Today ST released a presentation on potential alignments for the Interbay/Ballard segment (as well as others) of light rail that’s part of ST3. None of the alignments in the presentation come as a surprise, save for possibly a proposed fixed bride from the edge of Magnolia to around 17th ave in Ballard. But all of them fail to effectively mitigate the fundamental trade off with the Ballard alternatives, namely strong service to the Ballard core (and to a lesser extent decreased noise impacts) verse the substantial costs imposed by tunneling under the ship canal. Below is a proposed alternative that attempts to solve both of these problems reasonably effectively.
Going north from Interbay, the alignment (Green Line) would cross the ship canal with a relatively high movable bridge (70 feet above canal level) landing on the north side of the ship canal at 14th ave. 14th ave would have two stations, one just north of Leary and one just north of Market. Both stations would be elevated with the Leary Station likely substantially so due to the constraints of having a tall bridge over the ship canal. This is similar to the “East of BNSF/14th/Movable Bridge alternative proposed in the presentation. That option was the only option that had a cost profile in line with the representative alignment that went to voters. All other alignments were substantially more expensive.
However, this alignment would not serve central Ballard.* To do that, the proposal adds the Yellow Line running elevated between the Leary Green Line station and Market and 20th. This stub line would be about .75 miles long and require a transfer at the Leary station to get to the rest of the system. The Yellow line would operate with timed transfers to Green Line downtown service, reducing the transfer penalty to a reliable 1 or 2 minutes instead of an unreliable 0 to 6 – 10 minutes (or worse at night). Since the line doesn’t connect to the main system, the Yellow line would only need stations supporting one or two car trains, substantially reducing capital costs.
Having a stub line to serve downtown Ballard, is not a perfect substitute for direct service, but it has several advantages over alternatives.
This proposal serves more destinations
Instead of having one Ballard station this proposal has three stations, substantially increasing the light rail walkshed.
This proposal is (very likely) cheaper than subway alternatives
According to the Seattle Times, the marginal cost of tunneling to Ballard is $450 million, which it also estimates to be similar to about 2 miles of additional elevated. That $450 million figure seems low to me, but I can’t find a better number. Given that the Yellow Line plus a slightly longer Green Line add a little less than a mile of elevated or at grade track, it’s far more plausible that this alternative can fit within budget constraints.
It effectively sets up future extensions to Northgate and/or the U-district
The Green Line would be extremely well situated to continue north to Northgate and the Yellow Line would be extremely well situated to continue east to the U-district. These potential extensions are colored pink and purple respectively in the diagram above. Building these as separate lines fits a reasonable long term vision for the network.
It supports heavier upzoning in a less developed area
It’s worth remembering that this project is expected to be complete 15 to 20 years from now. East Ballard has substantial potential to grow during that time and as an industrial area near desirable walkable areas, it represents an excellent opportunity for transit oriented development much like South Lake Union did 20 years ago. Getting East Ballard up to the level of density of at least West Ballard constitutes a laudible goal. Alignment decisions should support efforts to give more people the opportunity to live in Seattle.
It provides an excuse to fix the annoying 5 way Leary/20th/Market intersection
With the Ballard station on Leary, at least part of the street would be taken by the station. Ideally, that block of Leary would be closed to cars (or function as a deadend) with cars utilizing alternatives such as 15th to Market, 20th to Market or Shilshole ave. Five way intersections are generally a anti-pattern both from the perspective of walkability and from a traffic flow perspective. Alternatively Leary Way could function as a one way street southeast bound at that intersection, allowing some traffic flow without requiring an extra light cycle.
Ballard Station would be close to street level.
The Ballard station could plausibly be built at grade. In contrast, a tunneled station could potentially be very deep. The quicker station access times in this proposal negate some of the travel time costs imposed by having an additional station and transfer.
A 70 foot movable bridge offers majestic views
This last one should speak for itself.
Ideally the Yellow Line would be automated minimizing the money spent on dwelling operators, but operational costs shouldn’t be overwhelmingly higher. Non-revenue track would also need to built between the Green Line and Yellow Line so that Yellow Line trains can access an operations and maintenance facility, adding some additional cost to the project.
Overall decoupling getting across the ship canal from serving downtown Ballard provides the opportunity to affordably build strong service coverage of Ballard and should be seriously considered by ST and relevant stakeholders.
*a movable bridge also raises reliability concerns, but I think these are overblown delaying potentially one to two trains a day for about 4 minutes. That’s not ideal, but in the context of around ~300 runs a day, it averages to a negligible increase in delays. And the system wide impacts of such delays can largely be mitigated by running the delayed train express for a few stops to make up time.