System expansion

Voters approved projects in 1996, 2008, and 2016. Sound Transit is building the most ambitious transit expansion in the country.

KEY

New service
Parking & access
Operations & maintenance facilities
Link light rail
Sounder rail
Stride bus rapid transit

Expansion projects

Regionwide updates 

Spring/Summer Progress Report 

Learn about the innovative Wind and Wave Monitoring System that supports 2 Line operations across the I-90 floating bridge, find everything you need to know to take advantage of transit for the region’s big “summer of soccer,” see what our new five-year Sustainability Plan means for you, and much more.  

Long-term affordability

Delivering the ST3 vision

Sound Transit is working to close a $34.5 billion future funding gap projected through 2046 to deliver what's outlined in the voter-approved Sound Transit 3 program. ST3 includes light rail extensions to West Seattle, Ballard, Tacoma, and Everett, new service between South Kirkland and Issaquah, and much more.

Learn about the Enterprise Initiative

Take our survey by May 1

Latest project updates

April 23, 2026
Lakewood Station Access Improvements

Topographical and utility locating survey work in Lakewood

April 23, 2026
South Tacoma Station Access Improvements

Topographical and utility locating survey work in South Tacoma

The Platform

The heart of Sound Transit’s mission is to provide the people of the Puget Sound region with an effective, affordable, and reliable public…
When the 2 Line Crosslake Connection opens on March 28, riders will not only experience a more connected region. Public art installations at the two…
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Latest project documents

Tacoma Dome Access Improvements

Public engagement summary - Tacoma Dome Access Improvements - Spring 2026

(PDF Document | 1MB) Updated 04/24/2026

Environmental, Operations and Maintenance Facility South

OMF South SEPA Addendum

(PDF Document | 38MB) Updated 04/23/2026
See all project documents
See all project documents