Tunnel FAQs

Header Image
Tunnel Construction Photo

The East Link tunnel, approximately 1/3 mile-long, will extend from Main Street at 112th Avenue SE (south portal) to NE 6th Street (north portal). The south portal of the tunnel is just north of the East Main station; the north portal is at the future Bellevue Downtown Station

Construction began in March 2016 with the removal of structures and vegetation along Main Street and 112th Avenue SE. Crews then began preparing the soil for tunneling activities at the north portal on 110th Ave NE between NE 4th and NE 6th Streets (by Bellevue City Hall). Sound walls were constructed in Sept. 2016 around the south portal area (Main Street/112th Avenue SE).

Tunnel excavation at the south portal began in Feb. 2017 and was completed in July 2018.

Construction of the tunnel is expected to be complete in the 2nd quarter of 2020.

Tunneling will be performed by Sequential Excavation Method (SEM) which involves digging out small sections of soil using an excavator and cutting equipment. As soon as soil is removed, pressurized concrete is sprayed on the tunnel’s sides, ceiling and floor. This tunneling method does not involve a tunnel boring machine. SEM minimizes impacts to surface streets, traffic and reduces noise and dust.

Watch a time lapse video of tunnel excavation (Aug. 2017)

Bellevue’s Noise Control Code (Noise Code) regulates and establishes permissible noise levels based on the type of land use (e.g. residential, business or commercial). The code also sets daytime noise levels in residential areas at a maximum of 55 dBA (decibel level) and nighttime (between 10 p.m. and 7 a.m.) at a maximum of 45 decibels.

Construction noise is allowed between 7 a.m. and 6 p.m., Monday through Friday and 9 a.m. to 6 p.m. on Saturday. Construction noise is prohibited beyond these hours, on Sunday, and on certain holidays, unless otherwise allowed by a city-approved permit. The Noise Code does contain exemption provisions.

For tunnel construction, the city approved an Expanded Exempt Work Hours permit (Permit 15-122917 LY) to allow for the continuous 24-hour cycle needed for sequential excavation (duration of permit 52 months).

  • Long-term closure at 110th Avenue NE in downtown Bellevue Beginning on Monday, April 16th, 2018, Sound Transit's contractor closed southbound 110th Avenue Northeast and the west sidewalk between Northeast 3rd Place and Northeast 2nd Place in preparation of excavation and construction of a tunnel ventilation and access shaft to the downtown Bellevue tunnel underneath the roadway. This is a long-term closure and is excepted to last until 2021.
  • As excavation continues at the south portal (Main St/112th Avenue SE), there will be intermittent lane closures for more utility work and for trucks hauling excavated dirt.
  • Some of the construction activities along 110th Avenue NE such as utilities, soil replacement, and monitoring equipment occurred in 2016 and early 2017.

As it relates to the East Link light rail project, mitigation is known as measures that are intended to lessen the impact of construction and operation of the trains.

Mitigation is a high priority for the city and Sound Transit and was addressed in the planning, design and construction of the light rail occurring in Bellevue.

View Mitigation Map (Jan. 2018)

The following are ways to receive East Link construction updates:

Sound Transit

  • Subscribe to receive updates via text or email
  • Contact the Outreach Office at 206-398-5465

City of Bellevue

  • Subscribe to receive updates via text or email
  • Contact Marie Jensen, East Link Outreach Lead at 425-452-2064

If you have a concern or question about light rail construction, please contact:

Sound Transit/East Link Outreach Office

  • 206-398-5465
  • eastlink@soundtransit.org
  • 1-888-298-2395 (24-hour construction hotline)

City of Bellevue

  • Marie Jensen, East Link Outreach, 425-452-2064 or mjensen@bellevuewa.gov
  • Submit a service request with the MyBellevue app