Oran Viriyincy/Flickr

As someone who’s a big fan of center platforms in general, I asked Sound Transit spokesman Bruce Gray what the prospects were for East Link to add a center platform where it meets the Central line:

A center platform at IDS was not studied as part of the EIS plans and isn’t in the works for final design. As I understand it, there was discussion of this early on but the following issues are the main ones that precluded moving forward with it:

  • Difficulties having enough space to add elevators/escalators for a center platform given the space constraints in IDS
  • Fire/life/safety codes make it difficult to fit a wide enough center platform that could accommodate the crush loads we see at rush hours, much less game days
  • Potential need for a turnback (pocket) track at IDS
  • Our long-term ridership projections put Eastside > Airport travel at about 3% of daily ridership – not enough to warrant the costs/risks associated with what it may take to do a center platform

This may be one of those things where I can’t be moved by any arguments weaker than “this absolutely cannot be done,” which is not what I’m hearing. This is a minor project in the scheme of things, but it’s another example of the system punishing transfers as much as possible. If you have luggage, a stroller, or a wheelchair, it’s no small thing to take two elevators instead of simply walking across the platform. Even if you’re an able-bodied youth, it’s frustrating to see the train on the other track as you pull in, knowing you’re never going to make it.

It may be primarily inattention to detail by Sound Transit, or astonishing lack of foresight by the designers of the DSTT. In either case, it’s one more item where decades from now, riders will wonder “what were they thinking?”

127 Replies to “No Center Platform at Chinatown/International District”

  1. OTOH, ST could offer a training course in how to safely dash across both tracks to get from one platform to the other. Certification could be ‘capped’ off by issuing special color hats, so that security knew these mad-haber-dashers were professionals.
    Hell, I’d sign up for that!

    1. Actually, that’s not a crazy as it sounds. Why not have a designated and signaled crosswalk monitored by the station safety personnel to cross the trackway?

      1. I don’t even see why you’d need safety personnel. This has to be safer than the at grade sections, with trains and cars to watch for and longer crossing distances.

      2. So, let’s make frequent suggestions to Sound Transit to implement this nearly free solution to this problem.

      3. There is a precedent for a crosswalk at Convention Place station. The buses that terminate there have taken to letting people off at a side platform, and you have to walk across a bus lane to get to the exit.

  2. Assuming the Seattle Subway gets fully funded, transfers will likely happen at Pioneer Square once the express line through Georgetown is built. Not the end of the world, IMO.

    1. Transferring at Pioneer Square adds extra length and four minutes to the rush to catch a plane. I don’t see airport-bound riders having the patience to ride the extra station even if they know the center platform will be there. More to the point, I don’t think most riders will think about the center platform one station beyond.

      1. So one would leave home 5 minutes earlier – what’s 5 minutes on a trip to NYC? .1% of travel time – no biggie, huh?

      2. I bet the Pioneer Square center platform doesn’t happen, either. Not enough riders to justify it (and even less since many riders would still transfer at IDS). Need for elevators and stairs. Pocket track or passing track?

      3. It’s a larger percentage if you’re going to the airport to meet somebody or going to work. Every five minutes means some number of people will choose to take a shuttle or drive rather than taking transit.

    2. One of the crazy ideas we’ve had for Seattle Subway’s new tunnel would be a stacked tunnel under 4th Ave, between ID station and King Street. You’d still have to transfer, but boy would it be a good opportunity to connect all our rail services together.

    3. The question of where would the transfer stations be is still open. If the tunnel is on 2nd, University Street would probably be the cheapest place for a transfer station because it already has an entrance on 2nd. But for passenger convenience the best places are Intl Dist or Westlake. One option would be to make all the DSTT stations transfer stations (except Convention Place of course), but that would be expensive and perhaps budget-busting.

  3. I’m going to agree that ‘difficult to get right’ shouldn’t be an excuse for discarding the best solution for passengers. Tunnels with long sloping ramps that go under the tracks are a easy solution to the center platform issue and you end up with only a small opening near the center or at the ends of the center platform.

    However, even lack of foresight in a design can be worked around with a bit of engineering. Take the deployable ramps to the monorail at Westlake for example. Simple solution that could be made use of for getting over one set of tracks or another.

  4. The roadway in the tunnel stations are 4 bus lanes wide. Link only needs two leaving 2lane wide area for a platform … that would be wider than the existing side platforms. If they really need an extra track to store a train … build a yard/storage tracks at CPS which will be closed anyway.

  5. Even worse is Convention Place tunnel station – it has Bays A to D, but switching between bays is often hard – this leads to people waiting on top of the stairs for the next bus to go in the tunnel and then running down the stairs to catch it. Prone to accidents.

    It would really help a lot if the blog can shine a light on this, and ask them to add bay-crossings in convention station.

  6. The 3% of ridership projection is a self-fulfilling prophesy. We don’t expect eastside riders to switch to Link from the 560 (or, to a much larger extent, driving) due to the time it takes on Link. So, why invest in building a transfer platform that might increase that projection to 5 or 6%?

