Avgeek Joe
Avgeek Joe

With the confluence of Mariner and Husky season looming, Mike Lindblom reports that Sound Transit is looking to beef up “mega event” service beyond it’s already-boosted weekend standard of 3 cars every 10 minutes. Sound Transit would do this by running weekday peak frequency but inverting the baseline, with twelve 3-car trains joining seven 2-car trains. During regular peak service today, twelve 2-car trains are the baseline, supplemented during peak by seven 3-car trains.

Much has been made of Link’s railcar shortage and ability to run longer trains for events. Though the opening of Angle Lake Station on September 24th will not change schedules or frequency for existing stations, it will add one new trainset to the rotation, reducing Sound Transit’s flexibility further. Prior to the delivery of next  generation railcars in 2018-2019, Link has only 62 railcars, and Sound Transit is wisely being conservative about lifecycle maintenance. A Board report last month showed that while Link is sometimes uncomfortably crowded, the current service provision is running well within capacity limits.

In a fleet of 62 cars, our current peak service uses roughly 77% of our railcar capacity (48/62), weekends use 58% (36/62), and weekday off-peak uses 39% (24/62). Sound Transit’s “mega-event” proposal would stretch utilization to its furthest yet, or 84% (52/62). And this is just my calculation based on active service needs. Allowing for layover, padding, and operator breaks further reduces flexibility.

What’s the most Sound Transit could possibly do? Before the 2018-2019 delivery of new rail cars, Link’s maximum capacity would likely be 3-car trains every 6 minutes for 97% utilization (60/62). So at 84% utilization, it’s clear that with this weekend ‘mega-event’ proposal, Sound Transit is taking the issue seriously and will stretch its fleet within reasonable maintenance limitations.

Link Railcar Capacity

When these big event days are on weekends, Sound Transit has more flexibility due to the availability of bus-rail tunnel slots in the Downtown Seattle Transit Tunnel. Were a massive convergence of events to happen on a weekday, when tunnel bus commuters still need reliable service, I’d suggest that Sound Transit look into a different “tunnel maximizing” level of service. Because every Link train takes up one tunnel slot – buses and trains are prohibited from sharing a platform – maximizing weekday tunnel capacity would involve running longer trains at lower frequencies. 4-car trains running  every 10 minutes would provide the same capacity as our current peak service, while using 33% fewer tunnel slots. 

What do you think? When large events occur on a weekday, would you rather have higher frequency, even if it meant more tunnel delays? Or would you rather have more reliability, but a longer wait?

94 Replies to “Sound Transit to Boost “Mega-Event” Link Capacity”

  1. Fewer, longer trains would be better … But only if they have realtime next train signs… Which we should have had since 2009 but do not

    1. I really disagree. Frequency is IMHO one of the most important parts of making Rail usable. If Link is the ONLY part of the journey that you need to take then a 10 minute frequency, but when it’s the middle leg of a 2 or 3-seat trip (as it is for many people today, esp. with increasingly forced transfers), a wait time of up to 10 minutes is just unacceptable. Since on a 2 – 3 seat ride you have no control over when you arrive at the station, it’s not like you can just make the schedule. This is especially egregious for shorter trips – for a 30 minute journey to turn into a 40 minute journey is just deeply frustrating.

      1. As a suburban transit rider who sometimes has a 4-seat ride from my house to my destination if it’s north of UW, I agree with this. Part of the deal with Link truncation, longer link travel times for longer-haul freeway trips, and forced transfers is that Link becomes so frequent that it’s a “show up and wait” kind of deal.

        When it runs every 10 minutes, then the important bit to me is train reliability in terms of schedule adherence. I often do trips from Link to a half-hourly route to an hourly route, so I like to have a specific time that I must be at the Link station to make it home on my itinerary. The 10 minute frequency doesn’t bother me much because if the transfer window seems too small, I can leave 10 minutes earlier, and 10 minutes isn’t a bad waiting time, especially in comparison to sparse suburban night service.

      2. But how does Link ridership compare to bus ridership in the tunnel? I honestly don’t know, but that seems like a major issue. If Link s 90% of the ridership, then by all means, sacrifice bus reliability. But if not, then the larger, more infrequent trains mean that you can run the buses more often.

      3. One advantage of fewer, longer trains is that if they’re all four cars then riders can be told to wait anywhere on the platform, rather than having to guess if they’re going to get a 3-car train or have to cram into a 2-car.

      4. Personally, I agree with more frequency, even if the trains are bunched. I live in NE Seattle and I’ve found that the parts of the re-org most useful to me is the increased frequency.

        I’ve also been known to take the 41 in the DSTT, which is the poster child of bunching. If one can “depend” on bunching or use OBA to get a sense of the amount, the smart thing to do is to assume/check for a second or the third train arriving a couple minutes later, and not necessarily take the first.

        Plus stand where you expect the 2nd car to end. Doesn’t have to be precise. While you are walking toward car 2 or car 3, you usually have to wait for others to leave the train anyway.

