Sound Transit Central Link Light Rail Pulling Into SoDo Station... in FZ40 "Dynamic Art" HDR Mode

SODO Station and the SODO busway: Future home of West Seattle – southside train transfers
Photo by Joe Kunzler / flickr

When ST3 is built out, it will have two major downtown transfer hubs, at already-very-busy Westlake Station and International District / Chinatown Station. In all likelihood, transfers at these stations will not be fast, and transfer volume may be one of the factors setting minimum headway on the busiest line.

There will also be transfers going on that don’t have to happen at those two stations, and some that will certainly be happening at SODO Station. For this post, I will be focusing on the transfers that can and should happen in the SODO.

The suggestions below are probably not in alignment with the Level 1 options going forward, but there is still time to give some attention to SODO station-area details.

Cross-platform transfers at SODO Station and Stadium Station

The algorithm for how to make transfers quick in the SODO is actually pretty straightforward, and doesn’t require particularly clever engineering. It would, however, probably require tearing out some of the existing infrastructure that wasn’t built with ST3 in mind.

  • Have West Seattle to North Link tracks stay to the west. Have South Link to Ballard Link tracks stay to the east.
  • Stack center platforms at SODO Station and Stadium Station.
  • Offset the platforms from each other enough to allow tracks for each line to slide by each other vertically.
  • Have one of the SODO platforms serve cross-platform transfers between northbound West Seattle Link and southbound South Link. Have the other SODO platform serve transfers between northbound South Link and southbound West Seattle Link.
  • Have two of the tracks on the same line slide by each other vertically between SODO Station and Stadium Station.
  • Stadium Station would then be set up to have both northbound tracks serving one center platform, and southbound tracks serving the other center platform, enabling the quickest same-direction transfers between the two lines.

That covers pretty much all transfers that could be moved out of International District / Chinatown Station and Westlake Station, except for transfers that could be avoided through use of different through-routes than the current proposed basic operational plan.

Cross-line Through-routes

Having track through-routing between East Link and Ballard Link near ID/CS, and track allowing through-routing between North Link and South Link should be a high priority.

Ridership demand for these through-routes could turn out to be higher than that for East-to-North one-seat-rides and South-end-to-South-Lake-Union one-seat rides.

Regardless, having a split service pattern during peak hours, with every other East Link train going to Ballard and vice versa, and every other South Link train going to Snohomish County, would help reduce peak dwell-time congestion at Westlake Station and International District / Chinatown Station. Lowering dwell time at the bottleneck stations could enable higher frequency and higher system capacity in the future. Four extra cross-over track segments are a cheap investment compared to having to build a third tunnel.

To connect South Link to North Link smoothly and cheaply:

  • Assume the algorithm described earlier in this post has been deployed.
  • Have the West Seattle tracks pass each other vertically between SODO Station and Stadium Station. Keep the South Link tracks on their same vertical level between the stations.
  • Build two diagonal tracks from the South Link tracks just north of SODO to the West Seattle Link tracks just south of Stadium, with junctions to the main lines. These two cross-over tracks would run essentially stacked, but each staying essentially at their same height between the junctions.
  • These tracks will come in very handy for broken-down North Link trains to be able to directly access the SODO Operations & Maintenance Base along the South Link tracks.

West-Seattle-to-Ballard should have a smooth enough transfer environment at Stadium Station, rendering it better than alternating one-seat rides. Adding additional cross-over lines between Stadium and SODO would be vertically challenging. But trains from West Seattle Link will still need a reasonably-direct path to the SODO Base, to avoid tying up multiple lines due to a broken-down train. Fortunately, having the cross-over tracks between South Link and North Link would enable West Seattle trains to get to or from the maintenance base with just one turnback, at Stadium Station.

