Zach’s December 5th post looking at a ST3 option to split the Link spine not only shows clever thinking on Sound Transit’s behalf, it also of course raises new routing possibilities worth exploring. This post examines the possibility this presents of an additional line from Ballard / NW Seattle to Redmond, running on Green Line tracks through the International District Station (IDS), then transferring to the Blue Line routing, shown as a potential Orange Line below:
To be sure, running a line with this configuration would add further complications to the already challenging routing interchanges south of IDS, but the advantages could easily be worth it, and far outweigh the costs of building a second Lake Washington crossing. Furthermore, such a line would help balance loads between the two downtown tunnels, increase service frequency across the lake, better connect key destinations, and prevent choke points and constricted headways through downtown.
While there are potential issues, including the technical feasibility of running twice the number of trains on the I-90 floating bridge spans, and the connections between lines south of the IDS, below are five advantages that make such a line worth careful consideration: