Improving SODO Station with Cross Platform Transfers

59 Replies to “Improving SODO Station with Cross Platform Transfers”

1. If the goal here is to check the box and say we have rail from Tacoma to Everett, you really don’t care about quality of transfers. Whether they’re good or not good, the box is still checked. This is the kind of inertia you’re fighting here.

   1. Not Tacoma to Everett. Tacoma to the airport and downtown Seattle. If the spine split were south of downtown you might get Pierce and South King against it too.

2. ‘Maintain regional connectivity’ could also be named ‘maintain dijibell’s 1-seat ride from rainier beach to 145th’ so count me in!

   1. Unfortunately, none of the ST proposals do this, though there are ways it could be done.

   2. I don’t know who dijbell is but there’s more widespread trip patterns that would be affected: Rainier Beach to UW (especially for students), to Roosevelt, to Northgate, to Capitol Hill, and Columbia City to all these.

      1. As a Rainier Valley resident that both rides to UD frequently and will be riding to the east side when that opens up, the more diagrams and plans come out of ST the less and less excited I get about Ballard Link.

      2. Erica, if you want to go to Eastside, you might be better off to take the 7 to Judkins Park to catch EastLink than to transfer downtown. For UD, I wish ST would consider keeping the Ballard line separate with a transfer at Westlake.

3. There is another configuration option that might be an even better compromise — stacked center platforms. One platform for each line, one above the other.

   Such a configuration cuts the vertical transfer penalty in half (you either go up or down to transfer, not up then down), and it totally eliminates the horizontal transfer penalty (once you go up or down you are automatically at the other platform. No more walking).

   Stacked center platforms also have the advantage of serving all transfers at the same time. Both unidirectional or bi-directional transfers are accomplished at the same station and in the exact same manner, whereas side-by-side center platforms can only serve one type of transfers at a time. Any other type of transfer needs to be accomplished by going to the adjacent platform.

   That said, I always thought a future upgrade would be to elevate Link from SoDo Station to just south of Stadium Station. The area is industrial, so an elevated line should be OK, and it would speed up Link substantially while improving safety.

   Other advantages of elevating that stretch are that it improves surface mobility (a train crossing every 2 minutes is a lot for the street grid to handle), and it preserves the E-3 busway (which many of the proposals would remove).

   So, if you do elevate, then side-by-side unidirectional center platforms might be possible again.

   And the “maintain regional connectivity” is the correct option, especially since someday the union time restriction is sure to go away as autonomous LRV’s enter the picture.

   1. > Stacked center platforms also have the advantage of serving all transfers at the same time.

      One of the original alternatives was to build an elevated sodo station, though it did have one problem discussed below.

      > That said, I always thought a future upgrade would be to elevate Link from SoDo Station to just south of Stadium Station. The area is industrial, so an elevated line should be OK, and it would speed up Link substantially while improving safety.

      They are planning on elevating lander st instead. this would grade separate both the old and new sodo station.

      For holgate street there’s been discussions of removing the crossing at the amtrak tracks or possibly adding in an elevated road. Perhaps they could elevated it further and separate the link tracks there as well. Though I’m not sure how it’d interact well with the other north/south streets.

      https://www.seattle.gov/transportation/projects-and-programs/programs/freight-program/s-holgate-st-at-grade-crossing-elimination-study

      1. @WL,

         The grade separation programs in SODO are aimed at separating the street grid from Amtrak and BNSF traffic. There is no plan, at least that I have seen so far, that addresses grade separation for the Link tracks.

         The Lander grade separation project is actually considered to be complete. I drive over it about once a week. Check it out on Google maps.

         Additionally, elevating Link from OMF-C to just north of Holgate might actually be cheaper than elevating the street grid. Detailed analysis required.

      2. @lazarus

         > The Lander grade separation project is actually considered to be complete. I drive over it about once a week. Check it out on Google maps.

         Yes, I know about that. they also plan to grade separate Lander street at the link tracks with another new road bridge. https://westseattlelink.participate.online/sodo-station.html lander street would be elevated over the Line 1 and Line 3 tracks

      3. I stand corrected.

         But that sill leaves Holgate. And I bet elevating Link the whole distance to just north of Holgate might still be cheaper (and more effective).

      4. The soil in SODO is extremely bad, which requires pylon foundations to extend very deep below the ground. This increases elevated rail construction costs substantially in the area.

         Meanwhile, road bridges can use stuff like geofoam to save weight and reduce issues with liquefiable soils. The Lander Street project ended up costing $65M; new bridges over Link lines would probably each cost similar amounts, if not less since they don’t have to climb as high as is needed for freight. There’s no way elevating the rails from south of Lander to north of Holgate would cost less than that.

      5. iirc there was a brief study of elevating both stations. but the larger problem was that link service should be shutdown for maybe like half a year while they build the new elevated one.

      6. @WL,

         Since we are talking clean slate, the proposal would be to have both platforms elevated. This allows the station to be built south of the current station and to the west of the existing tracks. Essentially over the busway, which would need to be closed during construction. But Link would not. Link would function normally until cutover.

         Downside is access to the platform from the ground level would require a vertical elevation change. But this is a relatively lightly used station, and I suspect transfers will end up being at least as important as boardings, if not more important.

         Cutover from old to new could be accomplished relatively quickly with a custom structure essentially sistered up against the current ramp.

         Heading north the elevated structure would be a simple platform 4 tracks wide. Such a structure would require a post and bent type structure using two columns instead of the one so common elsewhere on Link. Such structures increase lateral stability in poor soil conditions, which helps in cost mitigation over the single post design.

   2. There is a different way to operate the trains with stacked platforms.

      Northbound trains could operate at the surface and southbound trains could be overhead. If ST scheduled trains to meet at SODO, crossing Lander could be coordinated cutting the gate closures in half compared to today.

   3. I think it’s better too, because West Seattle Link is better being connected with Ballard and linear induction like Baltimore Purple CAV mixed with a Bombardier ALRT.

      BART tunnel cast stacked on 5th avenue.

      Elevated through Interbay and West Seattle, finished by 2032.

4. What is so difficult to understand about “Use the same platforms!”? Since it is the clear preference of the Blog’s membership that a “Duwamish Bypass” never be built, there will never be more than sixteen trains per hour per direction between SoDo and CIDS, even assuming six-minute headways on the Rainier Valley line. West Seattle will never require more frequent trains than ST’s “policy headways” of ten minutes, or six per hour.

   Sixteen trains per hour is one every three-and-three-quarters minutes. If Holgate is also overpassed, and Lower Royal Brougham Way closed between the Busway and the entrances to the Greyhound Station, sixteen trains per hour can comfortably and safely be accommodated by the existing at-grade trackway.

   This of course leaves open the question how to get the northbound track from West Seattle over to the east side of the existing north-and south-bound tracks to and from the Rainier Valley. There is adequate room to do that by taking the bikeway south of Lander. There is an orange painted building at the rear of Austin Mac which might need to be “trimmed” four or so feet to pass the trackway, but that is the only impediment to use of the bikeway for an at-grade track.

   There would be a trailing-point merge turnout underneath the new Lander Street overpass.

   Southbound construction would be a bit more complicated, because it would be ideal for SoDo Station to become center platform. Doing so would make out-of-direction transfers — trips between the Rainier Valley and points south and West Seattle — as easy as the important in-direction ones enabling trips between West Seattle and SLU/LQA/Ballard and between Rainier Valley and south and UW and north.

   To attain this, the southbound trackway and its platform would be “swapped” by re-constructing the southbound side of the station.

   This would require moving the busway between Forest Street and about halfway to Holgate into the existing northbound freight spur to its west. There are four buildings at the north end of the spur, only one of which still has ANY door opening onto the trackway. That one building has piles of what look like fish totes stacked on the loading platform radiating disuse by railcars, and the rails on the spur are that beautiful rust color that steel rails get when a wheel has not turned on them for four decades.

   Yes, this spur is a “non-trivial expense” to remove, but it’s just not being used, nor will it ever be in the future. The real estate would be better used for improving the Link station.

   The first step would be to construct the Lander Street Overpass, the bus loop to its north between Sixth South and the existing station and a ramp between them. Westbound buses should have a turn pocket with full-time signal pre-emption to access the ramp.

   Next, a new, temporary southbound platform with its south end about thirty yards north of the existing one would be built, and the existing platform then removed.

   The walkway to the existing platform would be moved into the existing northbound busway lane with a Jersey barrier to protect pedestrians and would be extended to the new temporary platform.