Future proofing: Duwamish Extension

If the West Seattle tracks stack up before entering SODO Station, they will need less horizontal space. Leave room at the turn into SODO Station for tracks to Georgetown and points south to junction with the West Seattle lines. Build those junctions into the track to avoid line closures if and when such a line gets built. These junctions in and of themselves ought not be expensive, but are getting tossed aside during the Level 1 alternatives narrowing process under the assumption that they are what is driving an expensive stacking of SODO Station. In reality, many operational considerations ought to lead to that stacking.

38 Replies to “Minimizing Downtown Transfer Pain in ST3”

  1. I don’t think that ST leaders realize that having level cross-platform transfers is needed. By 2035, riders will have 15 to 20 years to use Link through Seattle without a transfer so that making riders suddenly transfer will be widely understood as notably worse train service — especially if changing levels is involved.

    I think that the failure to do this will result in such a populist outcry that ST will be pushed to having blended service split to go to both lines — two lines from North Link to both West Seattle and South Link, and two lines from Ballard Link to both West Seattle and South Link. Riders will gladly wait another 6 to 10 minutes rather than endure the hassle of changing levels (which will take 2 to 6 minutes anyway, especially if riders must use an elevator or two — a high number if down escalators are omitted). With a blended system, the transfer issue becomes much less important.

    I think it’s important for all residents of Seattle to weigh in on the transfers because it affects everyone in Seattle — including those in North and SE Seattle who today or by 2021 will have a through line from one city limit almost to the other one. Neighborhood groups are increasingly going to pressure ST leaders on this and we are just being the oracles here. Thanks for putting the focus on this upcoming issue!

  2. If both lines can arrive simultaneously at cross-platforms, the transfer penalty decreases even more. At six minute frequencies, it isn’t that important. At midnight or on Sundays with less frequent trains, it can become very important.

    1. That seems highly unlikely. A train from Tacoma to SoDo will encounter about 20 stations. A few extra seconds at each station would mean a delay of a minute or two at SoDo. You could hold the West Seattle line at SoDo until the other train arrives, but I doubt that would be popular. Not only would that delay the folks that are headed downtown, but that might missing the connection to Bellevue.

      It is just as bad the other direction. You have a lot of stops coming from Everett. As you suggest, it might work very late at night, but my guess they would have to stop the train at least once a night. That might not be the end of the world, but still a bit irritating if you are just trying to get from downtown to the south end.

      I think trying to time things that well only makes sense when you are dealing with short, isolated lines. For example, the Ballard to UW line could do that (assuming they didn’t interline). A train could basically be parked there, waiting for a northbound (mainline) train to go buy. Soon after, the train would head for Ballard. It would be tricky to time things the other way, but you are really only messing with the timing on the Ballard to UW line. You just adjust it so that the waiting is minimal, but you rarely miss the other train. It also seems likely that both lines would have fairly good headways through that section into the night.

      I’m afraid that won’t be the situation in SoDo. If anything, I think it would make the most sense to try and time if so that the trains meet to cut the wait time in half. In other words, if the first train comes into SoDo at 8:00, then the other train should be scheduled for 8:03 (assuming trains are running every six minutes).

      Complicating things further is the nature of our system. There are segments in the middle of town that I could see having good headways throughout the night. Northgate to SoDo, for example, seems like it would be every six minutes at worse. But as you get into Lynnwood or Everett, you are likely to have very little demand. This means that either you just pay to run empty trains, or turn back some of them. ST is prepared to do the latter (I remember the operations chief mentioning that). So that could mean that a train could run every six minutes to Northgate, but only half of them keep going to Lynnwood. Timing that train with a similar train to the south (that turned back at Rainier Valley or SeaTac) would be a challenge. I think it is likely we will simply live with the fact that long distance trips (e. g. Federal Way to Lynnwood) will require a substantial transfer wait on average. But at least trips that are closer (e.g. Rainier Valley to UW) wouldn’t involve much waiting.

  3. The Urbanist’s idea for a 4th Ave station/Union Station reactivation also solves the transfer problem, by having West Seattle Link terminate at Union Station from 2030-2035 before switching to the current DSTT. I’d love to see an analysis of that here on STB, especially since the idea made it through to Level 2 analysis at the behest of electeds. It’s a much more elegant solution, IMO.

