Seattle’s Light Rail Across Lake Washington Nears Service as Final Testing Advances
Sound Transit prepares for first passenger service over the I-90 floating bridge following historic powered rail trials and comprehensive integration tests
Sound Transit is preparing to complete a milestone expansion of Seattle’s light rail network with passenger service across Lake Washington expected before May 31, 2026, ushering in a transformative connection between Seattle and the Eastside communities of Bellevue, Mercer Island and Redmond.
The project’s centerpiece, the East Link Extension’s Crosslake Connection, includes the first light rail tracks ever installed on a floating bridge — the Homer M. Hadley portion of Interstate 90 — and has reached its final phases of system integration testing.
In September 2025, a fully electrified Link light rail vehicle became the first powered train in the world to cross a floating bridge under its own power, validating key systems for traction, communications and power delivery on a dynamic structure that moves with water level changes.
Sound Transit has continued to run live-wire tests with increasing frequency and train configurations to ensure the route is ready for passenger operations.
Construction and testing on the Lake Washington segment experienced delays from earlier schedule targets, pushing the expected opening into spring 2026 as Sound Transit works through technical challenges and final qualifications for operators and longer trains.
Officials say that daytime train movements over the bridge will soon become a familiar sight as part of “pre-revenue” trials that precede full public service, with the goal of opening the line ahead of major regional events such as the FIFA World Cup next summer.
The extension also includes new stations at Judkins Park in Seattle and Mercer Island, designed to serve residents on both sides of the lake.
Once operational, the linkage will integrate with existing segments of the Link system and significantly improve regional mobility, reducing travel times and offering a cleaner, more reliable alternative to road traffic across the water.
Sound Transit continues to refine service plans and train operations as the final testing phases progress toward the anticipated launch of passenger service in early 2026.
The project’s centerpiece, the East Link Extension’s Crosslake Connection, includes the first light rail tracks ever installed on a floating bridge — the Homer M. Hadley portion of Interstate 90 — and has reached its final phases of system integration testing.
In September 2025, a fully electrified Link light rail vehicle became the first powered train in the world to cross a floating bridge under its own power, validating key systems for traction, communications and power delivery on a dynamic structure that moves with water level changes.
Sound Transit has continued to run live-wire tests with increasing frequency and train configurations to ensure the route is ready for passenger operations.
Construction and testing on the Lake Washington segment experienced delays from earlier schedule targets, pushing the expected opening into spring 2026 as Sound Transit works through technical challenges and final qualifications for operators and longer trains.
Officials say that daytime train movements over the bridge will soon become a familiar sight as part of “pre-revenue” trials that precede full public service, with the goal of opening the line ahead of major regional events such as the FIFA World Cup next summer.
The extension also includes new stations at Judkins Park in Seattle and Mercer Island, designed to serve residents on both sides of the lake.
Once operational, the linkage will integrate with existing segments of the Link system and significantly improve regional mobility, reducing travel times and offering a cleaner, more reliable alternative to road traffic across the water.
Sound Transit continues to refine service plans and train operations as the final testing phases progress toward the anticipated launch of passenger service in early 2026.
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