Sound Transit seeks feedback on Sounder South expansion

Longer trains, adding trips under consideration on Seattle to Lakewood route

Sound Transit wants feedback about its draft plan to expand capacity on the Sounder South train line.

A online open house of a draft Strategic Development and Implementation Plan is available through Feb. 6 at soundtransit.org/sounder-capacity. Sounder South runs between Seattle and Lakewood with stops in Tukwila, Kent, Auburn, Sumner, Puyallup and Tacoma.

The Sound Transit 3 (ST3) measure approved by voters in 2016 provided funding for capital improvements on Sounder South. To meet growing demand over the next decade Sound Transit is considering lengthening trains and platforms to carry up to 40 percent more passengers; potentially adding weekday trips and station improvements to accommodate longer trains and more riders.

In addition to investments in capacity expansion, the agency plans to extend Sounder service to Tillicum and DuPont by 2036.

The first step is to create a strategic plan to define which expansion projects best support anticipated ridership growth and meet the agency’s future capacity needs. The Sound Transit Board of Directors will initiate planning for the first round of projects this spring. Sound Transit estimates completing all expansion improvements by 2036.

Sounder has provided reliable, traffic-free service for Puget Sound residents for nearly 20 years. As highway congestion has more than doubled across the region, commuters are looking for other transportation options. That’s why Sounder South ridership has grown nearly 30% since 2014, according to Sound Transit. During the peak commute, each train carries an average of 875 passengers.

Visitors to the fall online open house and drop-in sessions were asked for feedback about their priorities for expanding Sounder South capacity. Read details about what Sound Transit heard in the outreach summary of the draft report. The agency also heard questions from residents about reliability, amenities on trains, service frequency and parking. For responses to these topics, view the Frequently Asked Questions.

For each improvement, Sound Transit will conduct project-level planning and environmental review with partners, stakeholders, tribes and host jurisdictions to measure and mitigate potential impacts. The agency will initiate the improvements on a rolling basis starting later this year.