   The next step would be to construct the new southbound trackway a few feet west of the existing southbound platform with the track to the north bending toward the existing southbound track between the existing platform and the temporary one. That track would be stubbed just short of the outer track of the existing southbound track.

   To the south of the former platform the trackway would go straight in the former walkway to a point under the Lander Street bridge where a facing-point turnout would be constructed with its diverging tracks similarly stubbed just short of the existing southbound track.

   Once the new trackway is ready to carry trains, a weekend blitz would “cut” the new southbound trackage into the existing southbound revenue track. After that connection is completed and southbound trains are using the new pathway through the old platform’s footprint, the former southbound trackway now being bypassed would be taken up and the new, somewhat wider center platform constructed.

   An open-air mezzanine level above the plarform and the tracks between Lander and the new station would be built to provide access to the center platform without requiring riders to cross the tracks. It would have stairs, escalators and elevators to the center platfirm along its centerline.

   Buses westbound on Lander would not need to enter the bus loop between the Link Station and Sixth South, but eastbounds would. The good news for bus riders headed north from the loop is that the old platform could remain in service with northbound trains opening doors on both sides at SoDo, allowing transfers from buses to northbound trains to be at-grade. If departing westbound buses also stopped on the new bridge, southbound transfers from the train would have only one level change.

   Once the new center platform is completed and in operation the non-diverging branch of the turnout south of the new platform would be extended south to Forest Street in the previous northbound busway lane to become the line to West Seattle.

   This configuration would work at the north end of the shared trackage as well, if the center storage track were closed used for the ramp down to the southbound tube of DSTT2.

   This would be a non-crossing “burtowing” junction. Yes, the northbound track to DSTT1 would probably have to rise a few feet, but there’s room for a “shoo-fly” for another temporary track to the east side while the permanent track is raised.

   Of course, most contributors to the Blog believe that DSTT2 as designed is a colossal waste of money and should be abandoned. So there would be no need for a north end to the shared trackage. It would continue to Northgate or Lynnwood depending whether it’s ever extended south of South Federal Way.

   Look, I get it. You think I’m an old “crank”, but suck it up and LISTEN instead of defending ST’s willingness to blow a couple of billion and kill the busway in the process in order to build a separate trackway directly adjacent to an existing one for six trains per hour.

   That needs to be called the stupidity and folly that it is.

   1. “You think I’m an old “crank”,”

      You kind of are when you refer to things as Skycastle Transit and think ST staff are wrong or stupid for not doing what you believe they should be doing. Honestly, you’re own cynical attitude towards ST blinds you in a way to the good things they are doing. You don’t have to like what they’re doing, but they are doing good in building infrastructure for the long term well being of this region.

      Maybe stop being less cynical and smell the roses more.

      1. They are wasting money at a colossal rate and are planning to do so even faster in ST3. There’s some indications that Mr. Sparrman and Vice-Chair Balducci are having some success reining in the starry illusions, but it’s not a done deal by any means.

         Perhaps Trump’s coming impoundments will get their attention.

      2. “They are wasting money at a colossal rate and are planning to do so even faster in ST3.”
         Again, you are letting your own cynical attitude towards things blind yourself. It’s unhealthy and unhelpful to yourself or others here. You’d benefit from stepping back and look at the bigger picture instead of getting angry at ST everytime they do something you don’t like. Letting perfect be the enemy of good benefits no one.

         Honestly, if you believe you can do can better than them then put your money where your mouth is and go work for them. You clearly believe you know better than the people currently working there, then go work for them instead of complaining here that they’re doing everything wrong because that benefits no one but yourself in believing you know better than people who its their job to plan and design these pieces of infrastructure.

      3. It’s not just me who thinks they consistently do a poor job. Look at the limited access so many of the new stations have. How many people have complained and pointed out how egregiously punitive ST has been by omitting escalators? How about the elevator failures in recently built facilities? Plenty of people have complained about that. Maybe ST needs Schindler’s Lift. The power system in the almost new tunnel north of U-District is already flakey. Lots of flak has gone up over that.
         ST chose fifty-five mile per hour slow-floor [sic] LRV’s with which to build an interurban subway and fewer and fewer people are defending the technology choice.