      5. I agree in general — I think it is silly to prefer consistency over capacity. But in this case, you might decrease it. By having smaller trains more often, you have fewer buses (like the 41). This means that a bus that is often packed is less reliable, and simply fewer runs are made. This might be the price you pay (the 41 gets worse service so that the train gets better service) but I would like to see the numbers.

    2. I was just in SF and BART and Muni both announce train length a couple minutes before they arrive, and have the platform marked with where each car will stop. Why can’t ST do something similar?

    3. Wrong. More, shorter trains are always better than fewer, longer trains. I don’t know where you’re getting your info, but you’re wrong.

  2. Thanks for using my photographs.

    Highly recommend more frequency. I don’t like waiting for my next photo op or ride. Why buses and rail cannot coexist should be hyperlinked to or explained.

    1. Because trains can’t stop as rapidly as buses, three car trains take most of the platform, and buses have longer dwell times. They just don’t work as a single platoon.

  3. I’d rather have smaller trains run more often. This isn’t some long distance system where you potentially are crushed for an over an hour. I’d rather suck it up and be miserable but on my way than wait and have a seat.

    Trains, at least in the morning, are already Metro bus style unreliable. I’d love to see specific run on time performance. The northbound 7:26/7:32 trains from CHS are rarely on time.

    1. But you’re not going to be on your way because the smaller trains will be full and you won’t be able to board.

  4. If a big weekday event coincided with normal peak service, it would be an interesting opportunity for Sound Transit to test out a 4-car train in the rotation. I think that would be 13 two-car trains, 6 three-car trains, and 1 four-car train. Although, admittedly this boost would be very infrequent with out a larger commitment to four car trains which probably won’t happen until East Link in 2023.

  5. As long as we keep it at or under a 10 minute wait I say more reliable wins, I can plan against it. But I really want both reliability and higher frequency.

  6. The FTA requires reasonable spares, but for rail operations it has no strict guidelines.

    These spare requirements are for normal operations, and unusual events are considered to be just that in terms of the spares requirement.

    Also, while there are maintenance requirements, the Link cars are all fairly new. They shouldn’t yet require major rebuilding of traction motor exchanges or all that, which can require the cars be out of service for extended periods.

    Thus, for special events, this really isn’t too excessive.

    With the Rainier Valley and its 6 minute limitation, and limited turning locations, is higher frequency really that possible?

    1. That’s the reason for the pocket track at Stadium. Trains can run on the north 1/3 of the system more frequently than down Rainier. Lazarus has a post below about a “full time” Stadium to Stadium line. I’m not sure that makes sense for base period service, but as a peak hours overlay and certainly on event days it does.

      1. That doesn’t help matters at UW. I don’t think you could go much more frequent until there is more turning capacity on the north end. Since you live in Vancouver: have you seen what it takes to get the Lloyd Center MAX station into a turning station?

        Also, pocket tracks are typically used for when a train has to go out of service and needs to be stored on the line. They might now want to turn stuff around there.

        What you really need are a couple of three platform stations. Stadium could be changed.

  7. It’s really unfortunate how poorly configured the current Link fleet is. With a more open layout we could fit a lot more people in each train and it would be easier to move towards the back. We’ll be stuck with this mistake for years.

    I’ve also seen massive pyramids of luggage from airport travelers. They don’t have a choice so we can’t blame them but there’s got to be a solution somewhere.

    1. Remove seats, remove LOTS of seats. Keep all seats on the “balconies” and in the centre section, remove most of the rest.

      1. Lloyd, I’m pretty sure putting the whole center section to the existing spring-loaded aisle facing benches would let seating and passenger loads adjust to each other.

        Incidentally, in the raised sections, sand storage and the panel by the doors remove most of the under-seat luggage space. Leaving no room but laps or the aisles.

        Considering the danger of trapping the driver- think collision rupturing a gas tank- signs should look like a pirate flag with the “No Luggage in the Raised Section message in letters made out of little bones.


    2. “I’ve also seen massive pyramids of luggage from airport travelers. They don’t have a choice so we can’t blame them but there’s got to be a solution somewhere.”

      They do have a choice; it will cost them cash for a taxi, Uber, or airport shuttle. If someone is coming with that much luggage, c’mon. And well, if the average Seattle household is on the hook $100/yr, well, the traveler with the suitcases now shares in that.

      One of the helps (not a fix) is to list commute times and likely crushload events at the ticket/ORCA reader that would give the traveler some idea of what they face.

      1. That “traveler with the suitcases” is oftentimes a local. If you want to get luggage off of the train you need to give people a viable public transit alternative. Saying “just take a cab” is not acceptable.

      2. It doesn’t take a lot of luggage to cause a pile up on the train. There’s no convenient place to put luggage except the bike storage area (which quickly fills up) or under the seat, if you’re lucky enough to have room under there. The trains was built specifically for going to the airport so I don’t understand why you think people should be taking cabs.

