Floating Light Rail Bridge Crossing Marks Historic Moment for Seattle Transit

Once testing is complete, Sound Transit will open the world’s first light rail line that uses a floating bridge connecting downtown Seattle to the Eastside.

1 minute read

September 17, 2025, 8:00 AM PDT

By Diana Ionescu @aworkoffiction


White and blue Sound Transit light rail train on floating brige.

A Sound Transit light rail train passes over the floating bridge. | Sound Transit / The Platform

A Link light rail train crossed a floating bridge in Seattle using its own power last week, marking a historic first, according to a report from KOMO News. The test paves the way for more testing in the lead-up to the opening of the 2 Line Eastside extension in 2026. “The highly anticipated 2 Line crossing Lake Washington will connect the Eastside to downtown Seattle.”

A press release from Sound Transit notes, “Another unique element is that the floating bridge segment isn’t new; it’s been in service for many years, first as the I-90 express lanes, and now being converted for light rail trains. As many of you may know, WSDOT oversees the floating bridge, and they’ve been our project partners from the start. Our two agencies are coordinating closely to get the bridge ready for train traffic together — ensuring that the mix of old and new systems work together as intended, including tunnel ventilation fans, electric current isolation systems, and much more.”

This is “the first time in the world trains under power are operating across a floating bridge,” say Sound Transit officials. “The train traversed Lake Washington on the Homer M. Hadley bridge multiple times, gradually increasing its speed from approximately 5 miles per hour to the full operating speed of 55 mph, according to Sound Transit.”

Wednesday, September 10, 2025 in KOMO News

Young Professional

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban and Environmental Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban and Environmental Planner

Get top-rated, practical training for planners

"Planetizen federal action tracker" logo superimposed over black and white image of US Capitol dome.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

October 28, 2026 - Zachary Whalen

A car drives through a puddle, making a large splash. Rain pours down.

California plans to bury El Niño’s downpour

If the state plays its cards right, it may be able to store a billion acre-feet of El Niño’s water in aquifers.

October 28, 2026 - Grist

A pencil rendering of Foundry Park, which shows skyscrapers and public green spaces.

Chicago breaks ground on $3 billion megadevelopment

The new neighborhood, titled Foundry Park, will one day host 3,700 residences.

October 23, 2026 - Chicago Sun Times

A rendering of a high speed rain station in California, with wide platforms and a sleep train with yellow highlights.

California High-Speed Rail Authority CEO resigns after $600,000 scandal

Under Ian Choudri, the authority used taxpayer dollars to fund first class flights and trips to nightclubs.

October 30 - Cal Matters

 A bridge stretches across the Missouri River at Chamberlain, South Dakota.

Want to study the Missouri River? Soon, you may need unanimous approval from 10 states

Legislation would require 10 governors’ permission to study or build projects moving water outside the basin.

October 30 - South Dakota Searchlight

Lake Powell with much of the water evaporated.

Desperate measures: Advocates weigh draining Lake Powell to fill Colorado River

Draining the reservoir could reduce evaporation losses by a couple hundred thousand acre-feet.

October 30 - Yale Environment 360