Sound Transit outlines March 28 opening for Cross Lake connection; highlights operations, safety and community events for Mercer Island station

Sound Transit officials told the Mercer Island City Council on Feb. 3 that the agency is on track to open the Cross Lake connection on March 28, a milestone they said will link the 2 line to the 1 line and expand service from a 10-mile corridor to more than 30 miles running between Downtown Redmond and Downtown Lynnwood.

Dow Constantine, chief executive officer of Sound Transit, said the extension will "instantly transform" the 2 line and will provide Mercer Island riders with frequent service, connections to Bellevue, Redmond and Seattle and direct access to Sea-Tac Airport via transfers. "We're less than 8 weeks away from a truly historic day for our region and for Mercer Island in particular," he said.

Why it matters: the Cross Lake connection is the first light-rail deployment on a floating bridge and will change how people travel across Lake Washington by adding frequent, traffic-free rail service and new regional connections.

Engineering and testing: project engineers described multiple design adaptations needed for a floating-bridge alignment, including lighter rail, roughly 9,000 concrete plinth blocks and a system of eight "track bridges" to distribute movement. John Slavin, a civil engineer who worked on the project, said the design addresses three main technical challenges—weight limits on the bridge, electrical stray-current risk and movement/flexion of the rails—and that full-scale testing with thousands of sensors showed the solutions worked.

Operations and access: Sound Transit said 2 line trains will run every 8 to 10 minutes during much of the day, with even headways at junctions after the 2 and 1 lines merge. Brian Duplace, the agency's executive director of security and fare engagement, said service will run approximately 5 a.m. to 1 a.m., seven days a week, and that stations will be ADA accessible. He told councilmembers that roughly 4,000 parking stalls serve the entire 2 line and that Mercer Island station will include about 450 stalls; the agency said it aims to capture riders upstream at larger park-and-rides to reduce island parking demand.

Safety and staffing: Duplace and other staff outlined frontline staffing plans that include fare ambassadors, contracted law-enforcement support from the King County Sheriff's Office and a 24/7 security operations center. He recommended the public use the agency's "see something, say something" text line (206-398-5268) to report incidents; staff said security officers are stationed at each station and rotate onto trains as needed.

Opening-day planning and community events: Sound Transit's community-event model pairs the agency with a local 501(c)(3) to plan station activations, vendors, music and community portraits at new stations. Staff said they have already begun coordinating with Mercer Island city staff and the chamber to plan activations and potential shuttle connections to manage demand on the ribbon-cutting day.

Council concerns and follow-ups: councilmembers pressed on interoperability among jurisdictions for large incidents, the quantity of station parking and how to prioritize island residents' access. Sound Transit said it conducts joint training and drills with local emergency responders and that station-access plans (including potential shuttle service and bike facilities) will be refined with King County Metro and local partners. Officials agreed to follow up with per-station ridership estimates and to refine parking and shuttle plans ahead of the opening.

Next steps: Sound Transit and Mercer Island staff will continue coordination on public-safety training, station activations and last-mile access as the March 28 opening approaches.