      3. Perhaps we can agree on this – the train line was built to skirt the airport but the train cars were not specifically built to handle airport traffic.

      4. The trains are designed as if only eight people will have luggage, just like they’re designed as if only eight people will have bicycles. And they can be mutually exclusive if somebody puts luggage in the bike-rack area.

        Meanwhile a single flight has fifty to a hundred people, and there are a dozen flights an hour, and we’re supposedly encouraging those passengers to take Link. And we’re anticipating so much bicycle use that we’re building cycletracks. Are the cycletracks supposed to have only eight bikes every ten minutes?

      5. ST could reconfigure the bike/luggage area to have 2 bike hooks and replace the “phone booth” directly across from the bike hooks with shelves for luggage.

      6. Baselle, better suggestion. Have Sound Transit offer luggage delivery service directly to passengers’ hotels

        I think passengers with anything more one wheeled suitcase per person would be glad to pay something reasonable to have their bags waiting for them after they’ve spent a few hours around town “unwinding” from their flight.

        The business community might see enough benefit to help pay for the service. I think it’s also time for transit, taxicabs, and ride-sharing to start realizing that everything that doesn’t involve private cars is the same industry. And cooperate accordingly.


    3. I understand what happened. The fleet is configured properly for the early, low ridership. Remember single-car trains on the weekends? If ridership never took off, they didn’t want to be stuck with a bunch of unused high-occupancy equipment for detractors to call “gold plated”.

      1. Lack, I think it’s closer to say that our cars are configured to avoid the need for raised platforms at any stop.

        Early consideration was that, knowing the DSTT would run buses for years, a high floor bus meant complications and expense. Steering could have needed a guidance mechanism.

        We also knew our light rail service would need street-level boarding for decades. San Francisco MUNI has handled this problem by fitting cars with movable steps adjust between street curb level and raised subway platforms.

        In addition to extra cost of a non-standard bid, experience with fleetwide added mechanism probably convinced us not to do it.

        Perhaps most important, we knew cost of raising existing low platforms when DSTT rail service started. Starting with making joint use pretty much impossible. Every single elevator and escalator would have had to be replaced.

        Very good chance, though, that we’ll be able to get a 100% level low floor in a decade or so. A 60 mph electric motor takes a lot of space. But trend with everything electrical is to get smaller and more powerful at the same time.

        And Baselle, the reason LINK was built to pass the terminal at a distance was that by, 2009 we’d learned from eight years’ experience that trains needed to be able to help evacuate the terminal during a sudden clearance, rather than get stuck in the middle of it.


  8. During mega events it would be best to offer greater frequency because the platforms get so crowded that rider safety needs to be considered. Too many people waiting on the platform for too long could lead to a crush on the platform that could be dangerous for riders. Sweep the platforms as frequently as possible.

    But greater frequency also creates another problem at the terminals. There’s only layover space for 2 trains at each terminal. When the trains are running at 6 minute intervals that means that the actual layover time at each terminal can’t exceed 12 minutes, so it may be necessary to rotate drivers in order to provide breaks.

    Mega events also extend the trip time by a few minutes. During mega events the normal 44 minute trip from UW to the Airport may be a few minutes longer.

    1. It doesn’t help that Stadium station is about the worst possible design for a large influx of crowds. This is one of the places where an over built station would have made sense, meanwhile sleepy Roosevelt will have one of the world’s largest subway stations.

      1. Don’t count on Roosevelt being “sleepy”. I hope someone at Metro and Sound Transit is doing the math for capacity planning with regards to all the development going on around Roosevelt. I predict the Link cars will be full (or just about so) leaving Northgate, and when the hundreds of people in Roosevelt station want to get on they will be sorely disappointed that the train is already full. If not in 2021, then it will happen in 2023 when the Light rail goes up to Montlake Terrace and Shoreline.

      2. No doubt Roosevelt is growing. Maybe ‘sleepy’ wasn’t exactly the right word but the crowds in comparison to the Stadium district are obviously nowhere near the same level (and never will be). Yet Stadium station is a glorified streetcar stop while Roosevelt has a half-billion dollar palatial behemoth of a station.

      3. When Northgate and Lynnwood open the trains will be twice as long and come twice as often, meaning there will be 4x the capacity we have right now.

      4. It is really apples and oranges. The Stadium stop is one of the worst performing stops (the numbers are very low) because events don’t happen every day. In contrast, with increased density in the Green Lake/Roosevelt area, as well as some decent connecting bus service, you could easily have high all day ridership there (not at the same level as Capitol Hill or the UW, but still pretty high). But that doesn’t mean that ridership at the station at its peak is anything close to what Stadium will endure a half hour before game time (or 15 minutes after the game ends). Roosevelt is much more of a steady stream, while Stadium is a sudden, rare burst.

      5. @David — Yeah, it is a completely different situation (the buses will be gone from the tunnel, so that won’t even be an issue).

