It's been two years since the Sound Transit light rail east link project started in 2019.
Crews have jumped so many hurdles, and the project is halfway done.
But the project initially had Washingtonians' eyebrows raised, because trains had to cross the I-90 floating bridge to go to mercer island.
Knowing the trains had to cross that floating bridge in the first place, many wondered, "but how?"
In an interview with K5 news, the deputy executive director of Sound Transit, John Sleavin, talked about the challenges that the crews were faced with.
(Link to the entire interview: https://www.youtube.com/watch?v=c91ba5ptKPs)
Designed to flex and twist in response to rising and falling lake levels, traffic, wind an waves, the I-90 bridge doesn't look sturdy. It's generally not a problem for vehicle traffic since there are gaps between bridge segments for expansion and contraction. But building a rail line on that bridge certainly entails more planning beforehand.
To cope with that problem, Sound Transit came up with an innovative method to overcome that particular challenge - a unique set of track bridges aimed at compensating for lake motion, allowing trains to glide safety along on level track. It's an innovative method, according to Sleavin. "We had to invent this system. This has never been done anywhere else in the world, where we have taken light rail from a fixed bridge onto a floating bridge." Said Sleavin.
With that unique system, Sound Transit assembled a mile-long section of its bridge track at a rail test facility in Colorado. "Steel can flex as long as you do it over a long enough distance." Said Sleavin.
To enable construction of the new rail route, Washington State's Department of Traffic permanently closed the I-90 express center traffic lanes two years ago, squeezing vehicles into existing roadways. HOV lanes were added in each direction.
Versatility is what Sound Transit's light rail is known for. Quick and comfortable, trains running on the new light rail line, named "the Blue Line", will carry commuters from Bellevue to downtown Seattle in just 24 minutes, Mercer Island to the University of Washington in 20 minutes, and South Bellevue to SeaTac airport in 50 minutes.
Slated to start service in 2023, the new rail line is expected to provide those living in Bellevue and Mercer Island with an alternate route for travel.
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