    It reminds me of the folks who ask why build bike lanes on NE 125th St (as one of many examples), when people aren’t biking on that unsafe street?

    Also, there are people who will be living along MLK trying to get to jobs on the eastside (or vice versa even — Call King County Now! Save four minutes on my commute to ACRS!). There are many station pairings between South Link and East Link that have to be considered, not just eastsiders going to the airport. So, there is justification in spending some north subarea money on this project. (The supposition that it would serve east and south subarea riders exclusively may be an argmument he forgot to mention.)

    So, if 200th St. Station only adds 3% to Link ridership, why are we building it?
    .

    Safe width: Those platforms at ID Station are currently too narrow getting around the elevator. Bogus argument.
    .

    Pocket track: Any guesses as to what they would do with pocket track, or for that matter, why it would be in the middle of a station, especially IDS? Or are they just saying funding pocket track has priority?
    .

    The real kicker here is saying there won’t be much use of the center platform, but that it won’t be able to handle the crush load without being much wider. Huh?

    1. exactly … the airport isn’t the only destination south of downtown that people might want to get to/from East Link on.

      as for the platforms … as I said in my post above … the roadway is 4 lanes wide … converting two of them into a center platform has to be as wide if not wider than the existing side platforms.

      Sure it might cost some $$ to add elevators/stairs to the center platform … but the IDS station outdoor plaza is designed with lots of openings to which an elevator / stairs could easily be attached to with limited changes to the architecture.

    2. Indeed, none of these arguments against a third center platform make any sense. IDS has Big Open Space on top of it, if you want to put in an elevator or just emergency stairs; the space of two bus lanes is very much wide enough for a wide platform; and *adding* platform space can’t possibly create crushload problems. Seriously, doors can open on both sides at once.

    3. Fortunately, Rainier Valley riders will have the option of taking the 7 to Rainier Station. This is not as ideal because it’s bus-to-rail, but if the transfer at Intl Dist is the worst of any city in North America, Metro may have to support Rainier Station more than it might like, with both the 7 and an MLK route (which might be numbered 42).

  7. Ah, I see Bruce (and others) are hearing the wrong question. They’re thinking about the cost of replacing the outer platforms with a center platform, as opposed to *adding* a center platform — as evidenced by the crushload argument. (There is no crushload period for airport trips.)

    So, when you hear about requirements for extra elevators etc., maybe they mean those will be required if a center platform replaces the outer platforms. We have to ask more specifically what safety features are required on a center platform whose only purpose is transfers between East and South Link.

    1. Bingo. Be very clear that we’re talking about a *third* platform, with all three remaining open.

  8. Keep in mind the tunnel originally opened in the early 1990’s and this includes ids. Also a train stops every 10 minutes during most of the day (varies during rush hour and late night). So what value would it be tearing up this station and possibly closing the tunnel for a couple years to solve this problem?

      1. Yes, he is suggesting that. They have some crosswalks like that on Boston’s Green Line. There’s one in Park St. Station, no less.

      2. Where are the crosswalks in relation to the trains, and how many of them are there in a typical station?

      3. The crosswalk is actually obstructed by the train when it’s stopped in Park St. station, an odd choice. There’s exactly one in Park St.

        In most stations with crosswalks they’re at one end of the station, picked to ensure visibility from arriving and departing trains. Which are going very slowly. Crosswalks “in front of” stopped trains are preferred from what I can tell. If you have to cross two tracks at once you can’t do that.

        Though Seattle has enough room in the two bus lanes (once the buses are removed) to put *both* crosswalks “in front” of the trains if a center platform is built.

  9. “Our long-term ridership projections put Eastside > Airport travel at about 3% of daily ridership.”

    Sounds like Sound Transit plans on eliminating the relatively quick Bellevue to Seatac route 560 when East Link is is up and running, forcing people to take East Link to downtown, then transferring to Central Link to the airport. The 560 takes 47 minutes for that trip. I’m estimating that the same trip on the combined East/Central trains will take 1 hour and 35 minutes.

    1. My bet is they’ll be able to get the 560 down to a more reasonable 30 minutes because it will only have to stop at Kennydale and Renton TC. East Link from DT Bellevue to Seatac will be about 1 our travel time plus your transfer penalty. A nice late night back-up.

    2. Sam – I think you are grossly exaggerating here. Travel time from Bellevue transit center to the airport via 550->Link today is scheduled at about 1 hour 5 minutes. Unless Link is expected to be 30 minutes slower than the 550 getting from DT Bellevue to DT Seattle, your numbers are just plain wrong.

  10. Center platforms are nice and all, but, the outside platforms work just fine in Chicago… I can only think of a couple transfer stations with a center platform, but otherwise its all outside, and it seems to work pretty well for me. I guess I’m just saying it doesn’t really matter that much in my opinion, as long as we have a train to get somewhere on!