      6. How palatial is Roosevelt Station? Is it the size of Capitol Hill Station? Or more like Mt Baker or TIB? The platform length is fixed due to the 4-car train requirement, and I don’t remember if it has one entrance or two. (There was concern that a north entrance would be little-used.) So if it is like Capitol Hill, that’s reasonable. Roosevelt will probably have less ridership than Capitol Hill, but not difference enough to chop off part of the station.

      7. Jan is right. North King is paying for a gold-plated high speed commuter railroad to Snohomish County, and in the morning its riders will all be standees. Some trains should be turned back at Northgate in the peaks. Period.

      8. North King is paying for a…commuter railroad to Snohomish County

        It’s a shame ST didn’t employ sub-area equity from the beginning in the way it has started doing to fund the new tunnel downtown—on the basis of projected ridership by sub-area on a segment. Then Snohomish would be paying the bulk of everything on Central Link north of the U district and South King the bulk of everything south of Mt Baker. There would be a lot more money for North King projects. Now they’ve set this precedent, it can be used to North King’s advantage in the future.

      9. “Now they’ve set this precedent, it can be used to North King’s advantage in the future.”

        Do you have any specific places in mind? I’m afraid I can’t think of any, except for the airport. There’re always going to be more people going into North King than out of it.

    2. @GuyOnBeaconHill — The platform situation might get worse if they have more frequent train. There might be more people waiting for their bus (and they might be more ornery when their bus finally arrives) rather than a regularly scheduled, albeit infrequent, but at least very big train.

  9. More frequency with smaller vehicles is better. But based on ubstituting articulated buses for regular buses allowing for a reduction in frequency seeming to be KC Metro policy, it wouldn’t surprise me to see it happen. If the buses are crowding the tunnel then put them on the street before the plan says to.

    1. As I asked above, how many people take the bus, and how many people take the train in the tunnel? My rough estimate is about 40,000 or so take a bus through there, and roughly 60,000 take the train. So about 60% of the riders take the train. But I would guess that the buses are actually more commute focused than the trains. The trains now serve the UW, Capitol Hill, and the airport, three of the least commute oriented trips. So, during rush hour, it is quite possible that roughly half the trips are by bus, and half the trips are by train.

      In that case, sending the buses to the surface would be much worse than crowding the trains. There are plenty of buses that are crowded right now, and putting them on the surface will make things worse. That just sounds like robbing Peter to pay Paul.

  10. It’s interesting how much Link gets delayed due to peak buses since Link gets slot priority, i.e., it’s not Link that has to wait for a Link slot, but buses that have to wait for a bus slot (that’s why buses sometimes have to wait a few minutes before entering the tunnel. My guess then is that all of the additional delay is due to high bus dwell times at Link stations.

    I wonder if the current peak reliability problem could be mostly solved if we increased the expected dwell time at tunnel stations (for both buses and trains, so trains would stop longer too) by 30 seconds. That would make end-to-end Link trips longer, but the extra train coming with Angle Lake should make that a non-issue.

    1. Those tunnel-bus dwell times do slow Link down in the tunnel for sure, but they’ve been baked into the schedule from day one, and they’ve recently improved with the elimination of
      (formerly)massive-ridership U-district express buses.

      Link’s own newly-enlarged dwell times have been blamed by ST/Metro for the increased delays. Apparently it’s hard to account for the additional dwell related to SRO trains, with exiters slowly pushing their way off and boarders hunting up and down the platform for the least crowded door.

      But how bad is current reliability at peak? I’ve never tried to time a transfer to a particular 6-minute train, and I rarely ride the line full-length. How bunched are trains getting? How often do they layover at Mount Baker waiting for the clock, now?

      1. It can be pretty bad. A few weeks ago I was waiting for a southbound train at Capitol Hill, and I saw 3 northbound trains in 4 minutes (the one that picked me up was in fact one of those), so Link does sometimes suffer form RapidRide-like bunching. In that scenario, it’s possible that some were waiting 14 minutes for a train.

        Yeah, actual dwell times are horrendously difficult to predict, so that’s why they should take the data they have now, and set dwell times to the highest of the bottom 90% (depending on just how outrageous that is, of course). That way, only 10% of buses and trains will delay Link even a little bit.

        They could also strategically speed trains in U-Link tunnels. They are already strategically slowing trains down as they approach UW (they have to because UW can only hold two trains max), but it would be interesting to see if they can safely run trains slightly (but just slightly) faster than normal if they are falling behind schedule.

      2. ST could address the schedule reliability problem by rotating drivers at Airport Station. When a southbound train arrives at Airport Station a new driver would be ready to take over the train. The new driver then goes to Angle Lake where the security check is completed and then the train heads back north immediately (at the next 6 minute mark). The train then runs to Husky Stadium where it again turns after a short security check and heads back to downtown and the airport. Again, at the airport, a new driver takes over and the cycle is repeated. The complete cycle would take close to 2 hours and the relieved drivers would take their breaks at Airport Station and then get back in line for the next train.