         Yes, with the exception of skipping the First Hill station, the North Link alignment is great to Northgate. There are good arguments to be made for extending the line farther than there as well because the freeway is a mess most times of most days. However, the freeway hugging through North Seattle and Shoreline means that the system will never perform to its greatest potential, and going north of Lynnwood is wrong, wrong, wrong.

         East Link is in theory a huge winner, because it links two very prosperous and dynamic CBD’s. But the bridge will always be one catastrophe short of permanent closure and then it’s back to the East Side Starter Line.

         They didn’t need to go a yard south of Angle Lake, either, because it would have been easy to include bus-only ramps down to 28th South instead of an elevated trackway above 28th and alongside the new freeway over to I-5.

         They certainly don’t need to go beyond Federal Way. The skinny strip between I-5 and the port will never be developed enough to make the three stations along that stretch contribute anything to ridership. And the damn thing won’t even go into downtown Tacoma. Has anybody working for the “planning consultants” ever taken Transit 101?

         And finally, does anybody believe that “Issaquah Link” is a good solution to any problem except how to get the Eastside Sub-Area up to a proper expenditure level in order to pass ST3?

      4. @ Tom

         Elevators always break down in their first year after installation than they will any other year of their shelf life. That’s just how the technology works. Yes it’s annoying (especially to me ♿), but it’s a flawed criticism.

      5. @Erica J,

         You are absolutely correct. Large systems usually have more problems in thier early years of operation than they do in later years.

         There is an easy way to visualize this using something called “the bathtub curve”. It has been posted on this blog before, but here it is again:

         https://en.m.wikipedia.org/wiki/Bathtub_curve

         Please also note that some people just love to complain.

      6. That “bathtub curve” refers to a specific product or service. Yes, there’s a learning curve as “the bugs” that are exposed by use are discovered.

         However “elevators” or “escalators” as a generic class don’t do that, if they are properly installed. And that is the rub: ST seems only to care that the box got checked, not that the work was world-class, as it should be, given the exorbitant prices ST is paying for the system overall.

         Any given model of one –unless it’s the latest and greatest — has already been through the poor engineering or execution bugs at other installations

         ST cheaps-out on passenger amenities and then spends millions on prettification.

         Look, I like the flashing cards, too, but I’d trade them for more functioning escalators.

      7. @ Tom Terrific,

         “However “elevators” or “escalators” as a generic class don’t do that”

         You are dead wrong about that.

         Elevators and escalators are complex devices that are assembled on site and each installation often varies from the previous one in subtle ways. As such, there are often issues with fasteners, alignments, tolerances, and safety devices that trip off. It’s common to discover such things during the so called “burn in period”.

         And ST isn’t doing this work all by themselves. Most of this work is contracted out to the elevator and escalators are companies themselves. You know, the experts in the field. And, as such, usually comes with various warranties.

         But hey, I’m just glad that ST has improved their design process to provide redundant conveyance paths. That is a good thing to have.

   2. I’m no expert in how rail yards work, but I’m interested to know whether or not OMF tracks can be reconfigured for revenue use. They already seem to have a nice flyover configuration. If so, and if we wanted the 1 Line and 3 Line to share tracks at Sodo, we could just build a track connection somewhere near the south end of the OMF and avoid this complicated sounding construction process near Sodo station altogether. (By the time the 3 Line construction starts, OMF South will be finished to help mitigate impacts, right?)

      I’m skeptical of the benefits of reconfiguring Sodo into a center platform. Years of either single tracking or outright closure in exchange for 3 stations to save 2 minutes going to airport.

      1. They are already planning on building a new sodo station and having a temporary track to detour while building it. It wouldn’t change that much for construction time lines.

         > I’m skeptical of the benefits of reconfiguring Sodo into a center platform. Years of either single tracking or outright closure in exchange for 3 stations to save 2 minutes going to airport.

         It’s not just to the airport but anyone traveling north/south of sodo (heading to uw or lynnwood etc..)

      2. Not years, one weekend to cut in the new trackage and only in the southbound track. There’s a scissors two blocks to the south at the OMF, and the pocket a half mile to the north to handle the cross-overs for single-tracking.

         Railroads add turnouts all the time; it’s how they add capacity. Yes, of course construction would take years for the whole station, and the temporary platform, considerably farther from Lander, would be used for at least six months while the platform is re-configured.

