering fast, frequent and congestion-free service 20 hours a day. A trip from Northgate to downtown will take 14 minutes. Northgate to UW Station will take eight minutes. The Northgate extension is expected to add more than 60,000 riders a day to the system by 2030.
These tunnels are being constructed by the same contractors, Jay Dee Contractors of Livonia, Mich., Frank Coluccio Construction Company of Seattle and Michaels Corporation of Brownsville, Wis., that completed two one-mile tunnels for the University Link light-rail project. The University Link light-rail project is currently scheduled to open in the first quarter of 2016, six to nine months early and is estimated to be completed approximately $150 million under budget.
A second TBM is being assembled at the Northgate site and is expected to begin mining the second tunnel in October.