      3. I’ve been commuting between Westlake and Capitol Hill on Link, and while the trip north usually takes 3 minutes every once in awhile we go blazing through the tunnel in 2. I don’t know if it’s coming from the control center or from a particularly lead-footed driver, but it does happen.

      4. The issue with switching drivers at the terminals is that drivers probably clock in and out at the maintenance facility, so drivers would probably have to be paid to take a (free?) Link ride to Sodo station, and probably have a metro shuttle or something take them back to the base.

        I don’t think it’s that disruptive to have a driver switch stop at the maintenance facility once every two hours.

      5. When trains are crush loaded trying to switch drivers at the O&M facility is just about the worst place to make the change. The car is packed and the extra minute or two that the change requires would slow down the traffic flow even more. Yes, it would take some extra labor hours to ferry the extra drivers to SeaTac Station, but drivers wouldn’t be taking their break on board an out of service train. The train would still be in service while the drivers were taking their breaks.

        Having the drivers switch at SeaTac Station would save at least one trainset from the rotation which would create 2 more 3-car trains.

      6. I think GuyAtBeaconHill is talking about driver breaks rather than end of shifts. If a driver took a 2- or 3-train break at SeaTac, that would be 20-30 minutes, and 15 minutes of that would be regular paid break time, and the rest would be layover delay like buses do to maintain 30-minute or 60-minute headways. Shift ends seem to happen at the base stop, or at least I’ve been on trains that have stopped there presumably for a driver change.

        What I can’t quite figure out is if a driver goes on a 2- or 3-train break at SeaTac, who will drive the next train out? Somebody else would have to finish their break at the same time, or idly ride down to SeaTac from somewhere to be ready for the next train (but not starting their shift, since there are not enough people starting a midday shift for this). Maybe it all works out in scheduling complexities but it seems like it could be a problem.

      7. Here’s a rough sketch of what would happen when Link goes into Mega-Mode. A couple of extra drivers would likely board at Sodo Station and ride the train to SeaTac Station. One of the extra drivers would then take over the train at SeaTac Station and drive it to Angle Lake. The train would only stay at Angle Lake long enough to perform the security check and wait for the next time slot before heading back north (likely about a 5 minute layover). The drivers who were relieved at SeaTac would head to the break area for about 15 minutes and then they would take over another southbound train at SeaTac Station and make a full round trip to Husky Stadium and back again to SeaTac.

        When Link is in Mega Mode it’s important to keep the trains moving and not have trains resting at terminals just to give drivers their needed breaks. Having one designated relief point would make the process much more orderly. SeaTac would be the best location because that stop is already a bit longer than other stops and there is at least a bathroom facility/break/security area there already.

      8. This is what LA Metro does. The operator schedules are posted on the Expo Line message board, but the driver always falls back at the terminal – they pull in the train and the driver previous to that one operates the train back.

      9. “A few weeks ago I was waiting for a southbound train at Capitol Hill, and I saw 3 northbound trains in 4 minutes… In that scenario, it’s possible that some were waiting 14 minutes for a train.”

        Something like that happened to me around Friday or so. Two trains came the opposite direction before my train come. And when I arrived at Capitol Hill a next train sign said “28 minutes”. Those may have been separate occasions; I don’t remember if it was the same trip. I remember thinking that if I was waiting for a train I wouldn’t know if the 28 minutes was accurate or not. Then I wondered how it would know a train is 28 minutes away, because if there’s no train before it there must be an outage and it wouldn’t be predictable when the outage would end.

        I have also seen outages where the signs at UW Station say “Departing to Seattle & SeaTac” but the time area is blank. That happened this morning when I arrived there, and I’ve seen it before. But it didn’t happen during the outage I was in a few weeks ago, where it just said “1 minute” and recycled to “10 minutes” cool as a cucumber while a hundred people were waiting, and then it got down to “2 minutes” again and several people said, “It’s coming in two minutes” and I had to shout, “Not two minutes. There’s an outage and no trains are coming. It says technical interruption and more information will come soon.” Even after that a few people muttered that a train was coming in two minutes, so they didn’t see the interruption announcement or hear what I said or understand it.

  11. For Husky football games in general, I’m not too worried about consist length consistency or platform crushes, as long as security limits the rate of station entry. The trains will be dwelling at the UW Station platform for a few minutes before departing.

    However, on both Saturday, September 17th and Friday, September 30th, the Huskies will let out about half an hour before the Mariners do. With trains taking 15 minutes to get from UW to Stadium Station, we may see an unusual phenomenon: third cars getting crushloaded.

    If crowds get backed up at Stadium Station, we may have the additional problem of keeping the tracks clear north of the station. Don’t let passengers end up blocking the box, because it will be hard to undo with crowds right behind them. Security at the north station entrance assigned to keeping the tracks clear could be essential.

    One favor ST could do for itself is to monitor how much of the Husky football crowd is alighting at each station after the first game. Don’t expect the pattern to resemble a school day.

