[1] Construction of light rail was originally proposed in the 1996 Sound Move measure, with plans to open a line from Seattle–Tacoma International Airport to the University District in 2006.

[4] However, Sound Transit in the 1990s was plagued with continually escalating costs, include an agreement with the University of Washington to install dampeners on the rails that run under the science buildings, air cushions to tables in the science buildings, and to mitigate environmental impacts due to construction and traffic impacts from having the station on university grounds.

[5] In 1999, Sound Transit chose their preferred route for the light rail system, including a 4.5-mile-long (7.2 km) tunnel between downtown, First Hill, Capitol Hill and the University District with a crossing under Portage Bay;[6] the tunnel under Portage Bay was later deemed too costly and risky in 2000, and later dropped in favor of alternative options crossing the Montlake Cut.

[8] In 2004, Sound Transit selected a route for tunneled light rail extensions through Capitol Hill and the University District and towards Northgate, using the Montlake Cut and a new station at Husky Stadium.

[11] During a visit in November 2006 by Transportation Secretary Mary Peters and Senator Patty Murray, it was announced that the line had passed its third of four milestones to get the grant when it received federal approval to complete its final design.

[17][18] Two of the tunnel-boring machines, named "Balto" and "Togo", were manufactured by Herrenknecht in Germany and were launched from the University of Washington station south toward Capitol Hill; each machine weighed 1,109,900 pounds (503,400 kg) and were named after two famous Alaskan husky sled dogs from the 1925 serum run to Nome as a reference to the Washington Huskies athletic program.

The tunnel passes 15 feet (4.6 m) under the Montlake Cut while climbing a 4.5% grade to end at University of Washington station near Husky Stadium.