    1. Where are the transfer stations? Do the trains open doors on both sides at these stations?

      1. Chicago has a couple of types of transfer stations:
        (1) Completely separated lines;
        (2) Four-track stations, with one line “outside” the other. These have cross-platform transfer.
        (3) Subway stations, which have center platforms;
        (4) Loop stations, with outside platforms, where the transfers are often very inconvenient; but at least all the stations have mezzanines inside fare control.

      2. Though transferring to the Red Line at State/Lake requires leaving the system, descending a staircase down to street level, then descending another staircase into the State Street Subway. It’s quite annoying.

      3. Trains never open both sides in Chicago, the most common transfer station is 2 tracks with outside platforms and a skybridge over the tracks or a mezzanine under them (but above the roadway)
        The north side has 4 tracks, 2 platform transfers where if you are continuing in the same direction on a different line you don’t change platforms(usually people transferring from local to express trains), if you are changing/reversing direction onto another line (say sb brown to nb red) you change platforms. (I do think the amount of people changing directions is minuscule though) There are many transfers that you have to leave and re-enter the system for, and those are just dumb, but, they work more or less.

      4. @Alex, I sometimes transferred from Red Line southbound to Brown Line northwest bound at Belmont along with several others so I think there’s more traffic going those directions now. The station revamps at Belmont and Fullerton stops means transfers happen by going down to ground level and back up to the other platform. The overpasses were eliminated at those stops.

  11. “that could accommodate the crush loads ”

    What is your definition of “crush load” on one Link light rail car? And when have you ever witnessed this?

    1. I see this at rush hour almost every day … and whenever there is a sounders game or seahawks game … train cars are packed to the gills with people standing

      1. That is not “crush loaded.” People standing is considered “normal capacity loading.” Link cars are designed to accomodate about as many standees as people sitting. That is NOT “crush loaded.”

        Just as I suspected, the people on this blog don’t even know what “crush load” means.

    2. I know this whole thread will get deservedly OTed in a moment, but, yes, Norman, there have been trains that were packed after games. There was actually no more room for passengers to get on.

      1. And of course, my question is, which neither of you have answered, is now many people were on the cars when “there was no more room for passengers to get on”? That is the entier point: HOW MANY PEOPLE can fit on a Link car before there is “no more room for passengers to get on?”

        And just because people refuse to board a light rail car, that does not mean that that car was anywhere near “crush loaded.” People refusing to board a full light rail car does not mean that car was “crush loaded” or even close to it.

      2. This subject is not off topic whatsoever. That author allulded to “crush load”. How is it off-topic to ask for his definition of “crush load.”?

      3. We’re talking about the relevance of ST’s argument that a center platform at IDS can’t handle a crushload. You’re the only one talking about a crushload on trains.

      4. Direct quote from Martin Duke in the article:

        “•Fire/life/safety codes make it difficult to fit a wide enough center platform that could accommodate the crush loads we see at rush hours, much less game days”

        So, I am the only one talking about “crush loads we see at rush hours, much less game days”? That is a direct quote from Martin Duke.

        You don’t think it’s relevant in determining how wide a center platform would have to be to accomodate a “crush load”, to figure out how many people a “crush load” actually is, and whether or not Link trains ever actually achieve “crush loads”? You don’t think that number is relevant to the discussion of how wide a center platform would have to be?

        Seriously?

      5. If someone gets pushed off the platform unintentionally, due to a large crowd taking up all the room on the platform, and ends up under the wheels of a train, it is a crushload. Thanks for the question, Norman.

      6. http://www.flickr.com/photos/51332149@N02/6229077068/

        Here is a video of a Link train boarding passengers at International Staion after a Sounders game that drew over 50,000 last year. As you can see, there are people left standing on the platform while the doors of the front car are still open. Other people who were planning to board the front train, run back to get on the back train even while doors on the fron train are still open.

        This strongly suggests that these poople who wanted to board the front train, but either ran to the back train, or just stayed on the platform and waited for the next train, considered the front train to be “full.” At least too full for them to board.

        Running this video in full screen and slow motion, I count approximately 130 people boarding the front train. Having seen several trains enter this station in the 45 minutes before this train, I counted no more than 10 passengers in the front car as they entered this station. So, I believe there were no more than 10 passengers in the front car when it entered International station.

        Therefore, the fron car was considered “full” by people who refused to board it, when it had appproximately 140 passengers on it. And this was after a large sporting event, when “capacity” of Link cars is higher than during normal commutes.

        So, here is some video documentation that the actual “event” capacity of Link cars is something like 140 passengers/car — not even close to the 200 that ST likes to claim.

        Therefore, a central platform would not have to be as wide as ST woul have everyone believe.

        So, there is your answer, also, Brent. You are welcome.

      7. “Crush loads…” was a quote from Bruce Gray, Norman, not Martin. Why don’t you email him and then you would have an exact answer straight from the horse’s mouth.

      8. Norman.

        I feel sorry for you that you have to take everything so absolutely literally.

        Sure … in controlled conditions I am sure that Sound Transit or Kinkisharyo got 200+ employees to cram into a Link LRV to test THE MAXIMUM number of people that could physically squeeze inside at one time.

