The transformative Northgate Link Extension is a cornerstone of Sound Transit’s 25‑year regional expansion plan, connecting the University of Washington at Husky Stadium to the University District and the Northgate neighborhood. Spanning 4.3 miles, the line adds three new stations – two underground at U District and Roosevelt, and one elevated at Northgate – offering congestion‑free travel between Northgate and downtown Seattle in just 14 minutes, and a swift 47‑minute connection to Sea‑Tac Airport. By 2030, the extension is expected to serve more than 60,000 weekday riders, strengthening the Puget Sound region’s high-capacity transit network.
What challenges did STV address?
Expanding light‑rail capacity through dense urban neighborhoods required complex tunnel operations, systems coordination and construction in areas with significant ridership demand. Sound Transit needed an integrated systems partner capable of verifying that traction power, signaling, train control and communications functioned seamlessly across new tunnels, stations and operating environments.
What solutions did STV deliver?
As part of Northwest Transit Systems Partners – a joint venture with Mott MacDonald – STV managed systems construction for the extension. The team delivered technical review, construction management, quality assurance and inspections for traction power, communications, signaling and train control systems. These services ensured safe, reliable train operations through twin tunnels and new stations, providing riders with a smooth, dependable light‑rail experience.
How does this project benefit the region?
The extension reduces congestion, increases transit reliability and expands access to jobs, education and services throughout Seattle. It serves as a catalyst in Sound Transit’s broader expansion strategy, helping triple the region’s light‑rail system from 22 to 62 miles by 2024 and strengthening sustainable mobility across Puget Sound communities.
Key stats and accolades
- 4.3‑mile extension
- 3 new stations (2 underground, 1 elevated)
- 14‑minute travel time between Northgate and Downtown Seattle
- 60,000+ projected weekday riders by 2030
