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Graphic by the author (unofficial)
Graphic by the author (unofficial)

Late Friday morning, Sound Transit’s tunnel boring machine ‘Brenda’ holed through at the future University District station at NE 43rd St & Brooklyn Ave NE. The machine took 6 months to tunnel the mile between Roosevelt Station and the UDistrict and will be refurbished before digging the last mile of the northbound tunnel to UW Station.

The holethrough comes as Northgate Link’s TBMs have struggled with soil conditions, premature cutterhead wear, and slower than expected progress. The unmitigated success of ULink’s tunneling has set the bar very high for this project, and it’s not unreasonable to expect occasional setbacks, which is precisely what schedule float is for. The project is still well within its schedule and budget, with several months of project float remaining. (The Sound Transit Board heard a more detailed briefing on these issues at its October meeting, and those materials are not yet online.)

Meanwhile, TBM Pamela is busy digging the southbound tunnel, and was 600′ south of Roosevelt as of the last briefing on October 22., having just passed under Ravenna Boulevard as of the last update on October 31.

59 Replies to “Brenda Holes Through at UDistrict Station”

  1. Isn’t Pamela a bit further along? The last update from ST stated Pamela had passed under Ravenna Blvd already. That’s at least 1/3 of the way to 45th St isn’t it?

      1. Thanks for fixing it. It might be worth perma-linking the most current Light Rail progress graphics on the front page of the blog. ;-)

  2. Great news ! Glad to see her face again!

    Pardon a naive question; a date for UW Link open ? I can deal quite well with Metro to there as it is.

    1. Not a naive question, as no date has been set. Bus service will change to feed Link starting on March 26, but it’s possible that Link may have a ‘soft open’ a little bit before that.

      1. The sooner they open UW Link, the more chance to get the impression out there to less enthused seniors and the “one seaters” that all fears for naught.

        The closer to actual Metro change date, the more any little glitch becomes “we told you so”

      2. Interesting tidbit – if you look at STs August Agency Progress Report, in University Link, and in their project management chart, it says Revenue Service Est – March 2 start, March 31 end. August is their most recent progress report.

        I know you should take that with a giant crystal of salt, but if you were hoping that Q1 meant January, I think that’s unlikely.

        I also heard twitterings that it will open during the weekend.

      1. Plus both KOMO and KING snarked about Bertha during their news reports tonight, “And no, these machines can’t go replace Brenda once they’re done. Don’t worry, we asked.”

  3. From what I understand of it, Brenda basically ran into a boulder field and they decided to be cautious and slow her down a bit. And they had to do a little extra work on her teeth along the way.

    That said, working on teeth is classified as “routine maintenance”, and although they had to do a bit more than they originally expected, she still is trending ahead of schedule (just not as far ahead of schedule as she was originally).

    Pamela is also trending on, or ahead of schedule.

    ST is sort of making this whole TBM tunneling thing look a bit ho hum….

    Now what about Bertha…..?

    1. “The Chunnel: The Amazing Story of the Undersea Crossing of the English Channel” by Drew Fetherston

      Because so much of our regional transit system will be built underground in our lifetimes, this is well worth reading for whole STB readership.

      Written in plain non-technical English, it makes facts of tunnel boring very clear. Including screaming fights at top management meetings. In both French and English. While Irish laborers were digging horizontal emergency walkways with hand-held air-driven jack-hammers.

      But book deals especially the ramifications of not being able to see through the ground. At least one of their boring machines had a hollow drill through the center of the cutter, with a conveyor belt that brought in samples of the fossil sea-shells in the chalk ahead of the machine.

      A geologist constantly analyzed these samples to make sure the machine was on course. The layer of chalk – reason the famous Cliffs of Dover are white-that could be bored through without cracking was vertically very narrow.

      Meaning that a few degrees wrong angle could drown the whole shift. The MAX tunnel under the Portland zoo lost a year’s schedule because, I think, the crew hadn’t dug the machine far enough into the rock to start boring. And we hit flowing water under Third Avenue at Century Square.

      So if Bertha’s crew knew the piece of metal was in front of them and tried to bore through it- or if somebody else knew it was there and didn’t tell the crew- somebody can and should get blamed.

      But it’s not fair to compare progress on one tunnel with that of another one. However: lawn-owners aside, real moles could possibly be of some use for finding their way underground. Just so they don’t escape under a golf course.


      1. Have been quite some number of times a user of the Chunnel both auto and rail. Like all future users of ST TBMs efforts, just really glad it got done!

      2. I went to a fair number of the citizen advisory committee meetings during the late 1980s and early 1990s when the lines on the map for the westside MAX line were being drawn.

        The line was finished on time and under budget according to TriMet literature.

        However, the year delay that you are thinking of happened in the course of those citizen’s advisory committee meetings. The problem was the course of deciding what it was that should be built.