    1. It appears to make transferring riders still walk a block as well as change levels using stairs, elevators or escalators. That’s not an improvement to the current baseline transfer situations proposed at Westlake or ID . It’s a good idea to consider this, but it doesn’t compare with the convenience of merely walking across a level platform 20 feet.

    2. It’s a much more expensive option than what Brent proposes here. It would involve tunneling in soft soil, while Brent is proposing an aerial structure.

      If we can’t spend $100m to $150m for a fully aerial transfer station, why should we use $500m to $690m of transit money to repurpose a train station that would result in no improvement in transfer time or convenience? It’s a noble objective, but the tens of thousands of affected Link riders should really come first.

      1. The main benefit of the Urbanist idea is the transfer to Amtrak and Sounder. That is a transfer that is terrible right now. About 7,000 people a day get off the Sounder train there, so making that transfer easier would be a big bonus.

        The two ideas aren’t mutually exclusive. You could do the work to make the SoDo transfer painless *and* improve the transfer from Link to Sounder/Amtrak.

        But I would say the SoDo transfer is more important, for several reason. First, as you mentioned, it would likely be a lot cheaper to implement. Second, it would likely involve a lot more people. About 7,000 people a day get off the Sounder Train downtown. About 13,000 ride Link through there. Both are likely to increase, but I think the increase in Link will be bigger (as it expands and as Rainier Valley grows in population). Finally, assuming that Link does pair Ballard with SeaTac, making the transfer painless will go a long way towards improving trips that I’m a lot of people will make before the new line is added (e. g. Rainier Valley to UW). It is tough enough for those people to be told to step aside for West Seattle riders, but if the transfer is really bad, then it would upset a lot of people who have no idea that is what is planned.

  4. Is it that they would have to shut down the existing link line for a period of time while a conversion to a center platform takes place?

    Inconvenience to current link riders is the only justification that I can think of for not doing this, but it seems to me that the long term benefit would outweigh any short term pain….

  5. This would throw a wrench in a lot of people’s thoughts, but at SoDo:

    + Run the West Seattle line as a “left hand running” line.

    + Southbound track at SoDo winds up where the SoDo trail is now.

    + Northbound track at SoDo winds up where the busway now is.

    Sometimes this happens. E.g. Berlin s-bahn 7 operates as a left hand running line for several stations to allow better transfers.

    The busway winds up having to be one lane with directional signals for a few hundred feet. This shouldn’t be an issue.

    1. Is there any traffic on the RR tracks on the other side of the bussway?
      Google shows them removed to the north, and possiably paved over a bit to the south.
      If they are not used, Push the bussway over to where the RR tracks are, and then there is another 2 lanes worth of space to work with, without either impacting the existing line, or the bussway

    2. I could see that a three-track configuration with two center platforms at each station could work.

      A scenario: At SODO, both northbound lines from West Seattle and SE Seattle/Seatac/Tacoma would arrive using the same center track, and each side would have southbound trains in the two directions. The doors would open on both sides of the northbound train onto each of two center platforms, so that transferring riders could choose to exit the door best for exiting or transferring. Persons transferring to go in the same direction northbound could then get off an wait for the train headed northbound on the opposite line. Persons transferring southbound would be adivsed to transfer at Stadium Station, which would have swapped track configuration directions — the center track being for all southbound trains, and the two directions — UW and Ballard — being on either side track headed northbound, again with door openings in both directions but this time for southbound trains onto each of two center platforms.

      The advantage: Only three tracks at one level (two center platforms) needed at both SODO and Stadium, rather than four, perhaps stacked on two levels. It’s much cheaper and uses less space. It would dovetail nicely with the “Lander overcrossing” option.

      The disadvantage: Same direction travel would require waiting a few minutes. Some train delay could also happen if trains from the two lines are approaching the same station platform.