         So far as using the outer loop at Forest Street, yes, that might work, but it would be fairly slow. The curve into the ramp up from the east side of the loop is pretty sharp, about like the curve from Third to Pine. And the diverging turnout from the southbound main to the outer loop is almost certainly 10 mph max.

         But it certainly should be investigated.

         It is foolish to waste all that money on a second adjacent trackway for six trains per hour in each direction.

      3. @WL, Tom’s original comment discusses the case of a 2-track Sodo station, not the ST-proposed 4-track solution. So same direction transfers are seamless already. The only thing a center platform would add is better West Seattle – Tacoma connectivity, which has dubious value for what would be an expensive project.

      4. The only thing a center platform would add is better West Seattle – Tacoma connectivity, which has dubious value for what would be an expensive project.

         Good point. Sharing the tracks provides the most benefit as it would make same direction transfers trivial. If the tracks eventually diverge (which is the plan) then this would be the most common transfer. West Seattle to Ballard or the Seattle Center. Rainier Valley to the UW. Northgate to the airport. All of these transfers would be much easier.

         In contrast a reverse direction trip is probably not going to be common. Nor would it be terrible. You just look both ways and cross the tracks (https://maps.app.goo.gl/kwZoSKPvjhmaZoAx9). They are various places where people have to do this. Of course there should be gates (it is crazy there isn’t) but center platforms are not a requirement.

         To make that happen you would essentially just “stub out” the line after SoDo. The lines would come together for SoDo and then diverge (towards what they hope will be a new tunnel). If we decided *not* to build a second tunnel (as many of us have suggested) then the stub is just a turnback that rarely gets used.

         Sharing the tracks has other advantages even if we continue with the current plan. It means that West Seattle Link is a lot more useful during the period between it and Ballard Link. There wouldn’t be many riders but it is quite reasonable to use the train if you were headed from Alaska Junction to the UW for example. The required transfer at SoDo would be much better. It also means that when the trains aren’t running very often the train from West Seattle *could* keep going north (which means riders at night or maybe even the middle of the day) could avoid a transfer. This means the only time someone would be forced to transfer is when the transfer wait time isn’t that long.

      5. Yes this. I’ve been surprised that the West Seattle tracks don’t simply run through or above the OMF. ST has planned a tail track into the OMF anyway from the WS tracks. Why not just simply tie into the Beacon Hill tracks south of the incline curve? No messy Lander/ SODO station geometry is needed.

         It may be because ST wants to buy more property in SODO for the curves. The more that these projects take shape it appears as a massive real estate purchase and avoidance strategy more than a beneficial project for riders and taxpayers.

   3. Replying to self to give this caveat: The best thing to happen at SoDo is “nothing”. All these efforts to improve the SoDo Transfer between Lines 1 and 3 are moot if WSLE is not built, and I obviously believe that’s the best thing to happen: the ubiquitous “No Build” would carry the day in any rational needs and solutions analysis.

      1. I agree. I would say the second best thing to do is not build a second tunnel. Just mix the West Seattle Line in with the other line before SoDo and have all the trains go to Northgate. Some would go farther — the trains from Tacoma would not.

         Ballard Link would then be a completely independent line, which means it could be automated and run more frequently. It could end at Westlake initially (which means it could be built much sooner) and eventually go to First Hill (providing more coverage). This is better in many ways and it would also provide significant service improvements much sooner. West Seattle would not have to wait until Ballard Link is done (which is probably twenty years away) before there was a train from West Seattle to downtown. Ballard would get their connection to downtown much sooner as well (although the connection to the south end of downtown would require a transfer).

      2. “The best thing to happen at SoDo is “nothing”. All these efforts to improve the SoDo .”

         Consider this:

         ST3 promised 33,000 to 37,000 riders per day in this ballot measure material: divide that by two for boardings so it’s 15,500 to 18,500 weekday.

         https://www.soundtransit.org/sites/default/files/LRT_WestSeattletoDowntownSeattle.pdf

         The recent EIS says it would be 12,900 weekday boardings.

         https://www.soundtransit.org/sites/default/files/documents/03-WSLE-FinalEIS-transportation.pdf

         That’s a significant drop. And it’s a later horizon year.

      3. Ross, if you can get ST to use the outer ring at Forrest Street, then sure, that would be an excellent way to make the diversion southward without revamping SoDo Station and disrupting the busway. I think there’s room to build another track west of the outer loop between the yard throat at Seventh and Forrest and the new access track on Horton. It would trim a few feet off of each parcel fronting on Sixth along there but not much. It could be elevated and perhaps if it were, the supports could fit within ST’s current property.

