The Green Line subway that Sound Transit seems certain to propose next year has one stop between Westlake and International District/Chinatown, on Madison Street. Falling between two existing DSTT stations, it would greatly improve integration of Madison BRT into the rail system.
The Sound Transit concept places the stop at about Madison & 5th Avenue, right in front of the Central Library and a block from the I-5 trench. But what if we could use this opportunity to correct one of the most regrettable outcomes of Sound Transit 1, the deletion of First Hill Station?
Moving a station away from 5th takes the line away from the region’s tallest buildings, but these buildings are well-served by existing Link Stations. Nudging the line up to Madison and 8th Avenue has negligible impact on tunnel length (0.05 0.09 miles according to Oran’s software)*, and places all three hospitals within easy walking distance of Link (see walkshed map below). Reaching Boren would be much harder, adding a quarter mile and in practice forcing transfers for many Green Line riders headed downtown, but locates the station very near the hospitals and credibly serves Seattle University and the entirety of First Hill.
Although the 8th Avenue option isn’t a huge change in linear feet, the surface of 8th Avenue is 65 feet above 5th, and Boren is another 52 feet above that. That implies either an even steeper climb for the trains (before dropping down again to Westlake), a more expensive deep station, or both. And it involves tunneling under I-5 twice.
When I asked ST spokesman Geoff Patrick about these possibilities, he didn’t dismiss them, but I got the impression that the question was definitely outside the box. However, “it would be a board policy decision,” so if local officials understand that is feasible, desired, and very much needed, they can bring it onto the agenda. It’s certainly worth a look from ST planners.
* If tunneling costs $600m/mile, that’d be $30m $54m in additional expenditure on a multibillion dollar project.
So the Westlake platforms are to be under Seventh, not Sixth? That makes the Westlake transfer almost as inconvenient as the IDS foot powered roller coaster.
Grant that it does make underground access to the Convention Center a real possibility and puts the north end of the Green Line Mezzanine closer to the center of the Denny Triangle, both “pluses”, overall this is making system integration worse and worse.
agreed, Westlake Station ought to be closer together if possible. Direct mezzanine connections are a must in either case.
The simplest design is also the most elegant and most efficient. Have the platforms for the Green Line lie under Fifth Avenue centered north-south at Pine with a direct pair of escalators between center platform and the existing Mezzanine “bulges” from near the ends of the new Green Line platforms. Then, include a pair of direct escalators to each of the existing side-platforms for the Red and Blue Lines closer to the middle of the Green Line center platform. There would be no additional Mezzanine for the Green Line. The Westlake Mezzanine is already huge.
That way there are four ways between the Mezzanine and the Green Line platform: two direct and one via each Red/Blue Line platform. And transfers between the two tunnels requires just a walk to the center of the Red/Blue Line platform or a bit north or south of the center of the Green Line platform followed by a short escalator ride.
The design above requires a minimum of a block and a half walk between the ends of the Red/Blue platform and the Green Line Mezzanine, plus an average of half the length of the Red/Blue platform.
That’s quite a hike two times a day, especially if you force everyone on the Green Line headed for the financial core to change to the Red/Blue by moving the Madison Station uphill. Grant that some will get off at Madison and walk downhill in the morning on a nice day, they sure a Hades won’t walk UP in the afternoon.
I agree with this, except that I’d argue that the Green line platforms whould be as far to the northwest as possible while allowing the escalator from the NB Red/Blue line platform to land on the Green line center platform.
There should be four pairs(up/down sets) of escalators to the Green line platform. Two pairs between the Red/Blue line side platforms, on pair from the Westlake north mezzanine, and one from a new mezzanine that has exits in the vicinity of Olive or Stewart. If that part of the station is cut & cover, an upper level pedstrian passageway between the Westlake station mezzanine and the new one should be built.
Good ideas, aw.
aw,
I like your idea of a new “north mezzanine”. It gives underground access to the bottom “point” of the Denny Triangle.
I agree Westlake needs to be closer together, especially if we’re going to force a lot of transfers by putting the Green Line Madison station in First Hill.
+1
This design would force a lot more transfers at Westlake and IDS, so for it to work, those transfers had better be good. Under the original plan, if you’re in the core of downtown, in the walkshed of the fifth and madison station, you’ll walk to that station to get to locations on the green line, even if a blue line station is closer. But under this map, you’ll have to transfer, so that transfer had better be good. It’s OK, I guess, to require somebody from 4th and Marion to transfer to get to SLU – but only if that transfer is excellent. A two block walk is not an excellent transfer.
A Seventh Avenue station raises an obvious question: Why are we selling the Convention Place property? Aren’t we going to need it for construction staging and maybe more?
Boren and Madison! Let’s make it happen!
What a grand idea to fix the 1st Hill mistake. Bring it.
Can we return the streetcar and get a refund?
It’s still under warranty, or have they used all the miles doing testing? [snark]
The FHSC delays, in this context, are unfortunate. If the consensus is right that it’s an unsuccessful replacement for actual Link service, it would be nice for that to be clear before Sound Transit has to make important routing decisions.
On the other hand, it’s not clear to me that they would have to hash this out before going to the ballot.
I don’t understand why everyone treats it as recieved wisdom that losing a First Hill station was some grand mistake. I wasn’t in this area during Sound Move, but how would it have even been geometrically possible to have a First Hill station on the current line? First Hill is directly northwest of Downtown. Would it have skipped University Street station and West Lake, or would it have done a U-turn after Westlake only to do another U-turn up to Capitol Hill?
University station would not have been skipped. The plan was always to extend from Westlake station.
The turn would have been sharper than it is now, of course.
D, Original First Hill routing would have had present northbound LINK line swing southeast after leaving Westlake, station near Swedish Hospital, and then northeast under Broadway to Capitol Hill station.
Serving an extremely important area. However, engineers decided that the soils in the area either would not hold transit, or would have made the proposed station too expensive to build.
Some say that the move was political, to assure Federal money. Considering the importance of the stop, I’m skeptical that the station would have been lost for that reason.
Or that the Federal Government would have been happy with that much lost value to the line. For eliminating a critical station which had been promised as part of the project.
I do know that any work underground, tube, station, or foundation, is extremely site-specific.
Quality of dirt. Rocks-including the size of a building. Water- like the creek our northbound boring machine unexpectedly encountered at Century Square.
Better to cancel a dig where you know about these things in advance than to have your machinery find them for you.
As for the First Hill Streetcar- let’s consider it a small first installment on the promised station- and alter Broadway as is necessary.
And start finding examples of actual machinery able to carry rail cars larger than streetcars down a steep grade.
Such things existed in Pittsburgh back in mining days. Also in the Skagit Valley when the dam was built at Concrete.
