Seattle’s Floating LRT Bridge (Mother Nature)

Seattle is topping one of its famous floating bridges with light rail. Her trio of floating bridges are already a marvel of modern engineering. By 2023, one of these spans will be reconfigured to include a major rapid transit line.

As if it weren’t enough for the state of Washington to claim bragging rights as the self-described “floating bridge capital of the world”, transportation officials are beginning preparations to top one of these iconic pontoon-supported spans with a light rail line.

When complete, this huge — in both ambition and innovation — mass transit project will carry Sound Transit’s upcoming East Link Extension light rail line across Lake Washington, connecting Seattle to the cities of Bellevue and Redmond along with other well-heeled suburbs located on the lake’s eastern shores.

A city wedged in between two large bodies of water, Seattle is home to three of the world’s five longest floating bridges. All of them span Lake Washington, a freshwater ribbon lake that, along with the Puget Sound to the west, gives Seattle its isthmian character.

The Evergreen Point Floating Bridge, which carries State Route 520 over Lake Washington, is the world’s longest at 7,710 feet. Located to the south are the Lacey V. Murrow Memorial Bridge (6,620 feet) and the Homer M. Hadley Memorial Bridge (5,811 feet) — the world’s second and fifth longest floating bridges, respectively. These two bridges are often referred to singularly as the I-90 Floating Bridge as they run directly parallel to each other, carrying traffic eastbound (the Lacey V. Murrow Memorial Bridge) and westbound (the Homer M. Hadley Memorial Bridge) along Interstate 90 from Seattle to Mercer Island. Connecting the Olympic and Kitsap Peninsulas, the world’s third largest floating bridge, the Hood Canal Bridge, is located two hours northwest of Seattle.

It’s the shortest (but also the widest) of Seattle’s floating bridges — the Homer M. Hadley Memorial Bridge — that, by 2023, will be home to the world’s first-ever floating light rail line. The rail line itself will replace the bridge’s two reversible HOV “express” lanes that carry traffic westbound, toward Seattle, in the morning and eastbound, away from the city, in the evening.

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