      The final advantage to this would be that the third platform could be put to use in emergenies, or used differently during the long construction period to minimize Link closures that are going to be required.

      1. Al, this is a good idea, but if one direction of the service can use a single track, why can’t both directions use a single track? Right now the tracks go from street level at the south curb of Lander to sixteen or seventeen feet of clearance in that block, so it shouldn’t be impossible to achieve a separation level in the same distance. If you put the platform a bit higher than it “ordinarily” would be at Lander (i.e. maybe 23 feet above street level, and have the southbound side rise up and the northbound side dip down at the diversion, you’ve set West Seattle up for the Duwamish diversion Brent — and I in the past — have advocated.

        Trying to make cross-platform in-direction transfers magically brief by having the trains pull up at the same moment is a scheduling nightmare and will fail relatively often. If all a person has to do is step off the first train and take a couple of steps into the platform, turn around and wait three or four minutes for the following train, this will be considered by nearly everyone as wonderfully easy and efficient.

        One think that Brent is supposing in his excellent article is that Stadium will be served by both South Link and West Seattle Link. That is not what the example alignment map shows. Now ST may not be wedded to having the Green Line move aside as far south as Stadium, but I can’t imagine that they made the tunnel longer than they believe necessary. So there may not be room between Stadium and the planned tunnel portal to have the necessary diverting junction at the north end.

        If that is true there is nothing stopping ST from placing it a little north of SoDo, between Lander and Holgate, and descending to the existing South Link trackage to access the new tunnel portal as shown.

        Some folks may be concerned that three lines would be using just two tracks after the mooted Duwamish line or a direct Burien line was built to use the planned diversion just south of Spokane Street. If that happy outcome did become an issue, it would not be difficult to reconnect the Green Line to the existing tracks, leaving the new elevated trackage for West Seattle and the South line. It would be good to design the junction of South Link to the new elevated ROW at E-3 and Massachusetts with that in mind.

      2. Apologies, “why can’t each direction use a single track”. I expect most people would realize that’s what I meant, but it is ambiguous.

  6. Regardless, having a split service pattern during peak hours, with every other East Link train going to Ballard and vice versa, and every other South Link train going to Snohomish County,…

    I agree that having a split service plan would be ideal. But my understanding is that the reason they are pairing up South Link with Ballard is that they don’t want to have a train running from Everett to Tacoma. An Everett to Tacoma train would be operating for a very long time, so they are trying to avoid that.

    If that really isn’t a problem (as you imply) then the second best thing (after a split service pattern) is to pair up South Link with North Link. South Link will have more riders than West Seattle Link, and North Link will have more riders than Ballard Link. If we are going to just run these lines next to each other, it makes sense to pair up the more popular lines. If that isn’t possible (because the trains would run too long) than I don’t see how we can have the split service as you propose.

    1. I don’t really think there is a need for a full Everett to Tacoma train.

      Already, ST shows that Eastlink will only run to Mariner Way. They could run Eastlink all the way to Everett, and only run West Seattle to Mariner Way. Mariner Way is also rather arbitrary, and I could see how the operation could turn back before that (Lynnwood? Northgate?) to even make the route shorter.

      On the other end, I just don’t see how four-car trains every six minutes all the way to Tacoma can make any sense from an operations standpoint. Some turn-back will likely be needed somewhere. I’m not sure how tail tracks are planned south of Angle Lake, but paying to run lots of mostly empty trains south of Federal Way every six minutes (probably 20 more minutes of driver and equipment time each way) just feels very unproductive.

      In a blended scenario, half of the Ballard trains could go all the way to Tacoma while new “Central service” line trains could stop further north, giving Tacoma only 12 minute service (or 20 minute service non-peak). In a blended scenario, the other half of Ballard trains would simply go to West Seattle. In a blended scenario, the Eastside trains could the one that alway go to Everett, and alternating West Seattle/Seatac trains could stop before that (say Lynnwood or Mariner Way).