Expense would roughly level the balance sheet on the loss of First Hill Station.
Mark Dublin
I think the mistake was not losing the First Hill station, but was instead losing the opportunity to have two stations on Capitol Hill/First Hill.
Had we had two stations — especially at Pine/Broadway and at 23rd/Madison — many more of the neighborhood’s connectivity issues could have been solved.
Thanks for the information. I guess I was imagining a station around Boren and Columbia, or something like that. I can see how a bit sharper turn could have gotten you to a station near Swedish.
Good point, Al. It was one thing to abandon First Hill, but it was another thing to not find a replacement. 23rd and Madison would have a lot fewer people walking to it, but it would have made things much better for buses (including the upcoming Madison BRT).
You must mean First Hill is east and slightly south of downtown,
What I like about Boren and Madison (or even 8th and Madison) is that it may serve to connect downtown across I-5 again. I-5 broke off what should have been a natural piece of downtown, and buildings on the east side are generally much shorter. Make it an easy subway connection, upzone to the sky, and we should be able to build up the hill.
FWIW, I would be thrilled with either outcome, but I would probably prefer 8th/Madison as mitigating some of the drawbacks of going all the way up the hill.
Thanks for the great idea. I really like the 8th and Madison Station as well. If you look at the walkshed of the streetcar and the Blue Line, 8th and Madison fills the gap perfectly. I also like the fact that Madison and 8th serves both sides of the freeway helping to knit the neighborhoods together. Not to mention the proposal that has floated around to make 8th a parklike pedestrian oriented street. Boren will unfortunately continue to be a stroad for the forseeable future.
And if we ever lid the trench, the walking experience will be contiguous as well!
Ben, not to over-drop Jim Ellis’s name, but he’d planned for the entire length of I-5 through Downtown to be lidded.
But through signature Seattle cheapout, the present park south of the Convention Center was all we got.
No reason problem can’t be fixed. I just hope the Chinese don’t end up paying for it and getting naming rights!
Mark
Gentlemen, when you’re Dreaming of a Lid Christmas, remember that south of Marion most of I-5 is no longer in the trench; the main lanes are actually elevated. They transition between Madison and Marion, aided by the downgrade toward the Industrial District.
Martin: Math Check. Maps show .26 mi further from a straight bore, so $156m more, not $30, but add more for complex TBM curves and tunnel liner segments, and more for a deep station, so maybe a $200m more as a guess. Oh, that’s the streetcar cost, current $$.
And who knows how much for two I-5 undercrossings?
This’s my main problem with this proposal – it sounds great, and goodness knows I’d use it myself a lot, but how expensive will it be? And what else could we get for that money?
That’s for the Boren route. Martin’s math is for the 8th Ave route.
As Mark pointed out, it would require a fairly deep tunnel. Politically, does SDOT and ST ever want the Seattle Times/Dori Monson’s of the world railing (pun intended) against another “deep bore tunnel”?
ST successfully completed a deep bore tunnel ahead of schedule and under budget; it’s called U Link. And it’s boring more right now in N Seattle without serious issues so far, unlike Bertha.
No arguments here, but Seattle Times Editorial board and its fellow dead enders will say, “the state (even if they are different entites) is one for two– can we risk our precious tax dollars on the government getting it right? This is why I ask STB to get to interview the Kublys of the world, to see if they hint at political calculations being made, etc.
What’s the timeline for a decision to be made on this? If it’s several years out, the ST/Dori Monson types are going to be even less relevant than today.
The Move Seattle vote shows just how irrelevant ST ed board is in influencing transportation decisions at this point.
MDNative,
The biggest risk to me is how deep the station will have to be. Boren would be DEEPER than the Adams-Morgan station on the Red Line and Eighth Avenue about the same. Those are suburban stations, not CBD core. You need a LOT of very long elevators to make it work.
And as I said above, the forced transfer at Westlake just got a lot worse by moving the line one block east.
I think Anandakos makes a very good point. It isn’t the cost per say (although it might be big) but the prospect of a very deep hole below the surface. Beacon Hill is like that, and has an elevator. I have no idea how well that works, how much it costs, or if it makes sense here.
If escalators are used, they will have to zig-zag back and forth. That got me thinking. This may be a crazy idea (and expensive) but what if the station itself was closer to downtown, but the pedestrian tunnel (the escalators to the surface) were not right above, but a few blocks up the street. So put the station at 8th (with one entrance there) but also put an entrance all the way over at Boren. I realize that adds a lot of money to the cost (because you have to drill over, not just down) but the tunnel would be relatively narrow (enough room for two escalators). Given the high value, the cost relative to the overall project doesn’t seem crazy. I don’t know if something like that could be done if the station was kept at Fifth, but as someone who has gone to a few of the stations, it always seems a waste to have to walk right on top of the station, then go back and forth to get to the platform.
I would agree, RossB. There is a culture in station planning in Seattle that expanded pedestrian access (especially down escalators) is an extra budget item and not part of the overall station design requirement. It would likely be cheaper to build an underground tunnel for pedestrians all the way from Boren to the Green Line station (regardless of where it is) than to bore train tunnels and deeper stations up First Hill.
In all honesty I think Al has the right idea: build a two escalator underground trench from a Fifth Avenue Station Mezzanine (it’s going to be deep enough that with a little bit of horizontal to clear the Reversible Lanes Cherry Ramp) up to Eighth or Ninth. The escalators at Adams-Morgan aren’t much shorter than those would be.
That saves the uncertainty of the northern I-5 underpass. I-5 is probably high enough to underrun it at Yesler or so with no effect whatsoever starting with a negative railhead at IDS, but the cut is pretty deep around Union or Pike where it would underpass to the north,
Thank you Al!
Al, ‘Dakos: I like the idea of expanding access to the stations via underground mechanically assisted entrances. It seems to be a promising way of increasing the walk shed of the 5th and Madison station. I agree that tunneling escalators (with one I-5 crossing) would be significantly cheaper than tunneling a train (with two I-5 crossings). Just for fun I ran some math on escalator speed.
Google maps states between 5th and Boren along Madison that the distance is 0.4 miles (2112 feet) with an elevation change of 141 feet. Google maps also said it should take about 10 minutes to walk up that hill. The rate of 10 minutes up 0.4 miles equates to 2.4 MPH. Per Wikipedia, the longest continuous escalator in the US is at the Wheaton station near DC and has a rate of 90 ft/min (~1.02 MPH). If one were to simply stand on this proposed escalator from bottom to top, it would take about 23 minutes (0.4 miles/1.02 MPH x 60min/hr). If one were to walk on the escalator, the resultant velocity would be 3.42 MPH and take 7 minutes bottom to top (0.4miles/3.42MPH x 60).