        Thing is … in THE REAL WORLD we don’t act that way … people want some semblance of space around them … not to mention they are wearing coats, may have bags, are fatter than those in the test, etc … that all takes up room.

        Just because only 130 or 140 people managed to fit doesn’t mean that it isn’t crush load … that term is used for when you cannot get anyone else into the car … and that can be the case even if there are less that the potential physical maximum managed in a controlled situation. This isn’t Tokyo where we have station personnel forcing people into the cars so the doors can close … we wouldn’t accept that.

        Regardless … ST was referring to the masses of people on the platform. When there are too many like in that video it becomes a potential danger to those in the back pushing on the ones in the front.

        That is what they don’t want to have happen on a center platform between TWO moving rail lines.

        A good analogy is an old school phone booth. Sure college students crammed 20 of themselves or so in one … that doesn’t mean that crush load for a phone booth is 20 or so people … 2 or 3 can be enough for that space to be considered the equivalent of crush loading.

      9. Gordon, I feel sorry for you that you don’t understand that ST continues to use 200 as the capacity of one Link light rail car, when they calculate the number of people per hour per direction Link can carry.

        Don’t you get it? Using 200 as the “capacity” of a link car, as ST continues to do, is an utter, complete, lie.

        Do you grasp this now, or not?

      10. “ST continues to use 200 as the capacity of one Link light rail car, when they calculate the number of people per hour per direction Link can carry.”

        They use 148 in all of the recent planning work for the Lynnwood and Federal Way extensions. Not that you actually care, but I thought I’d put it on the record.

      11. The actual capacity of a Link car, using the North American standard of 2 standees per square meter, is 132, not 148. So, ST is still exaggerating the capacity of its Link cars during normal commutes.

        But, what capacity did ST use for Link cars when studying the capacity of Link in pphpd over the I-90 bridge?

        What capacity did ST use for Link cars when comparing the capacity of the downtown tunnel with light rail versus buses, when it decided to replace all tunnel buses with light rail?

        Not that you actually care, Zed, but I thought I would ask you, anyway.

      12. “Several people chose not to board, presumably because they considered this car to be full.”

        Or they saw less full cars and went to board those. If all the cars were that full they may have boarded anyways.

  12. Why not just make a third platform in the middle while keeping the original two? The trains could pull in an open both doors letting people cross the middle, or go to either of the side platforms. People boarding from the surface could go to either the north or south platforms, or take a third escalator (or even elevator only?) down to the middle platform. This would solve the transfer problem and create more platform space. There is a station like this on the Nankai line (Izumisanno Station) going to Kansai airport in Japan, it works quite well.

    1. Thanks for confirming that we weren’t explicit enough in describing our desire to add a third platform in the center of IDS. ;)

      What safety/access features are there on the center platform on the Kansai line?

      1. BTW, it should also be made clear when you’re talking to Sound Transit that this change (the third platform) could *only* be made after the buses are “kicked out” of the tunnel, so that’s the planning/funding timeframe.

    2. Heck, if the center platform is intended for transfers only, it probably only needs a crosswalk for escape purposes, as a minimum construction. Additional elevators or even stairs are “icing on the cake”. If the crosswalk is considered unsafe, a set of exit-only stairs would be the minimum.

      1. unfortunately …

        I would imagine that the issue would be this (pretend there is a center transfer platform):

        NB train at station … center platform full … SB train arriving.

        NB train magically catches on fire … SB train still moving … people, those averse to being on fire, panic and jump in front of moving train and get smushed.

        lawyers say no more central platform due to lawsuits over the lack of an escape route other than jumping in front of another moving train

        don’t like the fire analogy? how about a person with a gun shooting at another person because they did something like look at them or bump into them by accident or some other idiocy like we have seen as of late … same panic … same injuries … same lawsuits, etc …

        This isn’t to say that stairs would prevent lawsuits, injury, etc … but I could see how the lawyers might nix the idea without them

      2. What lack of escape route? The stations are long enough to put crosswalks beyond the end of where the trains stop, so that everyone can flee in front of the moving train and not get smushed.

        Extra stairs wouldn’t hurt, obviously.

      3. @Gordon: Your hypothetical scenario would be true of any center platform station regardless of whether there were additional outside platforms. As long as there was a potential route for escape at one end of the platform there would be no problem. Thus, I don’t see that as a valid concern even by legal standards.

      4. hey … it rains … people fall on the bus and sue metro because it’s metros fault the floor was wet …

        just bein a cynic. I am all for center platform at IDS … been bugging ST about it since East Link was first announced (actually first I was bemoaning the lack of planning for a 3-way junction so East Link trains could head south too)

  13. How about a tunnel concourse, like at LA Union Station that has ramps up to the two platforms, continues under Union Station and the BNSF rail line, with a ramp up onto the sounder platform, and terminates with a ramp up onto trackside at King Street?

    Yes, I know: engineering nightmare, blah, blah, blah, etc, etc, etc. but pretty small potatoes compared to the GN or deep bore tunnels. Plus, it would address a lot of Sounder and Amtrak transfer problems.