      It really does require operational flexibility though. This is why I get frustrated that ST moves ahead with one fixed operational plan, when the reality is that they will need to tweak the plan for overcrowding, driver scheduling, yard capacities and productivity as several long lines get operating. Flexibility may be the most important consideration in a multi-line system.

      1. Good point. I agree, that would make a lot of sense. Everett would always connect with West Seattle, while Lynnwood could connect to SeaTac. Similarly, Tacoma would always connect to Ballard, while SeaTac could connect to Lynnwood. I seem to remember the operations manager talking about that sort of flexibility as it applies to turning back. So that part seems quite possible.

        Even without split operations you could do something similar. This again would mean that if you can’t have split operations, then you should simply pair West Seattle with Ballard. It would mean that trains from Everett would end at SeaTac (or even Rainier Valley), while trains from Tacoma end at Lynnwood (or even Northgate). Those are still pretty long combinations, but not much longer than Lynnwood to Redmond (which will be common well before Link gets to Everett or Tacoma).

        Does anyone have the link to the proposal on this blog for split operations? It is easy to imagine trains going here and there, but I remember someone had come up with a solid proposal that made a lot of sense. There was a nice diagram to go with it as well (different colored lines for each combination). I’m afraid Bellevue complicated things quite a bit in my head, and I seem to remember someone had it all figured out.

      2. Thanks Al, that was exactly what I was looking for. I have some thoughts, but I’ll make them later. It involves math, and as my wife likes to say, I don’t do math on the weekend :)

    2. ST went through several operational plans for ST2, some with two lines, some with three lines (Lynnwood-Angle Lake full time, Northgate-Redmond full time, Northgate-Stadium daytime). The second-last plan was Lynnwood-Angle Lake full time, Lynnwood-Redmond peak only, Northgate-Redmond off-peak. It later extended all trains to Lynnwood believing that north-of-Northgate needed the capacity.

      So the operational patterns aren’t set in stone, especially for ST3. ST2 has had more years of study and estimates so it’s unlikely to change again. But ST3 is where ST2 was in 2009, so things can still change. But some operational patterns depend on switches between the southern segments (West Seattle, Tacoma, and Redmond) and both tunnels, and ST has not given any indication whether it will build those. Hopefully it will, because the public’s needs and travel patterns may change in the future, and future lines may affect this, and if one tunnel breaks down or closes for maintenance then there may be a need to shift service into the other tunnel to avoid a mobility meltdown downtown or across the city.

      1. Maybe the three-line plan was Lynnwood-Redmond full time, Northgate-Angle Lake full time, and Northgate-Stadium daytime. Something like that.

  7. Major pain-killer: Only fare-related thing in on whole system being either an ORCA card or an App whose mere possession IS proof of payment. Loaded with an all-system monthly pass.

    Plenty of “Tap” readers around, for passengers to use as favor to system. Which most certainly will, without any threats. Or even worse,dozens of abusively worded RCW’s at dog-watering level on the wall.

    Apportioning fare revenue among seven separate agencies is what ST accounting department has been paid for all these years. And can be made more efficient by integrating all seven into one. Any agency that doesn’t like it? Please enter Option “‘Bye.”


  8. And sorry for small-d Mark Dublin abbreviation. Really did like Maryland.


  9. I’m still not convinced that sending the West Seattle trains downtown through the existing tunnel, for that interim period before the Ballard line opens, is going to cause such horrible congestion we can’t tolerate it for 5 years. Even during rush hour, the number of trains per hour that would pass through the tunnel is less than the combined number of buses and trains that pass through it today.

    During the off-peak hours, when trains are running ever 10 minutes, compared to every 6 minutes, the forced transfer at SODO looks even more silly. It almost feels like the real reason ST is refusing to consider running the West Seattle trains downtown is that it would weaken the case for why a second tunnel under downtown is necessary.