    I generally side with consist length consistency so as to make full use of the deployed capacity, especially for the daily commute, but as we enter into new scenarios, safety needs special emphasis, especially at (Baseball) Stadium Station where people will be rushing to find all available pockets of space on the train in a matter of seconds. In that situation more frequent two-car trains do the job better than less frequent three-car trains.

  12. I wonder if we might get a test of all this on 9/30, Friday evening. There is a Mariner game that night against the As, and the Ms might still be in the playoff hunt at that point, meaning 40K+ fans could be in attendance. The Huskies also play Stanford that night, pitting two of the Pac-12 favorites against each other, which should mean a sellout at Husky Stadium. And it’s Friday night, with all the in/out traffic from commuters, people going out for the evening in Seattle, etc. The UW game starts earlier than the Ms game, but they could end right about the same time.

  13. There are a whole series of variations that you haven’t discussed in your table. Buses come out of the DSTT in 2017 or 2018. After that ST has lots of flexibility to provide high frequency service at levels of reliability that just can’t be achieved with buses in the tunnel.

    What is one of their concepts? Interlining a second line between Stadium and UW Stations.

    Adding this second turn-back line has lots of advantages. It allows high frequency, high capacity transit through the heart of the urban core without putting too many LRV resources on the periphery (South end of the RV, SeaTac, Angle Lake) where they would be underutilized. Additionally, the LRV trains operating on the turn-back line have short end-to-end transit times due to the shorter length of the line. This means that a smaller number of LRV’s can provide a larger number of total cycles.

    Such a concept could operate at 3-min headways north of Stadium Station and 6-min south of there, although other options are available. 2-car trains could operate on the turnback line and 3-car trains on Central Link, or whatever is required by the type and location of the events.

    Such a concept has lots of advantages and makes maximum utilization of the existing LRV fleet without wasting service hours where they won’t be used. It does require removing buses from the DSTT, which can’t happen soon enough, but will happen anyway in a year or so.

    1. Yes, I was only speaking about near-term possibilities under joint ops. We’ve written about the turnback concept at length, and I really hope they do it.

    2. Right now the real practical limit to frequency is the turnback capacity of the two track station at UW. It really doesn’t work well as a very frequent terminal station with two tracks. How much breathing room do you want to allow?

      If you choreograph this down to the half minute, a very minor delay quickly spreads to everywhere else.

      You don’t want to strand a train in the tunnel for any length of time.

      1. ST has been studying the concept and believes that it is doable with the current configuration of tracks at UW Station. All it takes is the courage to move forward and it could be done relatively quickly.

        The buses come out in 2017 or 18 anyhow. Just take them out now and let’s get on with it.

      2. I’ve noticed that trains consistently slow way down just south of UW in the crossover track area, after doing 55 most of the way under Capitol Hill. What’s up with the slowdown? Is this required for technical or regulatory reasons, or is it for schedule padding, or…?

    3. The turnback track could be used but it would be a complicated process. First, the train would have to be emptied of all passengers who mistakenly thought it was a thru-train. Then it has to undergo a security inspection and then maneuver into the turnback track. The driver then has to change ends and maneuver the train back onto the opposite track. And all of that has to happen within a 3 minute window.

    4. It would be great to introduce an interlined Stadium-UW service. Call it the “Blue Line” and say it’s a placeholder for East Link. Call the Rainier/Airport line the “Red Line” as planned and prepare the region to have multiple rapid transit lines for the first time in its history.

  14. Wasn’t there talk about a short line and a long line when the 550 has to get pulled out of the tunnel? I could see how it might be possible to run 3-car trains every 10 minutes to and from Angle Lake and overlay a second 3-car line that runs every 10 minutes to/from either Stadium north or to/from the light rail yards north – providing 5 minute frequency in the DSTT. Then you could pull buses out and provide layover space at Royal Brougham Way. How many cars would that take?

    1. Yes. This has been studied and could be done relatively quickly. Such a concept would provide up to 3-min headways in the urban core while retaining 6-min headways in the RV and points south. And it puts the LRV-hours where they are needed instead of at the far extremes of the system.

      It works, it is efficient, and it helps alleviate problems with the LRV shortage. All that is lacking is the political courage to make it happen.

  15. Frequency is freedom. I think 10×4 is too much of a headway. 3×8 would be acceptable, although the difference between 6 minute and 7.5 minute headways is surprisingly noticeable.

    But I think the status quo is better than these for most people, except for those on bikes.

    1. I agree, but I’m only talking about once-a-year mega-event weekdays. On those days, wouldn’t 4-car every 10 minutes be preferable to DSTT meltdown?

      1. Once a year mega-event? ST is planning for 2 such events just in the month of September! Band aids are fine, but it really is time to set the system up to handle this kind of load. Because such loads are already here and only to get bigger.

      2. Again, on weekends (like the 2 in September) they have plenty of flexibility. I was conjecturing about a hypothetical weekday with the same amount of event convergence, for which tunnel ops are more complicated and in which longer but less frequent trains might make sense.

