Pundits claim West Seattle had been added to the ST3 plan by politicians envious that Ballard gets a light rail connection. It seemed easy to draw another line on the map, but now that Sound Transit published the final Environmental Impact Statement for the West Seattle Link Extension (WSLE) it has become evident that it is far more complex than anticipated. While the ST3 measure promised to bring 37,000 riders for $1.5 billion ($2.4B in 2024 dollars) by 2030, now the price tag has tripled to $7.1 billion (in 2024 dollars), and completion is delayed to 2032, and the ridership forecast for 2042 (after WSLE is connected to the current downtown tunnel) is only 27,000 new riders systemwide.
The delays and cost explosions are directly related to the apparently-unexpected complexity of building the extension as drawn in 2016. The route needs to roller-coaster up over the Duwamish and Pigeon Point, down into the Delridge Valley, and then back up to the Alaska Junction. To ensure southward expansion in the distant future, the station at Alaska Junction was rotated to be north-south, requiring more property takings. To avoid disturbing the Duwamish superfund site, the new bridge needs to stay away from the river shore. The SODO soil is prone to liquefaction in an earthquake, so the elevated guideway pilings have to be extra deeper than normal. The Pigeon Point slope is unstable and requires large retaining walls. The initial setup for tunneling is expensive, even if the tunnel is relatively short.
Sound Transit staff told the Board the more expensive Preferred Alternative would require third party funding, but now they’re assuming Seattle, King County, and Sound Transit will somehow find the funding, which is implausible given the large shortfall. If the Board decides to proceed with the current plan, they may choose the same approach as they did during the pandemic finance crunch (“realignment”): delay delivery until they collect enough cash from tax payers to avoid breaking the debt ceiling.Â
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