    1. It would be a tough sell during peak hours, but could make sense off-peak.

      In a few years, the rush hour service plan will be very simple. Two trains will run every 3 minutes, with a split. So Northgate to I. D. will have service every 3 minutes, while Rainier Valley and Bellevue will have service every 6. When rail gets to Lynnwood, they could either run trains there every 3 minutes, or turn half of them back at Northgate. They could also do some sort of combination. During the peak of peak, trains run to Lynnwood every 3 minutes, but a little while later, they go to 6.

      Outside of peak, things are pretty easy as well. You can just delay both lines by the same amount. So instead of the trains running every 6 minutes, they run every 8. That again means that the core (roughly UW to downtown) has 4 minute service, while the extremities (Bellevue, SeaTac and optionally Lynnwood) would have 8. Or maybe it goes 5/10. It is all pretty flexible.

      If you add in a West Seattle line during rush hour, then it means 3 trains, running 3 minutes a part. That means that both Rainier Valley and East Side degrade. Instead of trains running every 6 minutes during rush hour, they have trains running every 9 minutes. West Seattle would benefit (big time) but the other two areas would lose significantly. It isn’t clear whether it would be worth it overall, and besides, it seems bad to degrade service suddenly on two important sections for a much weaker one.

      On the other hand, you could simply apply that approach outside of rush hour. Right now, service doesn’t gradually get slower (from 6 to 7 to 8 …) but jumps from 6 to 10. So folks are used to that sort of thing. So that means a jump from 6 minutes to 9 minutes for SeaTac and Bellevue. The core, meanwhile, gets service every 3 minutes. Again, I would assume at least one of the trains would turn back at Northgate (just to save a few bucks). Either way, though, it would be an effective system. During rush hour (when the train from SeaTac is running most often) West Seattle riders would have to transfer. Outside of rush hour, they would get a direct connection to downtown and the UW. That would be a big improvement for West Seattle riders, and it wouldn’t hurt anyone.

      On the other hand, I’m not sure who would benefit. Metro could truncate buses during those hours, but that gets awfully messy. You would basically have rush hour only service, along with midday truncations. I don’t think Metro would do that. Assuming they wouldn’t, I think ridership would be very low. How many people, would get off the 120 at noon, for example, if it is just a quarter mile away from the freeway. The train only runs every 9 minutes, which means the transfer penalty is significant. Unless your goal is some place on Link north of downtown (e. g. the UW) it would make more sense to just ride it out. You would probably be downtown by the time the train arrives at the Delridge stop.

      Without truncations, I don’t think very many people will ride West Seattle rail. A few from the junction, a few from Avalon, and that’s it. Similar stops (e. g. Beacon Hill, Columbia City) have less than 3,000 riders a day. So the West Seattle line would likely have well under 10,000 walk up riders. I’m not sure it is worth the hassle when so few will benefit. In comparison, the 41 carries well over 10,000 a day, yet little is being done to prevent its temporary delays. West Seattle ridership is built upon the notion that people will prefer making a transfer, or that Metro will simply force them to. During rush hour — when buses can be slowed down, and the train runs frequently — a lot of people will benefit. Outside of rush hour, very few will. Without the ability to tie the West Seattle line into the main line at rush hour, it seems like a very weak project.

      Of course ST could spend money making the trains run faster through the core, but decided not to even investigate that (and instead go ahead and build a new tunnel).

      1. Good point about peak service requiring uneven headways on the other (more popular) lines – didn’t think about that.

        I agree that if the train has a forced transfer in SODO, truncating buses would not be acceptable, but if the train goes all the way downtown, it’s exactly the same situation for West Seattle (off-peak) riders as it would be when the second downtown tunnel finally opens, and the trains move to their permanent configuration. If Metro can’t even truncate the buses during the off-peak hours, even if the train does continue through downtown, one has to ask – why are we even building the West Seattle line to begin with?

      2. “why are we even building the West Seattle line to begin with?”

        Because Dow and several powerful politicians live in West Seattle and want it.