These are disappointing numbers. So in the end, walking saves 3 minutes and some energy. Waiting for a bus and taking it between the 5th and Boren will be less than 20 minutes (hopefully….), better than just standing on the escalator. This idea probably wouldn’t make the cut when you consider the costs.
However, perhaps instead of escalators, an underground funicular on par with the Penang Hill Railway could be explored. Would love to see this idea studied here along with the LQA station to UQA as well as Fremont to 46th & Aurora.
Istanbul also has and underground funicular that seems to work pretty well.
https://seattletransitblog.wpcomstaging.com/2015/04/06/little-remarked-funiculars-of-puget-sound/
Risking a repetitive comment, I’d note that a three station underground funicular under Jefferson Street from Pioneer Square Station mezzanine to County buildings to Harborview/ Yesler Terrace area would be extremely productive as well. (3rd to 5th/6th to 8th/9th).
Either Jefferson or James, yes, absolutely. The 3/4 around there are packed and crawling.
(And, would an elevated gondola be simpler?)
Yes, William it would be. Some sort of Harborview Connector study would be needed to develop the best approach. I like Jefferson because it would have few traffic issues – so any strategy (underground with tunnel portals or aerial support beams or even surface escalators and stairs) could more easily fit.
What does SDOT think of this idea? Has anyone at STB asked?
Getting people to where they work is important to SDOT and ST (Hence, no real emphasis from them on Ballard to UW; SDOT pushing the SLU station over Belltown) .
While the idea of covering the hospitals is a worthy idea, 5th and Madison is where there are plenty of downtown businesses, office buildings, etc. Can you convince the powers that be that this area is more important (or that the transfer at Westlake to University station would provide enough coverage, etc)
The Hospitals are huge regional employment centers. I work with kids, and I’m amazed how often I find out their parents work on Cherry Hill. These are the median-income or below professional folks who are getting squeezed by the cost of driving downtown but need a reliable way to get to work that feels dignified. Extension of light rail to serve their needs would marginally take a lot more cars off the road than more stops to serve CBD businessmen.
CBD folks have more power (similarly , see also, choosing SLU over Belltown) And while I don’t like it that power talks, it is a reality (just look at light rail to West Seattle). SDOT might also say, “the hospitals are an easy connection from Madison BRT”
Not arguing over the usefulness of serving more people (Ballard to UW over West Seattle light rail anyone?), but political realities have been a major force in SDOT’s plans for ST3.
Ian, thanks for recalling elements deserving more consideration than Dori Monson’s opinion about anything.
Though Luke Burbank is probably worse. Dave Ross finked out by turning over his airtime, though would doubtless come in on our side to make up for it.
Donald Trump is an unknown- except probably to his creditors. But his real value would be same as to Republicans now.
Every rabies-drooling remark would soak up a hundred percent of the media for months. Removing threat of solid criticism or questioning, let alone the kind from the Seattle Times or SDOT.
Honest cost-assessment depends on an accurate reading of the balance sheet. No matter how high the cost, if the value outweighs it, the budget is out of balance.
Mark
Martin, if you were the one who thought of the Boren Avenue idea, much credit to you. And not only for your thought about finally giving the Swedish Hospital area the station it deserves.
Grades and depth have a lot to do with each other. The deeper the bore, the more level the line can be. Depending on soils, rocks, and water, a bored tunnel works just opposite to an airplane.
In flying, the higher the altitude, the safer the flight. Same with mining and depth, in the other direction.
Main consideration here is that a in a CBD as crowded as Seattle’s, it’s worth a lot to get out from under wires, pipes, basements, and foundations More than balancing the extra expense for elevators and escalators.
Any Green Line alignment is going to have to be deep. The nearer the surface, the least room for it. Same in spades for getting under I-5.
I’ve got serious questions about the proposed busway on Madison. I honestly don’t think that by the tape measure there’s room for it, and the blocks are very short.
But for serving a deserving neighborhood, if the ground will take the Green Line- do it.
Mark Dublin
Several people independently thought of it (Martin may be one of those people).
For this post, Martin requested a map of 8th/Madison and I added Boren/Madison as a bonus.
One problem sort of solved:
1) The track geometry isn’t as constrained as the original FHS. No concerns of driving an adjacent station (CHS) even deeper.
A new idea:
1) For the 8th & Madison Station (I like this idea), what about a westward pedestrian concourse under I-5 to serve the tall buildings west of I-5? I’m thinking of something like University Street Tunnel entrance off 2nd & University, which is a near-level walk from the street to the mezz level with the hill doing all the grade change. It could be a small, level tunnel intersecting with the existing ground some distance west.
Two issues that still exist with such a station (but, we have more flexibility than the original FHS):
1) As already mentioned, depth. The original First Hill Station was to be the deepest transit station in North America and 3rd (?) deepest in the world. To get under Westlake Station and the tunnels 20-30 feet below the Express Lanes could push FHS down again.
Some napkin calcs: Westlake is at about 120′ above sea level (~70′ at ex track level) and Boren & Madison is about 340′ at the surface. New tracks would need to be about 50′ below Westlake to accommodate the DSTT2, so about 20′. In the 2000′ between the two points (taking off 500′ for ST design reasons, such as station tangency and vertical curve transitions), with a 5% track grade, the station is still about 220′ below the surface. 8th & Madison would put this station in Beacon Hill territory at ~180′.
2) Station type. Due to it’s depth, these station concepts are nearly guaranteed to be mined stations like Beacon Hill and served by high-speed elevators.
Additionally, be careful giving a cost for these modifications. Changing the station type from a cut-and-cover to a deep mined station changes cost and risk beyond a $30M bit of tunnel. While Beacon Hill was much easier to phase and construct since it’s not in the middle of the city, the soils were pretty darn good, and staging could be done in 3 very close places; FHS will be a bigger challenge. Think SAS or 7 Subway Extension stations with confined surface space and little/no staging up or down the tunnels.
No matter the locations, it’s going to be mined, no? You have to go under Westlake station. Also, there’s some fixed cost in buying the boring machine and getting it in and out. I can’t believe they’d bore under westlake then dig an extraction pit to pull it out and then switch to cut and cover…
Chris, where mining under Third ended at the west end of the cut-and-cover for Westlake Station, the machinery was extracted through the front of the machine, and the casing “shot-creted”, meaning sprayed with cement, into the tunnel wall. Pretty much standard
Which will probably happen with Bertha at the end of its bore- wherever that is. Reason they dug it out and put it back was that decision-makers thought it was worth the risk to let it continue digging until it encounters a sunken freighter.
Where it could be welded to the hull and the south end linked to Pioneer Square for a historically correct Seattle Underground. And -Water.
Boring and cut-and-cover? You can bore as long as you’ve got at least as much earth above the tube as the diameter of the bore.
