Learn from Toronto: Automate Ballard Line

When Toronto faced escalating cost on their relief line, instead of extending their existing subway network, they decided to build a separate Ontario line and use lighter and shorter automated trains rather than their prior subway trains. Lighter trains mean faster acceleration, allowing steeper climbs including from within a tunnel to shallow stations and even elevated portions and smaller tunnel diameters. Shorter trains mean smaller stations which can fit more easily into the existing urban landscape. A separate line minimized the impact on the rest of the transit system.

Ontario Line rendering by Transdev/Metrolinx

As Sound Transit ponders escalating construction cost, it may want to consider the same. It may not only save them money during construction and operation, it may also provide a better ridership experience.

As subway ridership in the downtown core grew, a new relief line" was discussed to ease congestion at the intersections of Line 1 (yellow) and 2 (green). Soon its cost estimates escalated. They finally hired Michael Schabas as a consultant. He had worked on automated lines in Vancouver, Honolulu and London. Within 3 months he came up with a plan for the Ontario line. By building a separate line with the latest light metro train and signal technology, it would not need to integrate with their older network and could be procured more independently. As lighter trains allow for steeper climbs and tighter turns, they provide more flexibility in using tunnel, at-grade, and elevated sections. That included using a bridge over the Don River rather than a deep tunnel underneath.

With new leadership in place in Seattle, a similar approach could be used in Seattle to accelerate the planning efforts and use the technical advantages of automated light metro trains to build a better line for Ballard:

1. Shorter stations mean better stations. They can be closer to the surface or in better locations (e. g. squeezing in between building foundations). The Denny station may fit on the SLU Discovery Center park block. This would reduce construction impact.
   Stations and their approaches need to be straight and level as the driver needs clear sight lines. Shorter automated trains are far more flexible: trains can turn or go up or down right out of the station. That may allow for pushing both the SLU and Seattle Center stations further east.
2. Automated trains allow for higher frequency and longer operating hours. Vancouver has trains running every 90 seconds. Copenhagen runs their trains 24 hours on weekends.
3. Modern light metro trains also allow for smaller tunnel diameters which reduces construction costs.
4. Better for current riders. With a new tunnel, riders from the south (e. g. Rainier Valley) are much worse off. They lose their good downtown stations. They lose their direct connection to the UW and other north end destinations. Their transfer for trips to the East Side will likely be much worse. Riders from the north (Capitol Hill, the UW, Northgate) will lose their one seat ride to places like Rainier Valley and the airport. This can all be avoided by building a second, independent, automated line.

With the recent ST3 cost increases and Sound Transit rethinking their plans to serve the region, several board members have suggested that a second downtown tunnel (DSTT2) may not be affordable. On their behalf Sound Transit has been evaluating alternatives such as interlining or a separate stub line (the Stub-End alternative). The blog had four articles on this; see the archive December 15-21, plus the open thread December 17 starting here.) The Stub-End alternative is similar to an alternative I outline last year and that many on this blog contributed to.

While the Spine has a lot of political momentum, a separate Ballard/SLU line would provide the highest ridership opportunity for our regional network and an opportunity for our region to catch up with the latest urban transit technology our neighbors in Canada, Hawaii, and around the world have been using for many years.