    2. As I mentioned above, don’t forget the buses. By my calculations, they still carry around 40% of the riders in the tunnel. I would also guess a bigger proportion of the commuters (Link now serves Capitol Hill, UW and the airport, making it a lot less commuter based than most of the tunnel buses). It might even be the case that buses still carry half the load during rush hour. So less frequent, but bigger trains allow free flowing buses, which might be better overall.

      This is just a very tough transition period. It will get much better when we get to Bellevue and Northgate, and those bus routes become obsolete (and the trains carry a bigger proportion of the load).

  16. Could ST lease a few train sets from another operator to let them keep the current schedule but have all 3-car trains? I don’t know specifically where they could come from but there must be some extra spares somewhere because of a delayed opening or low ridership.

    1. ST has plenty of capacity, but the available LRVs don’t mesh with the frequency, so trains vary in length while scheduled headway does not, and pass-ups happen.

      A lot of the capacity and dwell-time issues could be solved if (1) ST had a way of announcing train lengths, and (2) 3-car trains could start off a little later than 2-car trains, to even out the loads.

      Since they have cell service in the tunnels now, security at CHS ought to be able to call ahead to boarding assistants at Westlake, who could write 2, 3, or 4 on a dry-erase trifold.

      1. 3-car trains could start off a little later than 2-car trains, to even out the loads.

        This would make so much sense. The 3 car trains would only have to depart 1.2 minutes late to even out the capacity – the 6/6 headway becomes 7.2/4.8, 12-minute ridership is split between them 3/5ths to 2/5ths.

        But such a small change would probably be lost in the randomness of operation.

    2. Won’t happen. All, or virtually all, other light rail systems use 750V overhead power, and ST is 1500V. Trains are incompatible. Not to mention likely incompatibilities with signaling, communications, etc.

    3. If we could lease cars from another municipality, I assume the transportation costs to get them here would be non-trivial.

      But neglecting that for the moment, any such leased cars would have to be built for a 1500v system, and most other light rail in the nation is 750v. According to wikipedia, there’s only 2 other agencies running 1500v in the US, and from glancing at pictures, I don’t think either’s equipment will fit in our tunnels or match to our platform heights.

      1. The only part of the system that is 1500v is the static converter on the roof. That is less of a fixed value than you might think. TriMet’s “750 volt” overhead has been set to closer to 950 at some of the substations.

        The static converters may even come with different taps so that all you need is to connect a different jumper. I’ve never seen the insides of one. It’s mostly just a bunch of large power transistors that adjusts itself to produce a constant output with a widely variable input. Think high power DC to DC converter. Considering the number of 1500v suburban systems in Europe, that capability may already be in Siemens systems.

        The bigger problem is finding the cars. TriMet shows a significant surplus on paper, but I think they are doing mid-life overhaul on a significant number of those.

        The only cars that don’t suck that are being retired right now are San Diego high floor cars, and those could never be operated in multiple with the Kinki-Sharyo cars on hand, but they would have to be in order to work.

  17. Shorter headways will keep passengers out of each others’ way on platforms. Which are small for their purpose. Really important for weekday rush hour, when not everybody is going to the special event.

    Airport trains need more luggage capacity. For the price and the traffic jams, I think most passengers would prefer LINK (if the Port of Seattle would tell anybody about them!) to Uber. Have been suggesting folding seats, benches, and hand-holds.. Easy experiment to do, and reverse if it doesn’t work.

    Tunnel buses? Some choices: Get the Tunnel working as designed, skill, training, 180 degree shift of attitude and all. By people on every tool from a mop to the pens of a County Executive, a Mayor, and a Sound Transit CEO.

    Or decide that, as planned from the beginning, the phase of joint operations is over. As I think all three above agencies have already long since decided. King County, when bus drivers started collecting fares. The City of Seattle, with Convention Center kickoff. Sound Transit, when it didn’t immediately start raising Hell about the damage to their own operations.

    So considering the last years-long drain on efficiency and outlook, let’s change “ops” soon as possible. Major positive: strong motivation to get those street lanes reserved and signals pre-empted. By Christmas if we can’t hit Thanksgiving. The sooner we get the change made, the sooner politics and people will adjust.

    However, most likely choice is the one agencies, operators, and passengers are most comfortable with. As long as every passenger vehicle that goes in one end of the Tunnel and comes out the other, no changes are worth the extra sweat they’ll cost. Water conservation, I guess.

    Mark Dublin

  18. Quick edit: Got carried away with architectural metaphor regarding vertical arrangement of floors and offices. Elevators IDS make it easy for other group named come take some lessons.


  19. It may not make a huge difference, but would getting Metro drivers to enter the tunnel in the right order help? I’ve noticed many times that an outbound 550 will pull into Westlake with an outbound 101 or 106 right behind it. The latter have to wait for the 550 to load at the middle bay before they can pull up to the front bay, doubling the platform dwell time for the platoon.