Any shallower and you’ll have a cave-in, mandating cut-and-cover. Which still allows street traffic during tunnel work.
Recalling DSTT construction, serious mitigating factor was that since more than one office skyscraper was simultaneously being built, Downtown was already disrupted beyond normality.
Something to think about re: any CBD alignment. No matter how ugly, everything on Fifth is likely to stay.
Mark
You’re correct. Even on Fifth Avenue the Madison Station would have to be mined. It’s going to be quite deep itself because Fifth and Madison is a lot higher than Third and University and it’s closer to IDS where the Green Tracks are to be lower than the Red/Blue.
All in all to have decent grades even for Fifth Avenue will require a pretty darn deep station at Madison.
Historically mined stations cost more than cut-and-cover, *but that is not true any more*.
It seems that there are huge costs to cut-and-cover in the form of utility relocation. So mine the station, and you just need to find room for an elevator shaft, an escape stairway shaft, and a utility (electrical) shaft.
So go ahead, put it on 8th & Madison. It’ll be just as easy as 5th & Madison. If the property acquisition can be handled, it can also allow for gentler curves and faster speeds. Put Westlake station *diagonally* between 6th and 7th and relax the curves even more. Direct access to a “northern mezzanine” for Westlake.
Don’t forget Vertical Shaft Machines are an option these days for elevators. For the station itself maybe a large diameter* TBM would make sense, which would contain both direction of tracks and room for a station.
* note: “large diameter” = 38.4 feet, compared to Bertha’s 57 feet or the hand-dug Great Northern Tunnel that is 28’x30′
What about bored escalators… they did it in Prague. Really long, fast escalators. Nice system.
I’d prefer the escalators to elevators. I dont think the Beacon Hill example is one that should be repeated. The elevators are slow and never at the platfor level when the train arrives.
Why would you bore 38 feet all the way to accommodate one station? That’s an enormous amount of soil to remove and dispose of just to make an echo chamber for 95% of the new tunnel. Not practical at all.
The station will have to be mined even if it’s on Fifth Avenue.
Escalators certainly are preferable for handling huge number of passengers if they can be done. However, elevators don’t necessarily have to be slow. The Washington Park MAX station is about 27 floors below the surface and the elevator makes the trip in about 20 seconds. It doesn’t seem like your going that fast until you feel the “I’m going to throw you into the ceiling” sensation at the top.
If it must be Eighth rather than Fifth then Mike’s idea of a Mezzanine to say Fifth Avenue Pedestrian tunnel is a good one. It could have escalators connecting to Sixth Avenue but can’t end there because of the necessary depth to underrun the Reversible Lanes Cherry Ramp.
That would certainly mitigate the disaster to the financial district.
But as I mentioned above, I LOVE Al’s idea: make the tunnel go the other way. That way the biggest trip generators are given direct service and the lesser generators are subsidiary.
Unless there is an easy and direct transfer at Westlake, the 8th or Boren stops should be considered DOA as the Green Line would completely miss the CBD.
The distance from Westlake to ID is about 1.2 miles. The 8th and Boren stops are opposite of I-5, so can be a pain to get down to the CBD. This leaves a gaping hole of walk-ability from the Green Line to the CBD.
Of course, an easy and direct transfer at Westlake would make this all moot.
https://seattletransitblog.wpcomstaging.com/2015/12/12/the-green-line-downtown-seattle-transfers/
A transfer is a given. That is why there is only one station between there (and why Madison was chosen as the station). Otherwise you would just mimic the other tunnel and have all the same stations (they got it right back in the day, and nothing has changed dramatically since then).
No, it isn’t Ross. EVEN THOUGH Martin made his mea culpa about moving the station to Seventh, even Sixth as designed by ST is a complex and time consuming transfer. It will require changing levels and walking a minimum of a half block plus however far from the escalators a rider deboards the Green Line and on average about one car of the Red/Blue train to which the transfer is directed.
However, Mike’s idea of the Mezzanine to Fifth or Sixth Avenue pedestrian tunnel might be a saving grace, though I still think that it’s more important both politically and operationally to put the station IN the CBD so I’d prefer Al’s solution.
But Mike’s idea helps a great deal.
I think this is a good idea for all the reasons mentioned. In addition, and I mentioned this in an earlier thread, while the I-5 and elevation change increase the expense of the going east, by some, (a lot?) it also dramatically increases the utility of the station. Climbing hills is rough, (especially for a lot of people heading to the hospitals) crossing the I-5 trench on foot is unpleasant and for existing buses and cars the bridges congested. This is why adding capacity across the trench and up the grade (via elevators) is so useful.
I don’t disagree– but for the points RapidRider and I made earlier, how does one counter the SDOT/ST pushback of serving the central business district and Madison BRT (they can take transfer to the bus to get to the hospitals)?
If the “md” stands for “Maryland”, next time home check out the DC subway through Rock Creek Park, and especially Dupont Circle Station.
Green Line is LINK-I’m right, aren’t I, Martin- which is probably better than one with any other transit agency in control of it.
Representatives of which, unfortunately, still sit on the Sound Transit Board.
But the history of every tunnel project in the world shows that if SDOT will stop you, you haven’t got a chance against dirt, let alone a rock.
Even if md stands for doctor, above still holds.
Mark
Yup, MD stands for Maryland. Of course, Metro goes under (and over) the Potomac River. We still have not gone over or under the ship canal. Federal dollars helps dig those deep tunnels. On the flip side, escalator repair has been a joke on Metro.
BTW, depending on who you ask, the Georgetown area of DC does not have a subway station because: a) wealthy white residents were too scared of African-Americans coming to Georgetown; b) rocky soil made it near impossible to dig; or c) a combo of a and b.
U Link bored under the Montlake Cut, which is part of the Ship Canal.
Point taken, Oran. But I was referring to the ship canal that the Ballard bridge covers (since almost every Ballard option is 15th and Market)
I like the idea of giving the second a First Hill station, rather than simply paralleling the existing line, but I do wonder about its technical feasibility. The First Hill Station was rejected earlier on technical grounds, and, as far as I know, nothing about the soil under the ground in First Hill has changed since then.
Would the proposed Green Line route be less risky than the original plan, by pointing in a different direction? Or has tunnel boring technology improved to the point where what would have been a risky plan 10 years ago is now considered a routine plan today?
It wouldn’t be in the same location as the previously-studied station, as well as not going in the same direction. The previous First Hill Station was very restricted in its location by the tunnel coming from Convention Center. This tunnel would be much less restricted in station location.
For Geotechnical stuff, a block can make a world of difference.
A station at 8th would be too deep. The line needs to go under the I-5 trench relatively close to the station location. This is particularly problematic to the north where i-5 itself is descending rapidly.