         Such an elevated track would just merge with the rising exit track from the OMF after it rose to meet the revenue track.

         However, doing this forbids the bike lane solution, because the tracks would have to cross at Horton and the busway, and the northbound track could not descend to pass under the southbound track. The spur that serves Franz would be in the way.

         That means that the Robin Hood’s Barn solution of going south a couple of hundred yards from Horton, east several hundred yards around the south edge of the OMF, north a quarter of a mile and then a couple of hundred yards up the ramp is unavoidable. That is slow trackage though it does seem to have bern designed for the outer loop to be a turnback.

         Of course we can hope the WSLE isn’t built because Trump reneges on the Federal funding and it’s all a moot point. It is well-insulated from the other trackage.

         There is enough room to build an elevated loop for northbound trains outside the at-grade outer loop, though it would require cutting down the trees along Airport Way. It would also0p have to dip down to pass under the Spine Line next to but higher than the track from the outer loop to the northbound Spine track. It would merge with that track’s ramp alongside Forrest Street.

   4. > Since it is the clear preference of the Blog’s membership that a “Duwamish Bypass” never be built, there will never be more than sixteen trains per hour per direction between SoDo and CIDS, even assuming six-minute headways on the Rainier Valley line. West Seattle will never require more frequent trains than ST’s “policy headways” of ten minutes, or six per hour.

      I do not support west seattle reusing the tunnel because it will mean decreasing frequency on the rainier valley segment. sound transit will not be able to justify having the frequency of three trains at current frequency.

      Anyways this discussion is probably for another thread. It’s too much to bring in 2 line transfers, west seattle through running, ballard stubs etc… all into one thread so I’ve focused on the cross platform ones here.

      1. sound transit will not be able to justify having the frequency of three trains at current frequency.

         Why not? Fairly soon Sound Transit plans on running trains to Lynnwood twice as often as they run now. Lynnwood! I get why you would want to double frequency from downtown to the U-District (or even Northgate — the first place you could easily turn around) but Lynnwood is clearly overkill. But they will do it anyway. In fact, as the line gets even longer (and people switch from driving to the Lynnwood Park and Ride and instead use park and ride lots that are further north) the plan is to send both sets of trains all the way to Mariner. Running three trains (instead of two) from Northgate to Downtown is quite reasonable (and much cheaper) in comparison. That means the train from Tacoma turns back at Northgate while one turns back at Mariner and the last one continues to Everett. It would be easier to justify that level of service than what we have planned.

         In any event what Tom is proposing would allow for the second tunnel. We could have five downtown tunnels (all with no additional downtown coverage like the proposed one) and it would still be OK to have the trains from West Seattle and Rainier Valley use the same station. It would certainly be OK given the current frequency. But it would also be OK given any future, realistic frequency. It isn’t like the Ballard Line. From Ballard to Westlake is a fairly urban area and the route is fairly short. If it was automated and independent then running every it every three minutes is realistic. But neither of the two southern lines are like that. The line that goes to Rainier Valley continues all the way to Angle Lake and will soon go all the way to Federal Way. You gain very little by running that train more often. It is also limited because of traffic in Rainier Valley to running every six minutes. West Seattle is more urban (and a short line) but it is part of a branch. Again, I don’t see trains going to the East Side every couple minutes given the length and nature of the route. At best we are looking at six minutes again (just as Tom said). That six minutes is *more* frequent than they run now. Current frequency (7.5 peak, 10 minute midday) would be much easier to justify.

      2. > . Again, I don’t see trains going to the East Side every couple minutes given the length and nature of the route. At best we are looking at six minutes again (just as Tom said). That six minutes is *more* frequent than they run now. Current frequency (7.5 peak, 10 minute midday) would be much easier to justify.

         It is not about peak frequency but about off-peak frequency. sound transit will likely be running 10 minute frequency on each branch for 5 minute shared in the downtown seattle to lynnwood segment. It is likely it’ll drop down to 12 minute frequency later in the evening.

         With 3 branches, the drop to rainier valley frequency will be even more severe.