    1. Very pricey. At LA they built the “tunnel” first and then put the tracks on top of it. In Seattle the tracks are already there, so you’d have to go under them, while keeping them operational.

      I keep thinking that an overhead transfer corridor would be best, though it would still be pricey. But why not drop elevators directly to each platform from a high corridor?

      1. Wouldn’t that have to be a really high corridor, at least if you want to get to King Street? You’d have to clear the Union Station complex – or at least pass through it.

        When they rebuild the elevated part of Fourth Ave between (roughly) Dearborn and Jackson, there will be an opportunity to improve that transfer. I hope the take that opportunity.

      2. Yeah, you would have to pass through Union Station. Consider that an opportunity. :-) People like walking through nice architecture…

        Anyway, I agree with you, they should be able to make some improvements when they rebuild the elevated portion of 4th Avenue. Someone should campaign to make sure that happens….

    1. Hmm, once Seattle Subway is built, I’ve always liked the idea of a ring line (rather, a semi-ring line, like what St. Petersburg is planning): something like Alki-West Seattle-Georgetown-South Beacon Hill-Mt. Baker-Rainier-Central District-Madrona-Madison/East Capitol Hill-Capitol Hill-SLU-Queen Anne-Magnolia. Serves the areas east of downtown and the places bypassed by West Link. Alternatively, extend from Madison to UW, View Ridge, Wedgwood.

  14. Seems shortsighted of ST to always consider situations like this in isolation. The bigger issue is the cumulative effect of continually saying “close enough, good enough, not worth the cost/risk in this case.” The end result is risking a system that should be elegant and a pleasure to use becoming less efficient than it ought to be, perceived as cumbersome, and ultimately underutilized. Death, or at least a lack of vitality, from a thousand little cuts.

    1. Fortunately, ST did not succomb to putting Link on Eastlake or doubling the number of stations.

      1. Two more stations, yes. (Graham and 133rd.) Maybe a couple more on the extensions (especially 130th). But not stations every ten blocks, which would make it like the 358.

      2. (The 358 stops every 5 blocks, and it’s not even the stops themselves that cause problems. It’s all the shit that happens at the stops: slow payment, arguments with the driver, missing lights, and so on.)

      3. Fortunately, nothing can be quite like the 358. Entertained by fisticuffs just yesterday.

        Graham is the big hole. There should also be another station in CH, closer to Pike/I-5. Densest neighborhood north of San Francisco and west of Chicago merits more than one train stop.

      4. Transit spacing in Seattle is like Goldilocks and the Three Bears, but without the “just right” third option.

        We can’t consolidate bus routes that are 2 blocks apart. We can’t consider eliminating any of the roughly seven dozen Capitol Hill bus stops. But when it comes to actual rapid transit, “one is enough.”

      1. Same here.

        Imagine if we had stops at Madison/Boren, Broadway/Pike, Broadway/Roy, 10th/Boston, Eastlake/Harvard, and Eastlake/Campus Parkway.

        Link might actually be useful for going somewhere that’s not downtown…

  15. Getting to the mention of Seattle Subway, skulls it use the current tunnel or would it have a parallel tunnel on second?

    1. The max. capacity of the DSTT is something like 20 trains per hour. We’d already be getting close with U+North+East+South Link without buses, so there’s no way to accomodate trains from a West Link or Aurora Link. If it’s done right there should at least be underground transfers at each station; they’re already extending the Westlake mezzanine to the west under Pine Street.

      1. Your way off, like 50%. Max headways are 90 sec, per ST, with 30 sec dwell – so 2 min, not 3. That’s 30 trains an hour, each way.
        No need for another tunnel. Ballard trains can merge with North trains at CPS, just like the east trains will merge with ones from the south.
        Simple!

      2. Well, there’s not going to be a CPS anymore (wasn’t there a long discussion about this here?). There was a discussion of this here.

      3. Even the report here, which is more critical of introducing light rail to the tunnel, writes 2.5 (page 50). You’re right, Sound Transit says 2.

        But really, every 6 minutes Northgate-Bellevue + every 6 minutes Northgate-Airport + every 6 minutes Ballard-West Seattle is every 2 minutes altogether already. And that’s assuming nobody has got to merge at the entrance to the tunnel.

      4. Except that there’s no plan to run every six minutes on the airport line, or every six minutes on the Bellevue line.

        Ever.

        “It’s impossible because… I just made up some numbers that make it impossible!”

      5. Seems like d.p. and I have to debunk this “OMG, the tunnel is Full” argument every few months.
        Try this math – current trains are 8 min, 2 cars long running at half capacity.
        How much capacity is it with 4 times the headways(2 min), using 4 car trains, at full capacity?
        And the answer is 16 times more than today.
        Might as well ask for conversion of rural roads to 16 lane freeways while you’re at it.