So two close coupled under crossings of I-5? A relatively deep station compared to normal cut-and-cover? Na, aint going to happen.
ST will stick to 5th Ave, and they should.
Yet another line/station that would serve Seattle better that Lazarus doesn’t like.
Detecting a pattern here…
maybe the pattern can be summed up in one word, “reality”.
@lazarus, the one word I’m thinking of is more “politics.”
(Though in this case, you might be right. The more I find out about the I-5 undercrossing, the more prohibitively expensive it seems.)
A First Hill station would serve Seattle better than a Financial District station? Which one has more jobs?
lazarus makes a good point about reality as well.
A First Hill station would serve Seattle better than a Financial District station? Which one has more jobs?
Which one currently has more stations already?
If Sound Transit doesn’t at least look at this option, they’re cutting off one of the most transit-friendly neighborhoods in the state out of sheer inertia and laziness. Is that the “reality” you’re referring to?
No one is saying that this should be built before a study, only that they study it. If it turns out that it is really expensive, then folks can weigh the advantages and disadvantages.
So what is involved in an undercrossing of I-5? I remember hearing that the undercrossing on the existing U-Link line was particularly hard, but I don’t remember why. Is it just because the freeway is somewhat in a trench? Or is it because it’s old and fragile? Or is there something peculiar about freeway design?
Also, Lazarus’s comment about I-5 descending rapidly to the north made me note that the north crossings for both the Boren and 8th alternatives would cross the freeway right under Freeway Park. Would that lead to any particular problems?
The challenge was boring through the foundations supporting the I-5 retaining walls and 15 feet under the bottom of I-5 without causing the freeway to settle too much.
http://acec-wa.org/2014/01/national-gold-award-for-hntbs-university-link-tunnels-under-i-5/
Does this mean that the tunnels follows a path between the columns that support the freeway? Is that possible at the angle that this line would cross the freeway, and if not, how much deeper would we have to go to avoid structural issues?
Sound Transit did work prior to the tunnel boring that removed the foundations for the I-5 retaining walls where the TBM went through and shifted the loads to reinforced foundations on either side. The NB I-5 Olive Way offramp and Pike St reversible ramp were both closed for about a year each to facilitate this. This was complicated by the soils there being fairly unstable.
Basically the tunnel was too close to the surface of I-5. If you run it significantly deeper, you avoid the problem.
URBAN MYTH?
Does anyone know if in fact, the UP started digging a tunnel under 5th Ave @ S.Jackson,about the same time the BN (current owners names) finished their own tunnel to Interbay? I recall Warren Wing saying that (rail historian), but always wondered if true. How far did they make it before giving up, and why didn’t they finish, if true?
could we find a load of suprises when digging under 5th?
Charles, good reference is “The Chunnel”, by Drew Featherston. Inability to see through ground only first difficulty. First question before they started boring was: “Where’s France?”
In New York City, subway-digging crews found, intact, an entire miniature subway powered by a huge fan, built by Alfred Ely Beach in 1869.
Part of surprise was that Beach lied about the thing to avoid having to pay off politician Boss Tweed- in those days almost as big a budget item as consultants.
Also, by the results a lot more worth his wages than the ones who told KC Metro that fareboxes work just fine in the DSTT.
https://en.wikipedia.org/wiki/Beach_Pneumatic_Transit
DSTT Chief Engineer’s anthropological instructions to boring crews re schedule : “You don’t find ONE BONE!”
STB could have “office pool” as to what we’ll find. Including what former Seattleites, with what cutlery emerging from their rib-cage?
But half project fund’s award to someone who finds, under Jackson and Broadway, an intact and operating streetcar line with correct number of overhead wires.
Or even better, the subway tunnel between Seattle and Kirkland from the days of Frederick Law Olmstead that the highway lobby literally covered up.
Biggest surprise will be not to find any. Until we have to dig our machine out from under Columbia Center.
Mark
They attempted to dig one under Tacoma that didn’t work out but I’d not hard about downtown Seattle.
Sorry, Glenn. Should have said “that the highway lobby would have covered up if, unlike railroads, highways even had a lobby in 1912.”
This was the year that Seattle voters turned down a plan by an urban planner named Virgil Bogue, that really did include a rapid transit system that included a subway to Kirkland.
Like all the electric transit cars of the day, the equipment would have looked like the Benson streetcars on steroids.
The Olmsted brothers- Frederick had already died- had already created the plan that included Volunteer Park.
And also a system of parkways through the city specifically designed for pleasure driving. The restoration of which concept being my main motive for supporting public transit.
Unfortunately, whatever the automobile interests conspired to do, they had millions of willing accomplices whom World War II and the Depression had left weary of streetcars- and Density.
The fan-driven Beach subway in New York wasn’t entirely secret in its day. But I think he convinced Boss Tweed that it was merely a carnival ride.
No jokes about the Benson line! When we build its successor, Spec One will be that nobody will be able to think that! Too bad the giant fan idea will only help the Green Line where it’s underground.
Mark
I grew up in the Seattle area and my Dad and I used to go to Mariners games with some frequency. We always parked up the hill from Union Station.
Union Station was closed by that point, but the right-of-way was still there and I don’t remember anything that looked like the start of a tunnel. Tracks extended north from the station under Jackson and ended in a dirt hill as I recall. I think that the building at the northwest corner of 5th and Jackson was built where the right-of-way used to be.
Thanks Andy – I think that puts it to rest.
I did find the tunnel portal from the old Interurban line heading up the hill south of Pacific/Algona on its merry journey to Tacoma.
This is really intriguing, and I’m going to have to sit with it for a while to figure out if I think the tradeoff is worth it.
But I think the cost is pretty high.
There’s the actual cost: crossing under I-5 twice, an incredibly deep station on first hill, crossing the street grid on a diagonal near westlake, where I’ll bet you there are some pretty deep underground parking garages. The risk goes up a lot, and as we’ve seen with Bertha, being ambitious is sometimes a whole lot more expensive than you think it is.
Then there’s costs to the quality of the system: forces transfers for a lot of downtown riders while reducing the quality of those transfers, long trip to the surface from the deep station, added curves slow the train (in addition to distance), and system legibility drops substantially. The map starts to look pretty tortuous and unplanned here.
Adding first hill would be huge. It’s exciting to see a somewhat-plausible to fixing this omission. But I’m not convinced, yet.
EHS, considering civil engineering history, I doubt anybody underestimates the cost of ambition. Unlike recent wars. Or worst of all, present cost and utility of a college education.
For underground transfers, though, places with older subways have often come to include popular underground commercial streets between transit corridors and platforms.
Often of size and scale of Alderwood Mall. Which unfortunately everything else on earth is turning into, starting with Las Vegas. But no worse than any modern airport.
