Sound Transit to overhaul ST3 program, what it could mean for Pierce County

It was a mixed bag of news from Sound Transit last week, with an announcement that light rail to Downtown Federal Way connecting to Seattle-Tacoma International Airport and Downtown Seattle would open on December 6th, 2025. This is good news for transit riders and urbanists in the South Puget Sound as light rail comes closer to fully serving South King County and Pierce County.

However, as Ryan Packer at the Urbanist writes, the Sound Transit Board approved Motion M2025-36, otherwise known as the "Enterprise Initiative" which seeks to conduct a major overhaul of the voter-approved ST3 program as well as Sound Transit's Long Range Plan, as it faces the twin constraints of inflation in construction costs and diminished projected tax revenues. The gaping budget hole of $20-$30bn means that projects that were previously considered settled and committed may turn out not to be. All we can be certain of at this juncture is that change to the plan is coming.

Up until now, Sound Transit has handled impacts to tax revenues or cost inflation by simply delaying construction timelines a few years or seeking modest adjustments to project scope. Tacoma Dome Link Extension for instance was originally slated to open as an extension of the 1-Line in 2030, and that timeline has been twice delayed to 2032 and now stands at 2035. The westward extension of the T-Line to Tacoma Community College has also shifted from 2039 to 2041, while the ST3 program overall is meant to be fully complete by 2045.

Generally this method of delaying projects has been the strategy because Sound Transit, while it collects taxes in perpetuity to construct and operate the regional transit system, is limited in the amount of debt service it can issue by the Washington State Constitution, which places a cap of debt at 1.5% of the property value in the Sound Transit District. Now it seems like that strategy can no longer support the program, especially as "bottom-up" cost estimates of aerial spans, tunneling, stations, vehicles, and maintenance facilities shows not just inflation-driven growth, but also scope-driven increases in project costs as we saw with West Seattle Link, coming in at a mind-blowing $7bn for four stations between Alaska Junction and SODO.

So what, if anything is going to change in Pierce County's part of the program? Well there are several buckets of projects that might be modified:

"Regional" projects

Let's look at the so-called regional projects that Pierce County is making some contributions to as a part of the ST3 program, and what I mean by regional are projects that support the overall network, but the investments themselves are not located in Pierce County.

One such investment is the OMF South light rail maintenance facility to support Tacoma Dome Link Extension. It's unlikely that project would be modified as the vehicle capacity is desperately needed to support the entire light rail system and is needed for the Tacoma Dome Link Extension to come online. Residents in Pierce County might be surprised to know that they are contributing some funds to support a second downtown transit tunnel in Seattle, which is slated to enable connections between Downtown Seattle, Seattle Center, Interbay and Ballard. Connecting Tacoma to those destinations on 1-Line is still a worthwhile goal, but is it still achievable?

Light rail - Tacoma Dome and TCC

Pierce County got two light rail extensions as a part of the ST3 program. The first is Tacoma Dome Link Extension or TDLE, which is roughly 10 miles long, has four planned stations at South Federal Way, Fife, Portland Avenue, and Tacoma Dome. Cost estimates for TDLE are between $4-$5bn with a final EIS to be published in 2027 and construction to start around 2030. It would be the first light rail line in the country to serve a tribal reservation. An elevated level of coordination has been crucial to secure the authority to traverse the sovereign territory of the Puyallup Tribe of Indians with special emphasis on issues related to crossing the Puyallup River. With so few stations on this line, prior commitments made to the Tribe, and substantial actions taken to pick the most cost effective station options from those analyzed--it is difficult to fathom how the scope of this extension could be diminished without substantially reducing its efficacy and value for the community. This segment of light rail will serve areas of the Sound Transit district that have less economic opportunity versus those with light rail access, such as Bellevue, Redmond, or Seattle.

The second light rail extension programmed in ST3 was the westward extension of light rail from the Downtown Tacoma Regional Growth Center to Tacoma Community College. This extension of surface rail, with seven new stations, includes a new maintenance facility for one-car light rail, as well as project elements for double-tracking that have constrained operations and led to impacts of service frequency and reliability since the line went into service in 2003. Costs are between $400-$500m in 2014, which could be closer to $1bn at current rates of inflation.

TCC Link extension has yet to go into federally-mandated alternatives analysis and is currently projected to come into service in 2041. Of all of the projects in the Pierce County portfolio, this is the one that may stand out as having the most potential for change. The corridor along South 19th Street, which is the representative alignment of the extension, has been of considerable interest to Pierce Transit for developing bus rapid transit and is recognized in the Pierce County Comprehensive Plan as potential bus rapid transit corridor. Add to that the Tacoma Transportation and Mobility Plan identifies that a study should be conducted to consider other viable alternatives for connecting to TCC, including 6th Avenue. It remains to be seen if TCC will be supportable as an ST3 terminus for this line of service. If a more modest extension of service were on the table, it would be important to at least reach a walkable and growing mixed use center to expand access to Downtown Tacoma and Tacoma Dome Station.

Commuter Rail

ST3 also included an extension of Sounder commuter rail service to Dupont and Tillicum from Lakewood. This portion of the plan has always been in the later years, and seems to have been contingent upon State and Federal investments in the rail corridor to build up Amtrak intercity train service. This portion of the program is not particularly expensive and there are few if any options for its replacement.

There was some discussion of expanding capacity at Sounder stations to 10-car trains, and exploration of expanded service to include nights and weekends, however, following the Covid-19 Pandemic ridership on Sounder S-Line service collapsed from a high of 389k passengers in October 2019 to 185k in July 2025. Elimination of capacity enhancements to Sounder could represent some opportunities for cost savings.

ST Express

One area that might be a possible pivot for the Pierce County subarea is development and redeployment of the ST Express bus network. Inter-city bus service within Pierce County, especially among the cities within the Sound Transit district is poor if it exists at all. Expansion of express or feeder service to areas like Orting, Dupont, South Hill, and Frederickson, connecting residents to expanded light rail at key points like Fife, Federal Way, and Tacoma Dome would spread the benefits of regional transit to more communities and would likely do so at substantially less cost than any offsets in the rail-portions of the ST3 program in Pierce County.

Closing thoughts

This is a pivotal moment for Sound Transit. The Enterprise Initiative signals that the ST‑3 vision will be reshaped. While the December 2025 opening of the Federal Way‑Seatac line is a concrete win, the looming $20‑30 billion budget gap forces every downstream project—including those in Pierce County—to be re‑examined.

Pierce County’s most vulnerable elements:

1. Tacoma Community College (TCC) extension – its long timeline, modest projected ridership in comparison with other ST3 light rail projects (TDLE, etc.), and parallel BRT designation may be factors in determining if changes are made. Although, geographic equity concerns may take greater prominence and protect this line from changes.
2. Sounder commuter‑rail enhancements – declining post‑pandemic ridership suggests capacity upgrades could be deferred or canceled for savings that could go to other projects or services.
3. Regional investments – the OMF South maintenance facility is likely to stay, as it underpins the entire network’s reliability. The Sound Transit Board seems set on retaining the second Seattle transit tunnel to connect Tacoma to Ballard, as so much environmental and conceptual design work has gone into it already.
• Opportunities amid constraints: Redirecting funds toward an expanded ST Express bus network could deliver mobility improvements to Orting, Dupont, South Hill, and Frederickson at a fraction of scaled-back investments. Strengthening bus‑rail connections at Fife, Federal Way, and Tacoma Dome would preserve regional integration while respecting the tighter fiscal reality.
• What to watch next: The next Board decisions on Motion M2025‑36, the final EIS for the Tacoma Dome Link, and public engagement will help determine which projects survive, which are trimmed, and where new service concepts should be considered. These discussions may factor updates to both the Tacoma Comprehensive Plan and Pierce County Comprehensive Plan, which both focused on the potential for transit oriented development and walkable neighborhoods.