Second tunnel boring machine completes underground trip to Capitol Hill

Publish Date

Video now online at Sound Transit website

The second tunnel boring machine mining new light rail tunnels between Capitol Hill and the University of Washington finished its underground journey Monday afternoon.

See video of the TBM holethrough here:

Sound Transit tunneling contractors Traylor Frontier-Kemper will now focus on building 15 cross passages between the two tunnels. A different contractor, JayDee Collucio Michaels joint venture, is scheduled to complete tunneling between Capitol Hill and downtown Seattle in June.

When complete, the University Link project will connect the UW and Capitol Hill to downtown Seattle with 3.1 miles of new underground light rail service.

The overall $1.9 billion project is about halfway complete and scheduled to open in 2016. The expansion with stations in the heart of Capitol Hill and the University of Washington will provide unparalleled speed and reliability through Seattle's most dense neighborhoods. A trip from Husky Stadium to Westlake will take six minutes and is expected to add 70,000 riders to the system by 2030.

The corridor includes three major universities /colleges - the University of Washington (UW), Seattle University, and Seattle Central Community College (SCCC) - with a combined enrollment of more than 50,000 students.

The contractor launched the TBM from the UW station site near Husky Stadium in June, 2011. The TBM passed beneath the Montlake Cut and Montlake, Interlake, Volunteer Park and north Capitol Hill neighborhoods.

Each of the UW to Capitol Hill TBMs:

  • Weighs over 1 million pounds
  • Stretches more than 500 feet long including the conveyor system that removes spoils from the cutterhead to the surface
  • Places 21' diameter pre-cast concrete tunnel liners as it mines through the earth
  • Was built in Germany especially for this job and assembled and tested at the Port of Tacoma