As with the whole Seattle CBD, space available might seriously limit underground malls- except there is a long-existing shopping tunnel under Fifth Avenue between Rainier Tower and, I think, Sixth Avenue.
As with Westlake Station and the whole DSTT, though, skilled engineers and architects can do a lot of urban dental work. Where, unfortunately, you need Gandolf and some dwarfs to find your way.
Mark
I think the issue was the soil issues not the depth, right? That’d be interesting if they included a first hill stop, but like others mentioned, the transfers at IDS and west lake need to be quick and easy.
Also, any hope of an easier connection between king street station and IDS?
Going deeper would actually help with the soil issues, most likely.
As a resident of First Hill (and Transportation Committee Chair of FHIA) I would have to say that we would LOVE to have a station at either 8th/Madison or Boren/Madison. Both locations would nicely mesh with the Madison BRT project and both locations will soon be completely redeveloped.
Putting the station under Boren would bring it closer to Swedish and Virginia Mason hospitals as well as puts it in the middle of the neighborhood (and the top of the hill) … but 8th avenue would probably work out just fine … especially with BRT at the surface.
As for tunneling … First Hill is zoned for 300ft buildings … most of those will have at least 3-5 underground levels as well. If those can be built I cannot see why a subway tunnel could not. As for depth … Link already handles pretty steep grades over 5% in some cases … this means that the tunnels can climb and descend to the station box just like they do on Beacon Hill (which works as a station quite well).
Crossing I5 shouldn’t be an issue … provided the tunnels descend far enough below. The current line’s under crossing was challenging because it passed mere feet below I5 …which of course makes the surface more prone to problems. A deeper tunnel, however, shouldn’t have these issues.
Regardless, once the line has left the station box it does not need to descend to below-westlake levels in a straight path nor does it need to follow the street grid.
However … it does need to have great transfers with the existing line at Westlake … which means the new platforms should be perpendicular (or close) and underneath some part of the Westlake Station … NYC has some insanely long underground passageways between station platforms and I think that should be avoided (especially since we do not allow vending/stores on mezzanines …
Personally I think the First Hill options should be studied. First Hill is one of, if not the densest neighborhood in Seattle with 26,845 people / sq mi vs Seattle in general at 7,779/ sq mi … and employs about 50,000 workers. Add to this patients & visitors and you’d have a popular subway station.
Hell … maybe Madison Park would finally agree to re-route the 11!
That’s almost the population of Issaquah — and with more jobs…. Just sayin’.
Most valuable budget item of all, Al. But deserves wider focus.
The first decently-paid job in thirty years will with one stroke result in at least the following, state-wide and national:
1. Vaporize all State-wide hatred of Seattle and especially its transit projects.
2. Wipe out national addiction both to methamphetamine and to stuffing prisons.
3. Turn the whole credit card economy, and its every bill collector, over to collections.
4. Give all of Donald Trump’s voters to the kind of Republican like James R. Ellis, who founded Metro Transit.
Or after thirty years without a raise from either major party, at least force the other one to deliver, to the average working person, the things they’ve been promising all those years..
Would save transit a lot of fare-evasion and graffiti-removal.
Mark Dublin
I’ve got to say I’m highly skeptical of this idea. An 8th and Madison station will be adjacent to I-5 on the west, a 10% grade on the east, Freeway Park to the north, and a few blocks of residential to the south. The 5th Ave location simply has better catchment.
The correct place for a First Hill station is at Boren and Madison, which for the listed reasons is a bridge too far. I’d rather consider ditching the Ballard-Downtown corridor in favor of the Ballard Spur and a branch from East Link to SLU under Boren, with the intent of continuing up through Fremont toward Shoreline via Aurora Ave.
Politics will never allow Fremont being served properly. Ballard Subway (aka Seattle Subway) will never allow it.
Um, Les
https://seattletransitblog.wpcomstaging.com/2014/06/23/lets-build-the-ballard-spur/
Yep, a zoo station puts you right in the heart of Freemont.
Are you a fan of this line then?
https://seattletransitblog.wpcomstaging.com/2013/12/13/build-a-ballard-subway/
The Ballard Spur got almost as many riders at about half the cost. And both won’t be built, but not because of Seattle Subway.
A station in upper Fremont versus lower Fremont (yes, they are both Fremont) is debatable. Lower Fremont has a lot more people around it. Upper Fremont connects better with buses and would (presumably) be cheaper to build. ST should study the costs of both. I could go either way. There is potential for the gap between the two to be bridged somewhat by the addition of a bus stop the above the troll (36th). That would enable riders to walk down the stairs (or otherwise get to lower Fremont) after exiting the ‘E’ or the 5.
If not, then you run a bus from the station(s) to lower Fremont. I realize it may sound weird to take a bus from a train station because we have failed miserably in that regard with our current system (which is why it has such pathetic ridership) but not that difficult with any of the stops on a Ballard to UW run. A frequent connector bus from 8th to Wallingford might make a lot of sense (thus traversing all of lower Fremont and connecting two of Tableu’s office buildings). Then again, straight down Fremont works just fine (like the non-express 5).
As for Seattle Subway, I think you are really confused if you think they have that much power. Nor do they strongly favor one stop versus another (lower, upper — both work fine).
The only possible other line Les is referring to is the non-grade separated line C-01-d, sometimes referred to as the 40 streetcar, which almost no one in Ballard or STB supports .
Given the recent proposal to run Easlink through to Ballard, would an aerial green line in south downtown be feasible?
Eastlink will run on the I-90 lanes ramps, which are already coming into IDS at really steep grade using the existing bus ramps. What if instead of going into the IDS, The line were elevated over Airport way and up 5th. New Aerial IDS station to the current IDS plaza and platforms would make a nice transfer. Then the green line aerial alignment could continue up 5th, jog over to 6th (over the parking lots and low rises) then head over Yestler and I-5 and into a Pill Hill Tunnel portal west of Harborview/South of James. If its feasible it could save a lot of money and make the Madison station a lot shallower.
Going diagonally across the street grid doesn’t really work for an elevated line. While there aren’t that many buildings in the north of Jackson part of the IDS, it would still be enormously expensive to buy and bulldoze them. Yesler Terrace is conveniently being torn down and rebuilt right now, so a portal could conceivably be put in, but the developers sure wouldn’t like being told that they have to go back to the drawing board to accommodate new infrastructure, and there’s something a little too familiar about putting unlovable bits of infrastructure where poor people live.
Plus elevated lines are eyesores, and only make it through the political process when they’re in very undeveloped and unloved areas.
With the exception of one building impact, it looks like parking lots between 5th/Jackson and 6th/Yestler.
Unloved, diagonal, aerial routing – just like Downtown Bellevue to Overlake Hospital will be.
