The most expansive option would run Spokane to Seattle with a running time of 8:35 (!). As with any indirect route, it mostly has to be about travel between the intermediate cities, not the endpoints: indeed, travel within the Yakima valley comprises much of the ridership. If this route were operating twice a day in a Covid-free 2020, it would draw 205,000 annual riders – or about a quarter of what Amtrak Cascades serves in a typical year with more trains serving bigger population centers. 97% of these riders would not go east of Pasco.
This line would cost $137m in new stations and track improvements, $253m for trainsets, and a net annual operating subsidy of $23m. Shortening the line or running once a day has the impacts you might expect. However, a Pasco terminus (running time: 6:05), while not a cheaper capital project, hits a sweet spot by lowering operating costs without much loss of riders.
These are not huge numbers as capital projects go, and surveys indicate significant local interest in trying out this service. Nevertheless, the travel times are not competitive with driving. Trains have advantages over intercity buses, but such an extreme time penalty suggests Washington either expand those buses or consider a much more ambitious rail program to achieve higher operating speeds.
Last year’s transportation appropriations bill funded the $250,000 study. Today, only the Empire Builder connects Spokane with both Seattle and Portland (7.5 hours), but only once a day and not scheduled for the convenience of Seattle-Spokane passengers. Zach and Bruce Nourish wrote up the potential of this corridor 4 years ago.