At the Ballard Town Hall meeting Sound Transit made it clear that they do not want to make any major changes to the BLE plans to avoid starting all over with the EIS process. They did consider at some point starting with a connection between Ballard and Westlake and delay or even skip the second downtown tunnel (DSTT2). But that would require a separate operations and maintenance facility (OMF) at Interbay or connecting to the existing downtown tunnel (DSTT1). The tunnel is old and surrounding soil is unstable and therefore they concluded this would be very risky and costly. Tom Terrific however suggested a single-track maintenance tunnel connection which would connect at the end of the current tunnel by the Convention Center.
While any major design change (such as an elevated line) may jeopardize the current EIS process, implementing a project in phases is common and accepted. Not spending $8b on a second downtown tunnel at this point would allow Sound Transit to connect Ballard much earlier (in particular if paired with other measures such as automating the line or a ship canal gondola). With all the downtown complexities it would also reduce a lot of risks. And as half of the tunnel is paid by funds collected in Pierce and Snohomish County, it may even allow Sound Transit to finish the spine earlier, a goal the Board keeps reiterating.
Sound Transit has also stated that the Ballard line is necessary to connect to the Tacoma line as an Everett to Tacoma line would get too long for operators, but they could turn Tacoma trains around at Northgate or just change operators halfway.
Sound Transit studied alternatives for a second tunnel. Either the line could connect to the existing tunnel (interlining) by tapping into the existing tunnel at Pine St and 3rd or operate as a separate line with a separate OMF at Interbay. They determined that both options would not be any cheaper than proceeding with a second tunnel. I tend to agree with the risks involved with tapping the existing tunnel for interlining. However, Tom’s suggestion for a single track to connect a Ballard line with the existing tunnel should warrant further research. To reduce operational impact, such track could be used during off-hours. It would allow maintaining trains at the SODO OMF instead of having to build a separate OMF.
Before the original tunnel was extended to Capitol Hill with a slight curve to the south, it used to have a track extending straight east of the Westlake station for trains to turn around. It might be possible to extend that tunnel portion and add a north turn. You may need to use the I-5 Express Lane exit to build such track. That track could then connect with the Ballard line roughly at the Denny station. It would be fairly long but for a maintenance track that should not matter as much.
Adding such a maintenance tunnel would be expensive, but not nearly as much as building a second tunnel or a separate Interbay OMF. I hope it would allow Sound Transit to serve Ballard well before 2042.