ST3 Truncations

Truncation Options under the 3 approaches

Sound Transit finally addressed their severe budget shortfalls at the March 18 Board Retreat. The transit agency looked at three different approaches to build ST3. All three approaches investigated involve heavy truncations with some lines being completely eliminated.

Overview of Approaches

Project	Approach 1	Approach 2	Approach 3
Ballard	Truncate to Seattle Center w/o SLU	Truncate to Smith Cove w/o SLU	Truncate to Seattle Center w/o SLU
West Seattle	Construct to Alaskan Junction w/o Avalon	Cancel	Truncate to Delridge
Everett	Construct to Everett	Construct to Everett	Truncate to SW Everett Industrial Center
Tacoma Dome	Construct to Tacoma Dome	Construct to Tacoma Dome	Truncate to Fife
Graham+Boeing Access infill	Cancel	Cancel	Construct fully
T Line	Cancel	Cancel	Truncate partially
Kirkland/Issaquah	Cancel	Construct fully	Truncate partially
Sounder (DuPont)	Cancel	Cancel	Construct fully

Above is a summary of the 3 approaches. We'll discuss them in more detail below. A more detailed log of the meeting might be a in a future article.

Approach 1 Build West Seattle, Cancel IssaquahApproach 1

The first approach would build West Seattle Link to the greatest extent while canceling the Tacoma Community College T Line and South Kirkland-Issaquah Line. Ballard Link would be truncated to Seattle Center without SLU station. The Sounder South DuPont Extension would also be cancelled.

Dow Constantine while staying mostly neutral was a proponent of this approach arguing that the line is shovel-ready". The other board members were hesitant to commit so much money and sacrifice their extensions though.

Approach 2: Build Issaquah, Cancel West SeattleApproach 2

The second approach would build South Kirkland-Issaquah Line while canceling West Seattle Link Extension and also cancelling the Tacoma Community College T Line. Ballard Link would built slightly longer to Smith Cove but still truncated. DuPont Extension is still cancelled in this approach.

Dan Strauss, the city council member for Ballard, liked this approach but still implored Sound Transit to find a way to reach Ballard itself.

Approach 3: Build half of everythingApproach 3

This approach would build half of everything.

West Seattle Link Extension would be truncated to Delridge. Ballard Link Extension would be truncated Seattle Center. Tacoma Dome Link Extension would newly be truncated to Fife. Everett Extension would be truncated to SW Everett Industrial Center. The infill stations would be built.

T Line Extension and the South Kirkland-Isssaquah Extension would be built to some unknown initial phase. Also the Sounder South DuPont Extension would be built under this approach.

Approach 4: Unknown

Technically the cost savings can be mixed and matched. However there are only so many ways to save tens of billions of dollars. The largest cost overrun has always been Ballard Link Extension. Any major cost saving measure would at a minimum need to truncate the line to Smith Cove.

Defer"

While Sound Transit officially categorized many projects above as a deferral," the lack of a defined timeline or secured funding confirms a much more permanent status. For most residents, a multi-decade delay (20 to 30+ years) is effectively a cancellation.

Individual Savings

Sound Transit has yet to provide a granular breakdown of the savings tied to these truncations. While a station breakdown would be ideal, it has been a full decade since the 2016 vote and the agency still refuses to release more in-depth financial numbers. Rather than waiting indefinitely, the following breakdown is a guess of the financial savings/cost.

Ballard Link ExtensionBallard Link Extension annotated with cancelled segments

Currently Ballard Link Extension costs $20.1B - $22.6B dollars.

Smith Cove truncation could probably save around $1.9B - $2.6B dollars skipping a new Ballard bridge and Interbay station. Seattle Center truncation would eliminate the Smith Cove station as well. Probably in total save $3.0 Billion - $3.8 Billion.

Removed SLU station with shifted west Denny station

Removing the SLU station will save around $1.5 to $1.7 billion

In any scenario the vast majority of the money would be spent building the new tunnel from Stadium to Denny costing around ~$12 to $14 billion.

West SeattleAlaska Junction savings

Building the original alignment as designed in 2025 would cost $7 billion.

Dropping Avalon will save around $400 million dollars and adding the reconfigured Alaska Junction with shifted crossovers will save ~$2 billion to around $4.9B-5.1B dollars.

Truncating at Delridge will add some further savings potentially saving up to $4 billion dollars. Though this would still mean Sound Transit is building a single new station for $3~4 billion dollars.

Infill StationsInfill stations

Boeing Access Road station cost ~$425 to $475 million. Graham station will cost ~$175-$200 million.

T Line ExtensionTacoma Community College Extension

Tacoma Community College extension will cost around $1.4 - $1.6 billion 2025 dollars (estimated to be $2.5 billion in YOE) from the Enterprise Initiative: Scenario development & capital delivery.

DuPont Extension

The Sounder South dupont extension was estimated to cost ~$450 million dollars in 2023.

Everett ExtensionEverett Extension phased delivery

The full Everett Link extension will cost $6.8B - $7.7B dollars. The truncation at SW Everett Industrial Center aka Boeing will probably save around $1.8B - $2.5B. (The jog to Boeing is elevated and costs more than the I-5 at grade freeway segments).

Tacoma Dome ExtensionTacoma Dome Link Extension annotated

The Tacoma Dome Link extension costs $5.4B - $6.1B dollars. Truncating the line to Fife will probably save around $1~2B dollars. A large portion of savings comes from skipping a Puyallup River bridge.

South Kirkland and Issaquah ExtensionSouth Kirkland and Issaquah Extension annotated

The South Kirkland and Issaquah Extension will cost $5.6 billion to $6.3 billion. If cancelled will probably save that entire amount.

Accept Truncations vs Build Cheaper?

The only other way to build all the extensions would be to redesign cheaper alignments. Historically, Sound Transit has prioritized choosing the politically easy path over increasing the budget. For example, elevated stations built over businesses rather than the road for Everett Link, added tunnel segments in both Ballard and West Seattle, and very deep tunnels and deep stations for the second transit tunnel. While other agencies pivoted during the post-COVID inflation spike, Sound Transit doubled down, choosing a billion dollar tunnel for Alaskan Junction over a cheaper elevated route. Making matters worse, the Board effectively banned at-grade alignments and also refuses to build elevated alignments where possible.

It remains unclear if the transit agency would be willing to redesign or more importantly if the residents are willing to accept larger community impacts to avoid truncations. Past struggles do not showcase well: 1) For Lynnwood Link and Federal Way, the agency was unable to build along elevated SR 99 and the agency retreated to build along the I-5. 2) In Kirkland, the segment was truncated to South Kirkland because the residents would not allow a light rail along the Eastside Rail Corridor. Before Sound Transit can attempt pivoting to cheaper alternatives, the metro area would need to be much more accepting of community impacts whether property takings, environmental impacts, car traffic increases, etc...

Conclusion

The Seattle metro area will have a harsh choice deciding what to build. Either Issaquah, Tacoma, or West Seattle will likely draw the short straw. While transit agencies in other countries could choose cheaper construction methods and alignments, the Seattle region is likely unwilling to accept the amount of construction and environmental impacts that low-cost metro building requires.