      3. WL, do you really think that the RV can support more than ten trains per hour with all those traffic signals? Ten (max RV) plus eight (max I-90 bridge) plus six (ST policy headway) is twenty-four trains per hour. That is a train every two and a half minutes.

         I do understand that the RV trains will introduce quite a bit of variance in timekeeping unless Seattle allows the signal timing on Martin Luther King to be affected by trains. That is, if the signal is green but the train is a bit late, hold the signal until the train passes through. If the signal is red and the train gets a little ahead, advance the green.

         The most valuable thing the Seattle could do is to forbid left turns from King to the cross-streets. That simplifies the signal cycle by removing one entire green-yellow series. If that were done the reliability of Line 1 trains would improve so that two and a half minute headways would not be out of the question.

      4. @tom
         The problem is not peak frequency but with off peak frequency

      5. WL, I don’t understand your off-peak concerns, can you elaborate? If headway drops to 12min on each branch, it would mean 3 lines would run 4min headway through the tunnel. What’s the issue?

      6. @Martin

         The problem is that the rainier valley segment (and east link) frequency is lowering from 8 or 10 down to 12 minute frequency.

         Even 4 minute frequency is “too much frequency” or from sound transit’s perspective wasted off peak so they would continually be trying to lower it even further.

      7. Sorry, WL, I can’t see anybody complaining about too much frequency (unless you’re trying to do maintenance). Personally, I would love to see that frequency during off-peak. So much easier to get from CapHill to CID at all times.

      8. The problem is that the rainier valley segment (and east link) frequency is lowering from 8 or 10 down to 12 minute frequency.

         OK, so your argument is that ST would drop the frequency to the South End (and East Side) to 12 minutes because running 3 minutes 20 seconds between downtown and Northgate is a complete waste? Sorry, that seems absurd. If the south end of Link gets a reduction in frequency it will have nothing to do with the most productive section in our system. It will have everything to do with simply going too far. It is quite common for agencies to run trains to the hinterlands promising ten minute all-day frequency only to let it slip to 12, then 15, then 20.

         Again, this agency has no issue with running trains every five minutes (midday!) to Lynnwood. Why would they mind running a few extra trains to Northgate? Hell, it is quite possible that would pay for itself. Going from 5 minutes to 3.3 minutes doesn’t add up to a bunch of new riders but it still adds up to new riders. Given the relatively short distance I don’t see them dropping frequencies for that reason.

         Put it another way: If they want to drop the frequency to the south and east, do you really think that the north end — having half the frequency — is what is stopping them? If so, how do you explain the fact that the trains from the UW to downtown only run every 10 minutes midday (instead of 7.5 minutes like during peak)? If they feel like dropping frequency from the airport or Bellevue to every 15 minutes midday then they will do it — and the folks at the north end will live with service that is actually better than it is now.

      9. > Sorry, WL, I can’t see anybody complaining about too much frequency

         @Martin sound transit isn’t going to run that often off peak.

         @Ross
         > Put it another way: If they want to drop the frequency to the south and east, do you really think that the north end — having half the frequency — is what is stopping them?

         Ross having three branches heavily cuts into the frequency. And usually they’ll want to keep the frequencies same on all the lines. For them to run one more train to rainier they end up having to run trains down all the other branches as well.

         Also I’ve explained all of this before on the other threads. It’d be slightly helpful if I didn’t have to reteach this from the beginning again.

      10. > running 3 minutes 20 seconds between downtown and Northgate is a complete waste

          It’s not 3 minutes, it’s an extra 41 minutes from sodo to lynnwood. Or at least 25 minutes from sodo to northgate.

   5. What is so difficult to understand about “Use the same platforms!”?

      Good point. A center platform station that served both lines solves the problem. It is highly unlikely this would cause any sort of delays. The trains down Rainier Valley will never be that frequent. It is quite likely they will never be as frequent as they once were. The train to West Seattle would certainly not be frequent. It would be a branch of the main line to the UW but because it would be a branch at most it would run as often as East Link which is still not expected to run that often. Even if you eventually need a second tunnel (because of East Link) the branch would happen later.

      1. Al suggested this long time ago. It makes the most sense and would allow WS trains to turn around at SODO (with on platform transfer) or continue to Northgate immediately. It would allow for cross-platform transfer from WS to RV or airport, too. I have no idea why Sound Transit has not considered this or running through the OMF.