        It’s absolutely silly to build a stub line to SODO for a few years. Metro rightly won’t truncate the buses, so ridersip will be mediocre. When the tunnel is finished, Metro will do in West Seattle the same thing it plans to do elsewhere: alter some one-seat rides to go to areas Link won’t directly serve, like First Hill. That way people still can take a bus downtown but it won’t go directly to Third Avenue (use Link for that), and if they want to take a bus to Third Avenue they’ll have to transfer in First Hill or SLU or Pioneer Square. Metro will also convert some routes to crosstown lines (the C) and truncate minor routes. All that assumes a high budget in order to maintain the one-seat rides it plans to keep (with alterations) and the universal high frequency it promises — so reality may require cutting back. But the argument for this network is that there will be enough demand to fill both Link and the bus routes, as Community Transit discovered when it overlaid Swift on top of the 101, and Metro positioned the 49 as the primary route on Capitol Hill even though some trips are diverted to Link. The population will continue to grow and and people will likely become more transit-using over time, and the network will be ready for them. But West Seattle in particular is a difficult situation, because of its geography and because they were too hasty with Link, so now we have to make the best of it.

      3. There was an alternative to the West Seattle stub: build DSTT2 and Ballard first, then come back and do West Seattle. But the politicans wanted to show early return on investment in West Seattle, and so we get the stub.

      4. The West Seattle stub opens the same year that Link to Tacoma Done opens. I’m not sure if the SODO segment can handle the crowds. The trains will be standing room only well before SODO — and a surge of West Seattle riders could easily be too much. A few trains may have to pass by before a West Seattle resident can get on one.

      5. Al,

        The only folks who will choose the bus-train-train option will be those who are riding beyond downtown Seattle. Everyone else will just stay on their local bus; I doubt Metro will truncate the 120, 21 or the X buses from West Seattle until the West Seattle trains go on north.

        There won’t be that many new riders at SoDo.

    2. I still think ST purposefully gave West Seattle early but bad route. If ST gave WS a later route, WS would complain and push to be earlier. Now that they get their route early, they will be focused on fighting about where it will go in West Seattle. By the time they figure out how it will go in WS, the tunnel will be ready and the line will open like normal

  10. One thing I don’t get is how it makes more sense to force a hundred people to transfer rather than one driver to transfer. More people will be going south-north than Ballard-south or north-west Seattle. So how is making all those extra transfers better than just having drivers swap out downtown?

    1. The drivers don’t have to swap out downtown, necessarily. ST, could just cheap out on the passenger experience and do those spinal swap-outs with annoying special stops at the O&MF base, as it does now. The base will probably be closer to the half-time point in the spine than downtown is.

      I suppose I have to find agencies that have 90-minute-plus train runs that require mid-run driver swaps to show it can be done smoothly over the course of three stops (one to board and then get to the cockpit between stops, one to trade off while stopped, and then another after the first operator has made her/his way to a door).

      Swaps can be done without slowing down the train. Lots of passengers unnecessarily transfering, not so much.

    2. The technological irony is that by 2035, virtual cabs and driverless technology will have progressed to where the jobs will be very different (monitoring rather than driving) and may be doable remotely or completely eliminated. Except for MLK and isolated, gated grade crossings, the system will be pretty exclusive from the surroundings — so train driver control could be reduced to the more exposed segments even today.

      1. Agree – 2035 is a long time away, and automation of trains in a controlled environment is much less of a technological challenge than automation of buses and cars on city streets. Hopefully, physical track will exist to at least allow the option to the West Seattle trains to Ballard and Tacoma trains to Everett. ST can decide whether to do that based on the technological progress (and union resistance) at that time.

        That said, it would be irresponsible for ST allow the fate of a multi-billion-dollar project hinge on speculative technology improvements which may or may not actually happen. Regardless of what ST ultimately ends up doing, they have to design the line today with the conservative assumption that it will be operated by humans, like the trains of today.