      6. No, I did not just make up some numbers, except the 6-minute frequency on West Link to go with the 6 minutes that ST actually mentioned in a planning document. Besides, we are talking about trains per hour, not people per hour. Yes, doubling the length of the train doubles the “capacity,” but it decreases, if anything, the number of trains you can run per hour. The understanding is that trains will run every 3 minutes overall and that they will be four cars, which is not unreasonable, considering E, N, U link will all increase the ridership by about the current ridership of C Link.

        I again point to the fact that at both ends of the tunnel we have merging lines: E Link in the south, W Link in the north. Sure, 2 minute headways work fine in normal cities with subways, but there could easily be backups here with trains waiting at the entrances to the tunnel or at the stations, especially with the MLK segment’s unreliability not allowing us to perfectly follow a schedule.

      7. “Currently, the East Link DEIS operating plan summary suggests four car trains every 10 minutes in 2020, with headways down to every 9 minutes in 2030.”

        https://seattletransitblog.com/2009/11/16/link-headways/

        Cross-lake transit is inherently “commute” transit, whether the commute is for work, play, or family visit. Unlike some urban transit spines, it does not and will never demand greater frequencies than this.

        Meanwhile, the lack of grade separation on Central Link also restricts its minimum headways. And with long-term ridership forecasts for Central and South Link never approaching even 1/3 of the projections for the U-Link segment, you are never going to see frequency greater than the current peak of 8 minutes (times double-length trains) there either.

        The combined and grade-separated segment, depending on your source, will aim for as low as 4-minute trains… by 2040. That’s still just 50% capacity nearly 30 years away!

      8. Mic’s link, page 24: “The section of the line from Westlake pocket track to Stadium pocket track is designed for a 90-second design headway,
        to enable an ultimate two-minute operating headway.”

        Page 49: “After the light rail line is extended north and train operations require sole possession of the DSTT, the signal system will enable trains to operate at 2-minute headways.”

        Yes, that means it can deal with mergers and still achieve 2 minutes.

        Trolley tunnels and pre-metros from Boston to Brussels to achieve much tighter headways than that, despite multiple merger points and decades-old signaling systems. Only when headways get down to about 75 seconds do they really start to back up or have problems.

      9. “Cross-lake transit is inherently “commute” transit, whether the commute is for work, play, or family visit.”

        All transit trips are commuting. The distinction between trips to work, or trips at peak hour, or longer-distance trips, vs other trips is artificial. For people who don’t drive, it’s all the same.

        The distinction of “commuter” exists only because there are a large number of people who are willing to take transit only in a few limited circumstances (only to work, or only to ballgames, or only to downtown, or only to Seattle Center). So the difference is really the people, not the transit itself. But if our goal is to get more people to make all their trips on transit, then the distinction diminishes and disappears.

      10. Missing the point, Mike.

        Impromptu journeys will never be as likely to happen across the lake as they are to happen across town. Super-high demand is born of the former, as is the need for/desire for super-high frequency.

        This doesn’t happen on BART, it doesn’t happen on outer legs of the RER, and it won’t happen across Lake Washington.

      11. d.p., just as devil’s advocate, that sort of frequency IS needed and used across the river between Manhattan and Brooklyn, across the river between Manhattan and the Bronx, and across the river between Manhattan and New Jersey.

        Not that I expect Seattle-Bellevue to turn into the NY Metro Area, but it theoretically could.

      12. Nathanael,

        Believe it or not, even New Yorkers make inter-borough trips with less regularity and spontaneity than intra-borough, despite the subway’s awe-inspiring frequency and coverage.

        Your average Manhattanite or Brooklynite with a MetroCard may take as many as a dozen short- or medium-length trips within their primary borough every day, but they’re unlikely to cross the river more than once, especially without a compelling reason (work, school, show, errand of paramount importance).

        Because even with amazing service, far is still far! It still takes more planning; it still means blocking more time. Brooklyn residents complain about how months can pass without seeing their Manhattan friends — no different that Eastsiders who rarely hang out with their people across the lake.

        The only reason that the extremely high-frequency cross-East River transit you describe is needed is because we’re talking about 8+ million people, and hundreds of square miles of multi-use density, and myriad potential origin-destination pairs. Even with those inter-borough trips happening once a day or less, and even with them representing the minority of subway usage, they still add up to a hell of a lot of trips.

        But the principle (far trips = less impromptu than near trips) is actually the same.

        (Also note: At about 3 miles width, Lake Washington is 7 or 8 times wider than the East River. We’re not really comparing Lower Manhattan to Downtown Brooklyn here, or even Midtown to Park Slope. A Seattle-Bellevue trip is the distance equivalent of the Lower East Side to Coney Island, or of Times Square to Jamaica. Put in all the transit in the world, but it’s never not going to be far!)

      13. “The only reason that the extremely high-frequency cross-East River transit you describe is needed is because we’re talking about 8+ million people, and hundreds of square miles of multi-use density, and myriad potential origin-destination pairs. Even with those inter-borough trips happening once a day or less, and even with them representing the minority of subway usage, they still add up to a hell of a lot of trips.”

