STV, in joint venture with Mott MacDonald, partnered with Sound Transit to deliver the Crosslake Connection, completing the final segment of the 2 Line across Lake Washington and enabling the world’s first light rail service to operate on a floating bridge. The seven‑mile extension travels along Interstate 90, directly linking Bellevue and Seattle while connecting the 2 Line with the 1 Line. With new stations at Mercer Island and Judkins Park, the Crosslake Connection expands regional mobility and forms part of a roughly 60‑mile light rail network stretching from Redmond through Seattle to Lynnwood and Federal Way. The project represents a historic milestone in passenger rail operations and regional transit connectivity.
What challenges did STV address?
The project introduced light rail operations to an unprecedented operating environment: a floating bridge spanning Lake Washington. Delivering safe, reliable rail service in this setting required careful coordination, extensive testing and precise integration of complex systems within an active interstate corridor.
What solutions did STV deliver?
Serving as systems construction management partner, STV worked in collaboration with Mott MacDonald through the Northwest Transit Systems Partners joint venture. STV’s engineers and inspectors oversaw the installation and testing of the overhead contact system, signaling, and communications systems to support reliable passenger rail operations across the floating I‑90 bridge.
How does this project benefit the regional transportation?
The Crosslake Connection strengthens regional mobility by directly connecting Seattle and the Eastside by light rail, expanding access to jobs, education and services while completing a critical link in Sound Transit’s expanding regional network.
Key stats and accolades
- World’s first light rail service operating on a floating bridge
- Final segment completing Sound Transit’s 2 Line across Lake Washington
- Seven‑mile light rail extension along Interstate 90
- New stations at Mercer Island and Judkins Park
- Direct light rail connection between Seattle and Bellevue
- Connects Sound Transit’s 2 Line with the 1 Line