  11. First about the MF access, the West Seattle line is designed to have a new access to the MF along Horton Street. So we don’t need to worry about reversing between two isolated systems.

    But more to the point, why do there need to be more than two tracks, at least for the next two decades? Everything could be massively simplified by having all northbound trains on one track and all southbound trains on another. Yes, have the tracks stacked one over the other so that junctions are made without level crossings, but there will NEVER be trains to and from West Seattle more often the every six minutes in the most optimistic scenario imaginable. The Green Line is limited to once every six minutes by traffic issues, and I can’t imagine that a Duwamish Bypass or Burien Line with four car trains (capacity 600 at least) will need more than every six minute service in the foreseeable future.

    Doing this means that the most critical transfer, the in-direction change of destination, is maximized. The passenger steps off the her or his originating train, takes a few steps to clear the door, stops, turns, and waits for the next following train to her or his destination. When it arrives, she or he takes the same few steps forward and boards the train. There is no better transfer in transit.

    Grant, this would make the out-of-direction transfer less efficient than a cross-platform; a change of level is required. But in all honesty, how much out-of-direction transferring will there be between a West Seattle stub with three stations and a lot of forced bus transfers and the slow Rainier Valley line to the airport and points south. Remember, the new line does not serve Harbor Island.

    I doubt there is much potential ridership at all, especially since there is planned to be a direct RapidRide route between many West Seattle points and the airport some time in the next decade.

    What I would propose is that SoDo and Stadium be built with vertically stacked tracks to accommodate the necessary junction to the north of Stadium and the one or two south of SoDo. The platforms would be to the east of the newly built tracks but designed to be center platforms should a second pair of tracks be necessary in the future.

    To accomplish this, the southside parking on Forest east of Sixth Avenue South would have to be captured, but that’s only a couple of dozen slots. To make things work, the upper level of the new stacked structure would be northbound, and the lower level southbound. The new structure could be tied directly at the same level to the current southbound track at the beginning of the curve between the busway and Forest. Everything else about the north side of the MF would remain as is except that as the northbound track leaves the tunnel it would have a turnout added to continue straight rather than curving. That track would immediately begin to rise and by the time it has reached Sixth Avenue South should easily be at the upper level of the new structure. It would cross over the existing trackage and join the northbound West Seattle tracks just south of the SoDo station.

    I would keep the northbound South Link track as far as the tunnel portal so that trains entering service to the north can do so as they do today should capacity require it. However, there is no reason that a structure build over Horton could not allow trains to enter service both to the north and south by “wyeing” at the MF boundary with the left branch climbing to achieve the elevation of the upper deck while the right branch stops rising at the lower level of the structure.

    The is no need to replicate that wye for trains entering the MF. Those coming from the north can follow the path they do today, while those from West Seattle veer right just south of Horton.

    That should certainly be more than adequate until a Duwamish Bypass or direct Burien line is built. If at that time the existing tracks are at capacity then if this is built correctly another pair of tracks on a new structure can be added to the east of the stacked platforms.

    Now such a change would make the in-direction transfer a little bit more walking, since it would become “cross-platform”. But the proposal in the post has all in-direction transfers cross-platform from the beginning of service. This proposal at least gives in-line, same stop transfers for a couple of decades.

    1. Oh, I forgot to emphasize that the curve of the new higher structure at Forest Street should be laid out such that it attains a north-south tangent parallel to the West Seattle track and then curves over, making an “S”. This is to ensure that in the future it can continue north on the second set of tracks mentioned above.

    2. And I got confused on the Horton wye. Since the upper level is the northbound direction, the right hand branch of the why would climb to the upper level and curve right into the busway to join the upper track. The left branch would stay at the lower level (one above the street) and junction with the southbound track for trains entering service to West Seattle. Trains leaving service from West Seattle would come down from the upper level and turn right into the distribution circle around the MF.

      Trains leaving service from the RV line would take the left branch at the new turnout at the tunnel mouth and stay on the existing track to the crossovers at the MF north junction, as they do today.

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