Sound Transit briefed media on the installation of ballasted tracks that will carry light rail vehicles across Mercer Island on Dec. 18.
The mile-and-a-third-long segment, running from 80th Avenue Southeast to just east of East Mercer Way, will be the first segment of rail completed on the East Link project.
Contractor crews are installing rail on concrete ties set in large rocks, or “ballast,” which forms a bed for the track. The installation process for ballasted track starts with applying a rubberized material to the existing pavement known as a “ballast mat.” Crews then place an even layer of ballast along the ground where the tracks will be set.
Pre-fabricated concrete ties are evenly set on top of the ballast. Once the ties are set, crews thread long sections of steel rail through clips on each end of the ties. Then, crews “flood” the rail bed to bring the layer of ballast flush with the top of the ties. Finally, a machine called an automatic tamper rolls along the rails to precisely measure the height of the rail using a laser, and adjust the level of the ties and rails as necessary to maintain a consistent height.
In the coming year, crews will install rail on the Homer M. Hadley floating bridge, including the innovative track bridges that will accommodate lake motion to allow light rail vehicles to travel safely and reliably across the floating section of I-90.
East Link will extend light rail 14 miles from downtown Seattle to downtown Bellevue and the Overlake area of Redmond via Interstate 90, with 10 stations. Construction of the East Link extension is more than 40 percent complete, and the entire line will be operational in 2023. For more information on the East Link Extension see: www.soundtransit.org/Eastlink
Sound Transit is simultaneously working to extend light rail north, south, east and west, opening new stations every few years to form a 116-mile regional system by 2041. Starting in 2021 the Northgate project will provide reliable, congestion-free travel to Seattle’s University District, Roosevelt and Northgate neighborhoods. Northgate Link will be followed by the opening of service to Mercer Island, Bellevue and Redmond’s Overlake community in 2023. Additional extensions to Shoreline, Mountlake Terrace, Lynnwood, Kent/Des Moines, Federal Way and downtown Redmond are planned to start service in 2024. Further light rail extensions are scheduled to reach West Seattle, Fife and Tacoma in 2030; Ballard in 2035; Paine Field Industrial Center and Everett in 2036; and South Kirkland and Issaquah in 2041.
The agency is also working on further investments including, but not limited to, expansions of Sounder South service and bus rapid transit service in 2024 along the north, east and south sides of Lake Washington. More information is available at https://systemexpansion.soundtransit.org.