    1. I think that’s what Mark Dublin mentioned about the unused tunnel-signaling feature. Central control can’t communicate with the buses or such, to tell a 550 to wait for a 101.

    2. I’ve never understood why they don’t use the center lane to pass in this situation. Sure, it’s a “three lane road”; drivers need to put on the turn signal for a few seconds and scan the other bays for opposing buses asking for the lane first before moving into it. How hard is that with professional drivers?

    3. David and everybody else, if King County Metro could spare one iota of attention to anything operational that happens between Tunnel portals, join operations could improve exponentially.

      Saving millions in lost operating costs. Judgement elsewhere here still holds. As long as passengers and constituents think present arrangement isn’t worth the effort to fix- much worse problem than money- just pull the buses and let resulting outrage force the agencies to clear the streets for transit.


  20. For “mega events” you really need both frequency and longer trains.

    What I suggest is more frequency to get people to the event, but couple a few two car trains into four car trains to give a capacity boost as the event gets out and the closing crowds start to flood the system.

    Considering the auto traffic these events unleash, are a few more light rail trains on ML King going to be noticed that much? Sort turn some of the trains at Rainier Beach. The trains need to go far enough to connect people to local buses, but as people get off there are fewer passengers.

    I really don’t think a few extra trains an hour on ML King will be that noticeable. In places TriMet runs 2.5 minute headway on the surface. If they try it once and it doesn’t work then so be it. It was a one time event.

    Nice new possibilities open up if it does work though.

  21. Frequency is king. Please don’t add capacity at the expense of frequency.

    I don’t get this obsession with the vehicle lifecycle at the expense of meeting current demand. There is a cost to not serving current demand which needs to be considered in the total return on investment.

    Also, there are so many changes on the horizon in terms of vehicle design/technology/delivery that I’d run the current fleet at its maximum even if it shortens the lifespan.

  22. Remember that Link Light Rail, Sound and Metro Transit made it through the Seahawks Super Bowl Parade and for that event they had 2 days notice and no idea of how many people would be coming to downtown and how many would be riding transit.

    In the case of the two event days in September they know that they are coming with time to plan and they should have an idea of many people will be attending each sports event as they should be able to get information from the Mariners and Huskies of many tickets have been sold before game day. The extra factor on September 30 for the Huskies game is that kickoff is around the same time as the afternoon rush hour but Sound Transit should be able to take a look back at the number of riders from previous Fridays and have a good idea of how many rush hour riders they should have.

    It is going to be busy no question about that but unlike the Seahawks parade they have the time and they can plan for it.

    1. Actually, Metro and ST left tens of thousands of riders at the curb and at the platform on parade day. Every other transit agency had the same problem. The crowd overwhelmed every agency’s capacity.

      Metro could have scavenged some relatively empty cross-town runs to run more buses downtown. But then, the buses that made it downtown had trouble getting back out.

      That phalanx at Airport Station filling the bridge across Pacific Highway watched helplessly as train after train showed up, full of riders who took the train south stayed on board, and nobody else could get on to go north. A chunk of that phalanx had gone there after the extra Sounder train was packed, and left thousands to find another way. Eventually, some empty trains were sent down to Airport Station, but the crowd was still way too large.

      The only things that could have made a difference in that mess were to move the demising wall for one day and let 4-car trains run through the tunnel, and to run Sounder all day. It still would not have been enough IIRC, ST got permission to run two extra Sounder trains in the afternoon to help slowly clear the mega-crowd. Entry to the DSTT stations was controlled, while the phalanx to board Sounder went on for blocks upstairs.

      Though to my knowledge, it all went off safely.

  23. according to the ST SIP, with Angle Lake, with a six-minute headway, they would need 19 trains. the round trip cycle time is about 49+49+8+8=114 and 114/6=19. they have 62 cars and want a gap train and some spares. 2×19=38; 3×19=57; that does not leave enough for the gap trains and spares.

    perhaps the Goldilocks porridge is three-car trains and seven minute headway in regular peak service. both trains and buses would flow better in the DSTT. three car trains at seven minute headway provides more capacity than the other options. the average wait time would increase to 3.5 minutes from three minutes.

    the current mixture of two and three car trains must lead to uneven loading.

    what to do until new LRV arrive?

    1. Thanks eddiew, for pointing out the math. I’ve been saying essentially the same thing for over a year.

      If riders have to wait an average of half a minute longer in the tunnel, but buses and trains (all 3-car) get through the tunnel a couple minutes faster with 7-minute train headway, will passengers like the 7-minute algorithm better?

  24. @DavidSeater:

    “I’ve been commuting between Westlake and Capitol Hill on Link, and while the trip north usually takes 3 minutes every once in awhile we go blazing through the tunnel in 2. I don’t know if it’s coming from the control center or from a particularly lead-footed driver, but it does happen.”

    It’s only 2 minutes according to the posted schedules, so I don’t know why you said “blazing through the tunnel in 2”.

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