        What TriMet got from the regional planning agency was a surface line that climbed the 3 mile long 7.5% grade of highway 26 and then ended at 185th Avenue.

        I’m pretty sure everyone knew that the tunnel would be a far better option. They did ridership analysis and, surprise surprise, ending the line in the middle of nothing (and there was far less at 185th then than there is now) had far lower ridership than if they extended the line all the way to Hillsboro. Hillsboro actually has a reasonably active downtown area. It was no modern day Ballard but with Tektronix, Intel and several other microchip plants being built surrounding the city it looked like it was headed that way.

        So, they took an extra year or so to work with that “preferred alignment” and really show, using ridership numbers and other figures that the tunnel and a line all the way to Hillsboro was a far better choice. It was far more expensive, but it was far better than the “preferred route” that TriMet had inherited from the planners.

        The real problem they faced was that the preference in the federal formulas always favors the cheapest alignment. Tunnel vs. surface doesn’t work with this formula. There have to be significant advantages to tunneling. Today, there is no question that the tunnel saves a huge amount of money in operating costs because, even though the tunnel is steep, a surface line would have been far worse. The estimate at the time was that the tunnel would save 3 minutes of travel time over the surface alignment, and with the blue and red line trains going through the thing every 3 minutes or so those extra 3 minutes add up.

        However, the decision makers that were in charge of deciding that this was what needed to happen only looked to capitol cost rather than annual operating expense.

        What wound up clinching the deal was they brought in a consultant that went over the geology of the canyon along highway 26 with a fine toothed comb, and produced a set of plans in how a line could be accommodated on the surface *and* deal with the potential landslide issues and deal with the visual impacts of adding a huge set of concrete retaining walls into the canyon to get a MAX line in there.

        The cost of doing all this mitigation was enough to push the cost of the surface line above the cost of a tunnel, and we finally got something that the decision makers could agree would work. It meant dealing with the paperwork required to change the “preferred alignment” into something completely different, but most of the decision makers were comfortable with that. Even then, though, at least one of the board members kept badgering the TriMet planners about how unnecessary all the mitigation work would be. “How necessary is all this work anyway? Can’t it be done cheaper?” The response from the TriMet planners was “What more do you want us to do? We hired a consultant that knows these issues well and this is the result of their work to estimate what would be necessary to do.”

        Once construction started, there really weren’t that many issues. The one issue they had with the tunnel was that there wound up being a huge chunk of Columbia River Bassalt that was larger than what was expected (the expected to hit some on the west end, but not as large as they wound up hitting). The plan had always been to use conventional drill and blast tunneling with that particular rock strata, since nobody had ever attempted to use a tunnel boring machine in something as hard as fused lava before. The tunnel contractor wanted to try, but TriMet decided to just have them do a longer section of drill and blast.

        Then, the private cemetery above the tunnel got into the act. They claimed that the blasting would cause unnecessary suffering to the dead bodies they had all over the ground above the tunnel. They claimed the dead were put there with the idea that they would rest in peace eternally, and blasting 100 feet beneath them most certainly did not provide them with this eternal rest. Oddly enough, the dead apparently continue to rest there rather than coming back to haunt any of us, but maybe the money TriMet had to pay to the cemetery owner for damages made them rest a bit easier.

        There have been several landslides along the canyon section of highway 26 since then, underscoring how good an idea it was to put the line underground rather than try to stabilize a narrow canyon that was never really big enough for 7 lanes of freeway it currently has been carved into having.

        In any event, the real lesson for SoundTransit and Seattle: if possible you really should get that preferred alignment right. However, even if you don’t get the preferred alignment right it is possible to change it as long as construction hasn’t started yet. It may add a year to the project due to the added meetings and paperwork if the Environmental Impact Statement comes forth showing that the original preferred alignment is a mistake, but if the proposed line must be changed before it is built it is far better to do it then that put up with a century of a line that was a mistake.

      3. Compare the segment of Boston’s Big Dig tunnel (along the waterfront near historic buildings) to Seattle’s AWV relacement. That segment of Big Dig replaced an overhead highway with a cut-cover tunnel routed between rather than beneath these vulnerable old buildings. Unlike a cut-cover tunnel which compacts soils beneath and above, and stabilizes soils alongside, the Bertha tube guarantees settling damage that will inevitably condemn and demolish both historic and modern buildings above its entire length, and in earthquakes could cause sudden collapse with a death toll. Now plug your ears and say, “La la la, la la la. I don’t hear you.”
        Seattlers, meh.

    2. …And Pamela apparently had to miss a 72inch sewer line under Ravenna. You don’t want to be hitting that.

      1. As did Brenda. The sewer line was a known feature to be worked around. I think they probably went slower near it, but it hardly was a surprise.

    1. And also not tell anybody ’til the crew dug a shaft to come up of a beer in Ballard.

      Where they would be transfixed with awesome reverence at the density. Good thinking!