“Plus elevated lines are eyesores, and only make it through the political process when they’re in very undeveloped and unloved areas.”
I think this has more to do with the incentives of local residents than with the actual “eyesore” nature of elevateds. If a line is already planned to go through a given area, every existing local resident has a huge incentive to get the city/region/state to fork up extra money for a tunnel, even if the average regional resident would be better off with an elevated alignment that freed up resources for additional infrastructure elsewhere. Of course this is situational, but elevated’s work well in Chicago from my experience.
Thinking about it another way:
The walksheds should be compressed NE/SW, to accommodate for the gradient (and a little more because crossing I-5 sucks, too.
So if you add Madison BRT to the map and look at where you can get with how many transfers, it’s easier to evaluate the tradeoffs. For riders on the downtown side of I-5, you add a transfer to get to anywhere on the green line, but blue-line access remains unchanged. For riders in first hill, you eliminate a transfer going to anywhere on the greenline, and substantially improve a transfer (from green line to blue line vs from Madison BRT to blueline) to destinations on the blueline. It doesn’t quite work.
The improvement for First Hill riders is better for southbound blue line than northbound, both because the transfer is better at IDS than Westlake (assuming the 7th ave station doesn’t move) and because the FHSC and/or walking provides decent connectivity to CHS from the western side of First Hill. I’m not sure, even with the Madison/Boren option, if I’d take the green line to Westlake and transfer or if I’d just walk up Broadway, catch a streetcar if it comes, and use CHS to get to blue line points north.
So I amend my previous statement: downtown riders gain a transfer to get to green line, first hill riders save a transfer to get to green line and south blue line, but south blue line is just West Seattle, and poorly served at that. (not to diminish West Seattle, but both it and first hill are residential centers, and traffic between two residential areas is much lower than between residential and areas with employment and entertainment value.)
Which seems like a wash, to me. If the priority is on getting new parts of town served by some kind of rail, maybe it’s worth it. If the priority is ridership (as a measure of most utility to the most people), it looks like a lot of added complexity and cost for a negligible gain (or maybe a loss).
I agree with your conclusions. Of course, we haven’t seen any ridership projections on these options, but it seems like the loss is greater than the gain.
Shotty, Worst problem with ridership projections is that so far Seattle has never had enough high speed urban transit experience to make any projections possible.
Though I do think first week after first train leaves Husky Stadium for Westlake and points south will advance our calculating skills a lot.
Hate to use this for an example, but I wish the Interstate Highway system’s estimates had fit your calculation.
Though I think Captain, and then General, and then President Eisenhower always intended his highways to prevent an enemy from getting a beach-head on either coast.
Not for helping the whole population both flee our cities and destroy them more completely than any enemy besides the Confederates.
But the real truth is that people our age are either privileged or cursed to at least begin changing the national living patterns of more than half a century.
A brutal but magnificent time to be in public transit.
Mark
I think as the system gets bigger, as long as the transfers aren’t super onerous, few people will care about a one-seat ride on a train running every 6 minutes or better. Transfers will be part of the deal. Ridership will be less affected as the system gets more extensive because everyone will get used to getting to more places using transit. I would still take the Green line to get to the University street area, and just accept the need to transfer or walk… it will still be way faster than the alternatives.
Would it be worthwhile to consider aerial sections of the Green Line north/south of the tunnel to ameliorate the grades of First Hill? I realize the aesthetic issues with this, but sometimes function is more important than form.
Clever architecture could even make the features be symbolic and beautiful.
It’s clear that the hill climbs are the most significant transit rider access challenges anywhere downtown/First Hill east of Third Avenue. Relocating the station will help some but it won’t solve the challenge by itself.
The challenge may be most effectively met by a short line developed mainly to transport people up and down the hill. It’s what the Madison BRT is supposed to do, except the stops aren’t level and the vehicles have cross street traffic to fight. (I do still think that Madison BRT should be thought of as Madison Hillside Tram to more accurately design for what I see as its major purpose.)
The challenge is unique for American cities. The inclines in Pittsburgh, the Portland State aerial cable tram or Angels Flight in LA are probably the closest kinds of solutions.
At some point, level walkways, sky bridges and elevators as an integrated system have to also be added to maximize access.
If we could develop a hill climb system (level walkways with strategically-placed escalators and elevators) on Jefferson Street between Pioneer Square Station and Harborview, and on on Marion Street from a 5th/Madison Station to Boren (probably both crossing over I-5), much of the access problem would be eased.
I would add that inclines or sky cable trams could also be studied as part of these systems.
I like the idea. Transfers are not the end of the world on line segments operating frequently.
In fact, the system voted best Metro in the Americas in 2010 has almost no parallel line segments and relies extensively on transfers.
https://en.wikipedia.org/wiki/S%C3%A3o_Paulo_Metro#/media/File:Metr%C3%B4_SP.png
I’m sure their transfers are better-designed than ST’s, though.
Maybe, but we have to live with our transfers, otherwise we are really blowing a lot of money. As it is, someone will take a look at the current plans and wonder why we don’t just reuse the same tunnel. The short answer is headways. But this new tunnel won’t be very useful to people unless they transfer. Does anyone think that the current tunnel would be good with only one tunnel between Westlake and I. D.? That would have been stupid.
That is why Madison was chosen. Having a station at 5th also provides a bit more of a gap between it and the other stations. But not as much as this would, which means you really aren’t adding much value versus reusing the existing tunnel (if that was possible). This gets people in other parts of the city (that currently take Link or will take the other line) interested in the project. Otherwise, it is simply a line to Ballard and West Seattle (and only parts of those neighborhoods at that).
https://www.youtube.com/watch?v=ybz5KyUo-_E
Glenn,
Though Sao Paulo (“Sow Paulo, or Pauloo) has a fantastic subway system, it also has some great trolleybus things too.
Greatest is the “Fura Fila (see the link to see how great!) a system of triple-articulated trolleybuses on guide-ways.
Seen here demonstrating a passenger spirit that Seattle will have a hard time matching- though race you, Portland!
Notice that the virtual bus with people dancing on the roof has TriMet MAX colors, but that historic Metro brown flower between the headlights. Wondered where we sent it….
Unfortunately:
“Because the city has such a huge urban sprawl, there is another definition for its metropolitan area:
Complexo Metropolitano Expandido, which is the same as a Combined Statistical Area in the United States.
By this definition, greater São Paulo is the third largest city in the world with more than 27 million residents.”
– World Population Review
So my take is that while the greatest transit doesn’t make a dent in urban sprawl, it’s unlikely very many cars jammed in traffic have people dancing on the roof. Though roof scene from this video would definitely get Bellevue out of its cars, both to dance and to flee.
