When we last checked in on the East Link tunnel in Bellevue—which, come 2023, will carry light rail passengers from Seattle to the Eastside—back in October, 700 feet of the 1,985-foot corridor had been completed. In late June, Sound Transit announced that the job is 90 percent done. A Sound Transit spokesperson told Curbed Seattle that the job is expected to be completed by the end of next week.
The tunnel, which is 12 to 30 feet below Bellevue’s surface, isn’t being dug by a boring machine, like Bertha, or cut-and-cover. Instead, Sound Transit crews are using sequential excavation method (SEM), which removes small amounts of soil at a time with an excavator and iron girders. As the soil is removed, concrete is sprayed along the tunnel’s edge. Then crews continue lining the tunnel with support equipment and concrete.
A video from late June—available here—but tunnel nerds that want a peek at the excavation process can watch yet another video below.
When the line’s completed, the East Link train will start at the International District Chinatown station, then cross Lake Washington over Interstate 90. You can watch an animation of the train’s entire route on Sound Transit’s website.
In 2024, a year after the first stretch opens, the line is scheduled almost another four miles to southeast and downtown Redmond.