Sound Transit opens light-rail extension to Northgate

Sound Transit explains the opening of Line 1 “heralds the start of an unprecedented period of transit expansion in the region. In just three years, the Link light-rail network will nearly triple in reach, from 22 miles to 62 miles, with service to Tacoma’s Hilltop in 2022, East King County in 2023 and Lynnwood, Federal Way and Downtown Redmond in 2024.”

Sound Transit Board Chair and University Place Council Member Kent Keel called the opening of the project a “historic day” and the beginning “of three years that will transform how people get around our region.”

"The opening of Northgate Link is a great leap forward for Puget Sound commuters, the first of many leaps forward for Sound Transit in the coming years," said Sound Transit CEO Peter Rogoff. "As Sound Transit looks to nearly triple our light-rail network in just the next three years, we are thankful for the hard work and dedication of staff and the construction workforce in achieving this monumental feat in the middle of a pandemic."

The project was part of the voter-approved Sound Transit 2 ballot measure in 2008 with construction beginning in 2012. The project includes 3.5 miles of twin tunnels that were bored starting in 2014. Boring of the tunnels was completed in 2016, guideway construction was completed in 2018, followed by rail installation in 2019. The extension’s stations reached substantial completion in 2021 and test trains have been operating since August 2021.

Sound Transit recognizes the multiple contractors worked on the project. Tunneling work was performed by JCM Northlink, a joint venture formed by Jay Dee Contractors, Frank Collucio Construction Company and Michaels Corporation. Hoffmann Construction was the contractor for the University District and Roosevelt stations, while Absher Construction was the contractor for Northgate Station. Stacy and Witbeck was the contractor for trackwork, and Mass Electric was the contractor for systems.

One particular engineering challenge faced was the requirement to minimize noise and vibrations of light-rail operations as they passed under University of Washington research buildings, which house highly sensitive equipment, not to mention billions in research.

The solution was floating slap track and ultra-straight rails. Tracks sit on 1,600 extra-dense concrete slabs reinforced with steel rebar. The concrete used is a mixture of hematite, known for its energy absorbing qualities, and custom-built rubber pads support each slab. Sound Transit reports the combination of the floating slab and rail have proven to absorb the vibrations caused by rail operations. The transit agency says every train is recorded by 40 monitors at 300-foot intervals and testing in the area confirms light-rail operations are meeting the criteria for quiet operations.

Engineering feats are not the only bit of bragging rights Sound Transit can claim with the project. On the financial front, the project was delivered for approximately $50 million under budget. The project’s $1.9 billion baseline budget includes a $615 million credit agreement under the Transportation Infrastructure Finance and Innovation Act (TIFIA), which provided significant long-term savings for regional taxpayers through reduced borrowing costs.

"The opening of the Northgate Link Extension will vastly improve travel between North Seattle and downtown," said Federal Transit Administration Administrator Nuria Fernandez. "With a seamless connection to the rest of the Link network, more people can easily reach jobs, schools and other opportunities throughout the region and replace sitting in traffic with safe, fast and efficient light-rail service."