The East Link Extension is a planned Sound Transit Link Light Rail line, spanning about 22 miles from Downtown Seattle eastward to the city of Redmond. Funding for construction of the portion of East Link between Downtown Seattle and Overlake Transit Center was approved by voters in November 2008, while the final segment between Overlake Transit Center and Downtown Redmond was identified as a priority extension in a future expansion measure. Construction of East Link began in 2016, and the line is scheduled to open for service to Overlake in 2023.
The line will operate as the Blue Line when it opens in 2023, interlining with the Red Line from Northgate to International District/Chinatown.
On April 25, 2013, the Sound Transit board decided on a final route for East Link, traveling east from International District/Chinatown station in Seattle, across Lake Washington and Mercer Island, through Bellevue and Bel-Red to Overlake Transit Center in Redmond. Voters in Bellevue, Washington approved the Link light rail extension from Seattle, across Lake Washington on Interstate 90, through Bellevue and on to the Overlake Transit Center in Redmond. The project is currently in the final design phase, with construction scheduled to begin in 2015 and service expected to start in 2023. An estimated 50,000 passengers will use East Link every day by 2030.
From the International District/Chinatown Station, trains will travel on existing ramps to the Interstate 90 express lanes from the Downtown Seattle Transit Tunnel, possibly in mixed traffic with buses. Currently, the I-90 express lanes carry vehicle traffic (both single-occupancy vehicles and high-occupancy vehicles (HOV)), but will be modified to serve only trains, and an all-day HOV lane will be added to each direction of the I-90 bridge. The trains will use the center roadway from Seattle through the Mount Baker Tunnel, across Lake Washington on the Homer M. Hadley Memorial Bridge, under Aubrey Davis Park on Mercer Island, and on the East Channel Bridge to South Bellevue. Trains will turn and head north from I-90 along Bellevue Way and 112th, before cutting across to Main and I-405. In Downtown Bellevue, the trains will go through a tunnel underneath 110th, a plan that the board decided upon in July 2011. From there, trains will head east at NE 12th street past Overlake Hospital through the Bel-Red industrial area along NE 16th street. In the Overlake neighborhood, trains will connect with State Route 520 and head north towards Downtown Redmond and Redmond Town Center.