DuPont Sounder Extension
Project map and summary
Project updates
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Overview
The DuPont Sounder Extension project will add S Line service south from Lakewood via two new stations at Tillicum and DuPont. The new stations will help provide service to Joint Base Lewis-McChord as well as to residents and businesses in south Pierce County.
Project timeline
In May 2026, the Sound Transit Board adopted an updated ST3 System Plan to bring the agency’s long-term financial outlook into balance.
The plan includes funding for DuPont Sounder Extension project planning.
Final design and construction of the extension — as well as its associated parking facilities — are not currently funded in the agency’s Long-Range Financial Plan.
Early planning and design work for the DuPont Sounder Extension will launch in 2027. This work includes:
- Assessing potential alternatives to the representative investments identified in the voter-approved ST3 Plan.
- Identifying ways to potentially accelerate the project timeline through innovative project delivery methods, approaches, and financing strategies.
The Sound Transit Board will evaluate options for restoring additional funding for partially funded projects as cost and revenue uncertainties are resolved. Projects in this category will be allocated funding based on available agency capacity and subarea finances at the time resources become available.
You can learn more about capital project development phases here.