        Guess what, most Eastsiders try to avoid crossing the bridges because nobody wants to be stuck in traffic. So a lot of Eastsiders work on the Eastside. But even with that, the bridges are still full because there are still a lot of cross-lake trips. Just like in New York only on a smaller scale. People do not think, “The lake is three miles wide, so I’ll go to Seattle 1/7th the time that I would go to Manhattan.” When you have physical barriers, as in Lake Washington or Beacon Ridge, then transit just has to go across them without stopping. That doesn’t mean you should penalize people who are making cross-barrier trips and make them wait half an hour because the trip doesn’t meet with your approval.

        But I don’t want to get caught up in cross-lake trips because that’s only one small aspect of our region. My point is that there’s not really any difference between Capitol Hill-Northgate trips, Rainier Valley-UW trips, and Bellevue-downtown trips. Today I am going from Capitol Hill to West Seattle to walk the Duwamish Trail. Is that a “primary borough” trip or a commute? Or perhaps Seattle’s primary area covers a larger part of the city and burbs because Seattle is smaller than New York and has less destinations in a mile radius so you have to travel further.

      14. Mike, dude, why do you insist on arguing against facts on this particular matter.

        New Yorkers have unblocked access between boroughs. Bay Area residents have an unobstructed TransBay tube at all hours. People from the fringes of the Île-de-France have fast & frequent service into and across Paris.

        They still don’t take longer trips with the frequency that people take shorter trips!! They’re simply different beasts.

        You know that I do support East Link, right? I’ve never once voiced an opposition to it. It makes a hell of a lot more sense than Everett or Federal Way, because both sides of the lake already contain a lot enough mixed-use activity to create bi-directional demand, and because 10 miles is still more reasonable for rapid transit than 30 miles.

        And yes, the available of a “stable” supply of transit will marginally increase demand. Even I would see my elective Eastside trips rise from “never” to “occasionally.”

        But that 520 and I-90 traffic you describe is not evidence of the super-high demand you think it is. The physics of highway lanes are such that they slow to a crawl that cascades for miles the moment you squeeze one too many cars in… and that number is not very high. The current 520 has an design capacity of 65,000 vehicles per day, and is hell at 40% above that. There are no “millions” trying to go back and forth across the lake.

        Nobody needs 5-minute cross-lake service. And if it were available, it would be terribly underused. The round-the-world precedent does not support that kind of service for longer distances. You’re just wrong on this, man!

      15. I never said five minutes. East Link will be just fine at 10 minutes; that’s 33%-300% better than the 550. And while one person is making a 15-mile trip; three other people are making overlapping 5-mile trips. If you eliminate the 15-mile trip, you eliminate the 5-mile trips too.

        What is the limit of a “primary borough” trip from Brooklyn?

      16. Well, 9-10 minutes is what East Link is offering as its minimum. So we’re on the same page. This sub-thread started with a claim that the DSTT was full, partly because 6-minute East frequency was promised and/or needed (truth is neither).

        Limit? I said “primary borough” rather than “home borough” because many may commute to Manhattan once per day, then make many intra-Manhattan trips, even if they live elsewhere. But just as many live in Brooklyn and rarely leave it for any reason.

        “Brooklyn” is not a neighborhood like “Wallingford”. It has a land mass of over 70 square miles (Seattle has only 83); it has a population of 2.5 million. It would be America’s fourth-largest city if it were independent. There is no limit to the number or type of trips that are taken within it.

      17. I’m not commenting on the DSTT’s capacity because I’m not an expert in that area. What I care about is maximum 8-minute headways on downtown-Northgate, and maximum 10-minute headways throughout the rest of the network. (15-minutes acceptable after 10pm.) None of this 15-minute baseline (as in MAX) or 30-minute baseline (as in VTA) — that just starts to make the transit system less effective. As to whether all the lines can fit into one tube downtown or two, I don’t care, I’ll wait till that number of trains becomes a real possibility.

  16. Wait! Why would there need to be any escalators or elevators to this center platform?

    It isn’t for patrons entering or exiting the station; it is only for persons changing directions. No need to accommodate crush loads either.

    And can’t a turnback track be built in the soon to be former staging (switch from diesel to trolley and back) area?

  17. This seems like an easy problem to solve. Make the platform for transfers and exits only, and just put in a simple set of stairs and an elevator for ADA. There seems to be plenty of room at IDS for an elevator, it’s mostly a big empty plaza. If it gets too busy during game days, for whatever reason, they could simply temporarily close the platform and not open the doors on that side. It would at least give the security guys something to do for a while.

    I also don’t understand why they would ever need a pocket track there. There’s one at Stadium Station and a crossover east of Westlake, it seems like that should handle and operational needs. If they really need a pocket track, can’t it just be build in the bus layover space south of the platforms? It seems like they really didn’t put a lot of effort into trying to make this work, and are just coming up with excuses.

  18. don’t forget that elevators and escalators seems to be out of order in some tunnel stations. That will make the problem worse for that transfer. I guess the only issue I see, if a ADA person had to evaluated from the center platform in an emergency. I don’t see ever a reason for a pocket track there. Hope ST does revisit the issue once East and South LINK operates.