Mark
When I was there in 2000, there were only two Metro lines. The others were built very fast.
Brazil has a general transportation tax that strongly favors consolidating things in large urban areas, so stuff tends to strongly favor the creation of large cities.
São Paulo has sprawl I suppose, but there is only so much you can contain a city that has approximately the same population as California. Huge parking lots on the surface are very rare there. Huge plazas for people in places.
They have a central business district too. Avenida Paulista if I remember right. You won’t find multiple Metro lines going there. It was considered for more important to spread the service to areas without it than serve one area multiple times over.
I guess I’m in the minority in not being particularly fond of this idea. The line should be designed on its own merits according to ridership, cost, etc., not as an attempt to “right a wrong” from a decade ago. I’d much rather see the new tunnel effectively serving the CBD, where ridership is highest, with fast and frequent BRT lines (and eventually Light Rail) along madison and Boren to serve the hospitals.
Now, if, and only if, transfers were extremely easy and seamless, I could see the Boren departure working for North Seattle Residents.
The advantage of this proposal (if it is feasible) is not to right a wrong, it is provide a much better value for riders. Transfers are a given. That is why this line only has one station between Westlake and SoDo, and that one station is Madison (a station that the current tunnel lacks). If the idea was to maximize the one seat ride experience, it would simply have all the same stations. With that in mind, a station like this, if it is practical, adds substantial value for everyone. I doubt someone would transfer at Westlake just to get to Madison (University Station is not that far). But 8th and Madison is a lot farther.
I should have said that this line has one stop between Westlake and I. D.
I don’t think it’s that big of a deal to transfer to go to the other downtown stations either. Look at the Prague subway as an example. Three lines run through the city center forming a triangle. There are transer points for each combination but they never interline. Not every center city station is covered by any one line. I lived there for about 6 months many years ago and the transfers were not really an issue… or you could avoid the transfer and walk.
the wrong was not including a high transit potential neighborhood. righting the wrong is including a high transit potential neighborhood in st3. ofc if the tunnel returns bad ridership numbers, it should be rejected.
Good post, Martin. This idea was discussed by the folks who took a look at the WSTT idea before it went public. The guy known as “d.p.” suggested it. I believe he suggested 8th. I really like the idea, and suggested Boren. Ultimately the folks in charge decided not to muddy the water too much with the WSTT proposal and just stick with 5th.
One advantage of Boren is that it could provide for an intriguing bus route. I’m thinking of a bus that travels along Rainier (like the 7) but instead of taking a left on Jackson, just keeps going on Boren, skirting the hill. It could go all the way to Fairview, providing a good connection to South Lake Union. Of course you would have to do some work to avoid getting it stuck in traffic, but that might be easier than say, fixing the 8.
If true, then it’s ironic the guy that banned d.p. for life gets to run with the idea.
Does STB have any get out of jail cards?
What if this new tunnel took the Green line to Ballard via Belltown? Could the new tunnel split into two lines after Westlake so the Ballard line could continue to Belltown and Seattle Center/Queen Anne. The other prong of the split could continue to SLU in a stub tunnel where the East Link trains could terminate and head back to Redmond. Eventually the stub could continue north along the 99 corridor serving both upper and lower Fremont, Greenwood, Aurora Village and so on.
This connects East link directly to SLU and prepares for a future line without the need to build a third downtown tunnel when we decide in the future a 99/Aurora route is needed.
I think that’s a super interesting idea. You make a 3rd downtown tunnel that cuts across SLU, Cap Hill and ends up in the ID on it’s way to OTC. The 2nd tunnel will go along Belltown and downtown on it’s way to the airport.
Well not quite. Capitol Hill and the north portion of the red line would still be served by the Current downtown tunnel. East link would eventually use the new tunnel that would include (from South to North) ID, Madison St, Westlake, Belltown, QA/SC, Interbay, Ballard. Between Westlake and Belltown there would be a junction where the blue line (East Link) would split off toward SLU.
For getting under I-5 it might be possible to use the relatively new ground freeze and tunnel method. You freeze the ground to make it rock hard, tunnel through it usung rock tunneling methods, then insert the concrete support structure. When you let the ground thaw the structures above now have support around the tunnel to take the place of the ground that is gone.
I think the Green line alignment should stay west of I-5 and have Madison station serve the financial district. But while building it, it might be useful to allow for a junction toard the east that in the future could cross under I-5 and serve First Hill, then headed south along Boren/Rainier to have a transfer at Judkins Park station and join up with Central Link near Mount Baker station.
Of course, if the Green line was completed around 2030, this additional line would be farther into the future.
The problem with these types of proposals is that, with I-5 and the grade, the geometry of serving First Hill and westlake and IDS is very difficult and thus probably wouldn’t pan out from a cost benefit perspective. The way to make the lines work is to remove the emphasis on IDS, and reroute the Green line to connect with East Link via First Hill, Squire Park and Little Saigon. Such a line would have a transformative effect on mobility in those neighborhoods at the cost of the additional tunneling and marginally worse connectivity between eastlink and other southern rail segments.
The idea of a diagonal through First Hill to SLU is certainly an interesting one, Alex and simpler than the full “Metro 8” proposals. However, you will get one gigantic blast of “NOOOOOO!!!!!!” from East King if you propose routing the Blue Line away from the financial district. Eastsiders have no other reason to come to Seattle and are, aside from Maple Leaf and Broadview, the major workforce in the legal/financial core.
Everyone, please remember that what is being discussed in this thread is a smaller version of Option 25 from the ST working group. It was dropped early and with no explanation which should tell everyone what its reception will be at SoundTransit.
With the caveat that I don’t know how many eastsiders work in the financial district vs. First Hill I don’t deny those political considerations. I rather wanted to note the easiest way to get around the technical constraints around serving First Hill as part of the green line. Moreover, every line is better off with a downtown connection but in sum the system and especially the northern lines are worse off without HCT access to those east of I-5 neighborhoods
I’d also note that the green line doesn’t have to interine with eastlink as long as ST can figure how to get 2 minute head ways in the DSTT, A problem that seemingly every other subway system has managed to solve.
Having the tunnel veer out like that would also reduce construction complexity due to avoidance of the freight tunnel and skyscraper foundations right?
No, it’s just the opposite. The freight tunnel is never east of Fourth Avenue and “skyscraper foundations” do not intrude into the roadway. They go straight down from the building envelope.
But “skyscraper foundations”, and the supports for I-5 would be more of a problem with the cross grid curves at the north end of downtown, especially from a Boren Avenue station option.
1/2 mile walksheds are unrealistic with the topography and with this little thing called I-5.
I’d say keep the station west of I-5. After all, what’s the point of calling it a “downtown” tunnel if it has a stop in First Hill?