    2. Wouldn’t it be great if some drunk kid took inspiration from last week’s garbage-truck hijacking, broke into a TBM control room, and took it on a joyride under the city? We’d have to straighten out some twists and turns and add stations, but what a head start it’d be….

  4. Yay! Sound transit has a much better track record tunneling than SDOT, which is excellent. Hopefully this extension stays ahead of schedule too!

    1. I think you mean WSDOT. The Hwy 99 tunnel is not a Seattle project, it is a state of Washington project.

  5. If it took six months to dig the mile between Roosevelt and U District why are they anticipating a year for the mile between U District and UW?

    Is there some issue with soil types, noise/vibration restriction, ground water, etc in that area?

    1. Ask ST about all the issues they face dealing with the UW on the tunnels! I’m sure they are taking all the time they need to avoid further problems.

    2. They’re probably required to dig at a much slower pace under the UW campus to reduce risk vibrations.

    3. Remember, they are still ahead of schedule on the current segment. If they are also ahead of schedule on the next segment then it will be less than a year. And that year which is planned probably contains certain overhead items.

    4. Vibrations, as in upsetting the seisemic recorders in south campus and whatever research or earthquake monitoring they’re doing…

    5. Oh, and it is probably a year for both machines to complete their journey. So far in 6 months only Brenda has made it to U-Dist, For both machines to get their it will probably be closer to 9 months.

      My understanding is that the UW gave ST a 10 month window to bore under campus. So everything kind of sort of lines up schedule wise.

  6. What happens to Brenda and Pamela when they reach Husky Stadium? There is no surface access to remove them, and the tunnels to Capitol Hill will have trains running through them.

    1. Apparently there is already a vault at the end of the ULink tunnel to remove them from. Currently covered in the parking lot of the UW Stadium I gather?

      1. Actually in front of Husky Stadium. There is an area that Is temporary pending removal of the TBMs. All this needs to be done and buttoned up between football seasons.

    2. Baselle, after digging the Downtown Seattle Transit Tunnel, the machinery of the boring machines was removed, and the round metal “shields” were sprayed with concrete and became part of the tunnel walls.

      Mark Dublin

  7. It’s really confusing having both “UW Station” and “U-District Station.” Is there a reason it can’t just be called “NE 45th street station”? MAX uses street numbers in its station names. Does ST have some sort of animosity toward street named stations?

    1. The station is for the neighborhood, not just for one street. I like neighborhood names, and it also fits with Seattle’s culture which has always been strong on neighborhoods. And it helps people who want to know how to get to the U-District, which is thousands of new students every year and visitors throughout the year. ST’s original proposed name was Brooklyn Station, which is the avenue in front of it and the former name of the neighborhood. But one U-District activist kept insisting it should be called University District Station, and when ST did a public survey that’s what 3/4 of the respondents preferred, so it became U-District Station.

      I agree that three stations with University in their name is confusing, but UW Station has some responsibility in that, since it’s at the far furthest corner of campus in the middle of nowhere, so not much of a gateway to the university. As for University Street Station, ST has mentioned asking the county to consider a name change but so far nothing has come of it.

    2. Ya. A disaster. We now University Station, University of Washington Station, and U-District Station.

      ST should have stuck to their guns and struck with Brooklyn Station, but the local business community thought that U-Dist Station would be good for business and did e full court press against ST. ST caved.

      What can you say.

      1. I’d have preferred Husky Station and U-District Station, especially since the current “UW Station” will serve most of campus so poorly.

    3. My solution: Keep U District the same, rename UW (2016) to UW-Husky Stadium (note the dash), rename University Street to Benaroya, Financial District, Arts District, Harbor Steps, or whatever else.

    4. “it’s at the far furthest corner of campus in the middle of nowhere, so not much of a gateway to the university”

      Let us contemplate that. A person cones to the university for the first time. He chooses “University of Washington Station” because it’s got the full name of the university in it. When he come out the entrance, he may or may not see the stadium (I’m not sure if it’s beside or behind him). The bridge is right in front of him, which is good, and he sees some college-looking buildings in the distance which suggest which direction to go. The next thing he sees is two large streets with some ten lanes of cars; a car sewer. Then he walks across Rainier Vista, which is beautiful, but he might be disappointed that he;ll have to walk across this car sewer and emptiness every day just to get to the nearest college building, to say nothing of the building he’s going to.

    1. Why aren’t the tunnels being dug north? Couldn’t service be added as the boring machines reach the stations?

      1. Yes!!
        I live next to the u-district station and it drives me crazy that I’ll have to wait until the whole north gate extension is completed. However, I bet it’s because they need tracks to turn the trains around and they may not want that at every station. Not sure though. Any takers?

  8. In the photo on the left, is that woody debris in the material being ejected from Brenda? I didn’t realize you’d encounter that many recognizable tree parts down there, if that’s what it is.

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