   6. What’s wrong with PTC Tacoma-Lynnwood bypass at Algo?

   7. One way to look at this “use the same platform” scenario is simply to encourage ST to not build the SODO station palace with West Seattle Link stub phase but not give up on more platforms eventually. The demand for the stub period will never be over 6 trains an hour even during the peak. The West Seattle trains can use the third track south of Stadium Station to reverse the trains.

      Then encourage ST to rearrange the OMF tracks so that they feed West Seattle tracks directly. Keep in mind that by the time the stub opens that the Federal Way OMF will also be open. So it frees up Central OMF a bit.

      Doing these two things shaves at least a half billion from West Seattle Link project.

      Then the whole station thing can be reevaluated if or when DSTT2 becomes affordable.

      It may be necessary to still build street overcrossings at Lander and Holgate for Link.

      And I think West Seattle residents would prefer this. As it is now, West Seattle residents have to take time to go up and back down again to change trains at SODO. That not only takes time but is lots more physical effort — especially when an escalator or elevator is out of service. They would only have to hop off a train and wait right at the platform for the next one.

      First a train from West Seattle arrives at SODO, unloads and goes north to the current siding to reverse direction. A train from SeaTac headed to Downtown arrives hopefully 2 minutes later and keeps running towards Lynnwood. Once the stub train has been reversed it waits there on the middle track until a southbound train headed to SeaTac goes past it. Then the stub train follows right after that one, stopping at SODO to pick up riders bound for West Seattle.

      One other beautiful outcome: the SODO busway remains untouched for at least another decade.

5. THANK YOU!!!!!

   At least someone besides me sees that the benefit is worthy!

   My next comment is that rail track engineers should figure out cage connections that work best as long as there is a cross platform transfer at SODO. There may have to be a property take at worst case, but it’s a heck of a lot cheaper to build than the “chutes and ladders” transfers that Sat keeps proposing.

   I’m also thinking that the switches into the OMF could be used during construction as needed. I’m not convinced that it would be disruptive.

   Finally, this needs to be discussed NOW before WS Link goes to final design.

   1. Oh… one other comment:

      The scissor tracks to operate trains on the other set of tracks gets much easier to install. That helps when there are disruptions on one of the lines!

   2. Typo: cage = which

   3. I’m too pissed off because of the screwup with my Brother and Community Transit.

      I guess nobody enjoyed 3 Rivers.

6. This change is essential to give any productivity to the west Seattle Link stub.

   The stub is scheduled for 2032 although I don’t see it opening until 2035.

   And funding as well as project cost likely pushes DSTT2 to probably 2045, 2050 or even beyond that.

   So if I’m from West Seattle, I should be advocating for making this design change at SODO! The transfers would not require two elevators, escalators or stairs. It would just be a few seconds to cross the platform.

   I actually think cross platform transfers are such an obviously good idea that most of the public is expecting them. Imagine the shock when someone rides for the first time and realizes how stupid the current design is if it gets built!

7. Cross-platform is good to have, but not something necessary to have.

   Without small headway or good coordination of schedule between two lines, you can easily overflow the platform, which could be dangerous.
   And I don’t think Sound Transit will build island platform very wide or feature platform screen doors like Hong Kong MTR style.

   1. That’s like saying high-quality transit isn’t necessary. There’s no justification for not having cross-platform transfers, or center platforms for turning around. It just wastes passengers’ time, makes them less productive, and is a drag on the city’s economy. It’s the same issue with down escalators: two-way escalators should be a minimum requirement. The point of building a subway is to encourage the most people to use it. Not to make it hard to use so that people grumble or don’t use it. That’s just leaving ridership and benefits to the city off the table.

      Overcrowding should be studied specifically for each station, and a solution generated that preserves center platforms and cross-platform transfers as much as possible. Not to prematurely dismiss them because of theoretical problems that might not occur or might be small. Even if there’s crowding for an hour a day or an hour a month, most of the time there isn’t and the center platforms would still be beneficial because the’d save passengers time and effort.

      Re platform screen doors, that’s ST’s responsibility. If it neglects recent industry standards (like it’s doing with automation and open-gangway trains), the blame falls squarely on ST, and we shouldn’t make it worse by not having good transfers because “ST probably won’t install platform screen doors”.

   2. I think it is far more likely that the currently proposed elevators and escalators get overwhelmed with transfers, than people doing a single platform transfer.

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