Sound Transit completes Northgate-Roosevelt LRT tunnel March 17, 2015 | North America News Seattle’s Sound Transit has completed the 2.4-km (1.5-mile) long Northgate-Roosevelt light-rail transit (LRT) tunnel as part of the 6.9-km (4.3-mile) Northgate Link extension. This is the first ... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password