    1. Adding an elevator or two on each side would presumably cost much less than reconfiguring the station, and would at least mitigate the situation. Another would be to install a second escalator on each side, so that the escalators go both ways rather than only one way.

      Re escalators, I saw something extraordinarily stupid at Westlake. The two “up” escalators at the Nordstrom exit were being repaired, and yet the working escalators were still going down rather than up. I saw that at a longer platform escalator too somewhere, which only had one escalator and a stairway, but the escalator was going down rather than up. Isn’t it self-evident that if there’s only one working escalator it should be going up, regardless of whether it’s on the right or the left side?

      1. Are they actually reversible escalators? Some designs aren’t capable of running backwards.

      2. Actually, pouring concrete for a center platform, and adding to that platform one elevator and one flight of stairs, would almost certainly be cheaper than adding “an elevator or two on each side”.

        We’re talking about dropping two shafts from the surface, one for an elevator and one for stairs, and then pouring some concrete to elevate an existing concrete floor. Unless there is something really odd about the structure supporting the plaza above International District station, this is a relatively easy project.

        The three-platform structure would then provide LOTS of capacity for passengers to avoid crush loads. You could even use the “Spanish Solution”: make the center platform exit-and-transfer only. Open the doors on the center platform first, encouraging everyone to exit that way, and then open the doors on the side platforms, encouraging everyong to enter from the side platforms (except for transferring passengers). The people-moving capacity would be enormous.

      3. And reminder to anyone in Sound Transit reading this: any of these proposals apply *only after the buses have been removed from the tunnel* so that the center lanes are unused.

      4. More on why it’s called the “Spanish Solution”: quite a few metro stations in Spain use the design of having separate “exit platforms” and “entrance platforms”. It’s actually much older than the Spanish metros, and there are a few places in the NYC subway which were designed this way. LIRR also opens doors on both sides at Jamaica. (There, people *walk through* the trains to get to connecting trains, which is a little crazy, but efficient.)

  19. So, if ST really does grasp the concept of a third central platform in IDS (which appears not to be the case), and really is concerned there could be a crushload of passengers heading north from Stadium Station, and then transfering to East Link to head home, then there is a rather simple solution: Close down the center platform during post-game operations. Don’t open the inner-facing doors of the train in IDS.

    Or, if it isn’t too complicated, don’t open the west doors on northbound South Link trains, and don’t open the east doors on eastbound East Link trains, which would still allow the small handful of passangers rushing to the airport to make the transfer.

      1. I’m not closing anything. ST would make the call on whether using the center platform during a particular peakload creates too great a risk to passengers.

        My point is that building the center platform doesn’t obligate ST to use it at all times trains are running. Ideally it would be used at all such times, but ST could close it for safety concerns.

        The possibility that such events will happen is a majorly lame excuse not to build the center platform.

      2. But wouldn’t the crushload be twice as heavy if one platform is open rather than two?

      3. Bring this up with Bruce. He’s the one relaying the nonsensical arguments about a piece of architecture, er slab of cement, that ST hasn’t actually contemplated.

    1. Cemter Platforms work great where there isn’t a lot of people taking the train. Late at night when the Paris Metro isn’t very busy I welcome center platforms but when it’s really busy they’re a mess. The only center platforms that work well are the really wide ones with a wall in them (ie. Les Halles). I agree with ST on this one. Now if the trains were on the outside of the tunnel opening and the entire unused width including the two side platforms now was used you have something.

  20. decades from now, riders will wonder “what were they thinking?”

    Decades? Hell, I think that now.

  21. Based on projections, 3% of trips will be 1,500 trips per day. Let’s say that it requires 2 minutes on average to get from one platform to another.

    That works out to about 18,000 hours per year of wasted time, the equivalent of sending a single person on a two year walk between platforms.

    Some (me) would call that disrespectful.

  22. DC’s metro has some stations with center platforms, and some without – of all the complaints I hear about DC’s metro (of which there are plenty, http://www.unsuckdcmetro.com), NEVER does anyone complain about a given station, lacking a center platform. The same goes for the NYC subway. In my humble opinion – let this one go – it will likely end up being the least of Seattle transit riders’ worries soon enough.

    1. The issue at hand is not whether *all* stations have center platforms, but whether transfer stations, where lots of riders change lines, have center platforms. That is, how easy is it to get out of a subway from, say, Brooklyn, and get right back on one going to, say, the Bronx?

      In particular, C/IDS is the *only* station in the Link system (as currently designed) where riders are expected to transfer between lines. East and South Link share the same path north of downtown, and then diverge once they head south/east from C/IDS.

      We’ve got twelve years for ST to figure out how to lay down a slab of concrete to have essentially direct train-to-train transfers without needlessly going up and down a set of stairs/elevators. (There are no down escalators.) I think we can figure this one out in that amount of time.

      1. But for DC this still doesn’t apply. I’d guess that the majority of transfers (at least the majority I did when living in the DC area) are from one tube to another. so were inherently grade separated.

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