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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:

ST3 Orange Line

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:

Prime candidate for frequent headways. Eastside / Downtown Seattle is among the most important transit corridors in our region, with bi-directional peak commutes, important cultural facilities and events boosting non-peak travel, and severely constricted choke points. Short of Northgate to Downtown, the Eastside is perhaps the second most important travel corridor in the state, and should be given serious consideration for our most frequent Link headways. While this demand could be addressed with a second Lake Washington crossing, potentially increasing options for travelers, doing so would mean splitting service frequency over two routes for all stations where any such lines don’t overlap. Running an Orange Line as outlined above would make travel twice as frequent for the entirety of East Link and Ballard / NW Seattle, including SLU.

Would make greater use of planned infrastructure. Running an extra line from Ballard to the Eastside via a new DSTT and the already planned East Link tracks would dramatically increase service without the added expense of a new Lake Washington crossing, new tracks on the Eastside, or yet another DSTT. The new DSTT would be better utilized by having twice the frequency and increasing the area covered without forcing a transfer at IDS or Westlake.

While the cross-lake corridor could be served by adding a route that diverts south or southwest once arriving in Seattle, instead of to Ballard, this would require the majority of riders to transfer to continue on to Downtown / SLU. SLU / Ballard is the most logical and needed routing for an additional line running on the East Link corridor.

Requires the least amount of new infrastructure. While there are many ways to meet future cross-lake travel demands, the only way to do so without requiring massive new infrastructure investments is to run a second line along East Link routing.

Adds capacity without constricting headways. Improving headways on East Link without running a new line through the proposed new DSTT would run into challenges with increased competition for capacity in the existing DSTT, meaning reduced headways for the lines already planned for this corridor. By routing increased East Link frequency through the second DSTT, currently planned headways would be preserved, resulting in no increased choke points or reduced service to points north or to West Seattle.

Connects key tech hubs. As the two primary tech hubs in the state, SLU and the Eastside are becoming increasingly linked, as seen by Expedia’s decision to move to Interbay. As our transportation infrastructure grows, and workers migrate between companies but don’t necessarily relocate their families, it isn’t unreasonable to expect Ballard – SLU – Bellevue – Redmond to become one of our major commuting corridors. Without such a line, these commuters will end up placing heavier loads on the planned lines (Red and Blue) running through the existing DSTT, and make transfers at Westlake and the IDS much more common than they need be. Routing a new Orange Line such as this would help balance these loads across the two downtown tunnels, and make for more seamless travel at some of our most critical and busiest stations.

14 Replies to “Splitting the Spine: Ballard to Redmond option”

  1. I like the idea of 2 lines across I 90 with one going to Ballard and the other to Northgate.

    However, I would recommend a different service pattern on the east side. Have the orange line go Ballard -> Totem lake. This gives a one-seat ride between Kirkland/Totem lake and Seattle.

    Then, truncate the Purple line in Bellevue, where you’d get a transfer to the frequent orange + blue pair.

    This pattern would reduce the frequency from Redmond -> Bellevue, but I think that’s okay as Bellevue may generate more ridership than Redmond alone (I suspect much Redmond ridership would use 520 BRT).

      1. I think they’re both (Totem Lake and Issaquah) great options. Truncating the Purple Line makes sense, though it would also make it a pretty short route – not sure if this is a negative aspect or not, but I guess that depends on the demand for people traveling between Kirkland and Issaquah, which I wouldn’t guess to be too high but I honestly have no idea. The other issue is whether or not there’s a need for higher frequency on any of the spokes coming out from Bellevue, and which of these involve lots of through-travel to Seattle.

    1. I would agree with Stephen. Demand on East Link will fall considerably east of Downtown Bellevue, as it does on Route 550 today. Going to Totem Lake would be awesome.

      As for the Issaquah leg, I’d suggest merely terminating it at South Bellevue if the Mercer Slough crossing would be allowed. The line could even have single-track portions between stations to save initial capital costs.

      1. I think we’d need to understand where exactly the masses getting off the 550 @ BTC go. If a significant portion are getting on local buses to head further east Link ridership may not decline that far and local eastside route revisions might warranted once it opens. I’ve never seen any #’s on that though and frankly I don’t even know if the bus changes required to support East Link have really been discussed yet.

        Odd corner case example: I know from doing it myself that a surprising # get on the 532/535 and go up 405 since when traffic is bad on I5/520 it can be faster than the 25x/311 to Totem Lake.

      2. I get on RapidRide B. With Link I’ll probably stay on a couple more statijons, although the walk at the end would be longer unless there’s are new north-south bus routes. Wilburton may also become a popular transfer point between Link and the B if the stations areq closer together than at Bellevue TC, and perhaps some 234/235 riders will also use it.

        My impression is that most people waiting for the westbound 550 walk to it, but I don’t really know.

    2. The main problem I see with this is that it puts Overlake service in two tunnels with different stations downtown. That means that people won’t be able to “take whichever one comes first”.

    3. I agree with this, but just delete the purple line altogether. That line is dumb and unneccessary, Issaquah should just have ST express to mercer island.

  2. North of the Ship Channel, this would provide an opportunity have one line run east towards Fremont and maybe UW, while the other could continue further north.

  3. Please stop showing Issaquah to Kirkland with only a connection at Wilburton. This is a very conceptual line and you are furthering conceding defeat on the f***ing Slough so early on.

    1. I’m all in favor of running the Issaquah line through the Slough, and think Wilburton is a pretty awful routing. In making the map I was trying to simply show a representations of what another line could look like piggybacking on the Green and Blue lines, and used Zach’s post as a base to work off, since this is what it was building on in the first place. In order to not confuse the issue with extraneous (though very important) additional points, it seemed best to simply leave that portion the same. The real issue I was getting at is that it wold be a waste to not plan a second line across I-90 (if feasible), and for a relatively very small investment we could gain a lot. How this might actually look is open to discussion, so let’s get some more thoughts out there! Al’s comments are great examples of how to take this a step further.

  4. A few thoughts: First of all: Nice map. I like all the pretty colors. Putting aside the pairing for a second, it does show how ridiculous the light rail plans are. Overlay a census map (showing population density) and it looks ridiculous. Add an employment density map and it still looks ridiculous. Throw in a plausible bus network, and it is even worse. This is not a criticism of the pairing or frequency you suggest, but simply a weakness with the overall plans.

    The most important corridor is the UW to downtown. But the corridor to the East Side may be second. Of the possible routes they are considering, it is highly that it is second. So there is that.

    In areas where the lines double up, it is best if demand is roughly twice as high along that section. For example, a Ballard Spur along with a Lynnwood Spur could combine at the UW. This would enable high frequency transit (e. g. every four minutes) along the key corridor (UW to downtown) while enabling lower headways (e. g. every 8 minutes) to the north and west.

    With that in mind, your idea is reasonable (assuming the ridiculous set of light rail plans is built) but only if you have a bunch of turnback stations. Demand from Lynnwood to the UW will be much smaller than demand from the UW to the south end of downtown. Demand from downtown Bellevue to downtown Seattle will be much higher than Redmond to Bellevue. So, with similar turnback stations it makes a lot of sense.

    Of course, if you avoid building a light rail line to West Seattle (which many people consider silly) than you don’t need to worry about the doubling up. Run the Ballard line to Bellevue, and keep the current north-south alignment. Add turnback stations and you are done.

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