Northgate Link TBM 1 (Brenda)

At around 1:20 p.m. Tuesday afternoon, the cutterhead of TBM #1 (formerly known as “Brenda”) was lifted out of a 95-foot deep retrieval shaft just north of the University of Washington Link station. The 21-foot diameter cutterhead is the first part of the machine to be removed from UW Station, a week after completion of the northbound Northgate Link tunnel.

The cutterhead will stay put at the UW Station staging area, easily seen from the pedestrian overpass, until early next week, according to Sound Transit. Over the next few weeks, contractors will continue to remove other parts of the machine and transport them to a lot near Rainier Beach Station.

During that time, Sound Transit will inspect the TBM and determine whether or not it could be used to dig the last segment of Northgate Link’s tunnels, the southbound tube from U District Station to UW Station. TBM #2 (formerly “Pamela”) is still undergoing refurbishment and repairs at U District Station after arriving on March 24 despite suffering minor damage and figuratively limping to the station. Mining of the segment is expected to be completed by the end of the year, with a hole-through at a further date.

In late 2011 and early 2012, Brenda was twice lifted out near Convention Place Station after the completing the Capitol Hill-Westlake segment of University Link.

17 Replies to “TBM 1 Cutterhead Removed from UW Station”

    1. I’m afraid you’re right, Charles B. What happened was that late in 2015, an ill-advised automation experiment resulted in Bertha repeatedly digging her way to Convention Place before anybody could even find her. The alleged “sink-hole” was only a cover.

      Naturally, Uber, Lyfft, and Amazon realized that their algorithm (or is it a paradigm?) needed recalculating. But main reason for the secrecy was that they were afraid that the public would find out about their plan to turn giant boring machines into drones for carrying passengers or delivering packages.

      The helicopter blades were already a bad enough problem. But much worse would be ticking off the thousands of customers who had already signed up for the service. Can you imagine the size of a smart-phone these people had already had to buy for the APP?

      Still and all. The dream of curing congestion, never wavers. The ability, in the same trip, to defy both crowded freeways, and skies, without light rail, is too powerful to defeat. Incidentally, anybody into casting. Beautiful piece for a necklace.

      Would be great to make the thing with little beads for every individual part. Also great contest between old-fashioned carving and 3D print. Meantime- yeah, Amazon, I’ll just come in and pick it up myself.

      Mark

  1. Is this the same Brenda that dug both the U-link and the north Link tunnels, or are they different TBM’s with the same name?

  2. Put that cutterhead (formerly known as Brenda) in the Cutterhead Hall of Fame, at least until ST3 gets passed and we need some more boring.

    1. The TBMs are owned by the contractor and custom-built for each job, and are usually too worn out to be reused for another job, although they can scavenge parts from it. TBM1’s reuse in this case is a small final part of the same job, when the other TBM is sick and needs a rest, and building a third TBM would be hugely expensive.

      1. They have a 3rd TBM already. They had a spare for NG-Link.

        Brenda has now dug both bores from Cap Hill to Westlake (stub tunnel), and has dug the entire NB bore from Northgate to Husky Stadium.

        She is a champ.

        The question now is, “Will she also be asked to dig the final remaining NG-Link bore from U-Dist Station to Husky Stadium (southbound bore only)

  3. By the way, Bruce, thanks a million for this posting. I was planning to come up to Seattle anyhow. Wouldn’t miss this for the world.

    Mark

    1. It isn’t, and at this point we are so far from the completion of heavy construction that there’s no way to guess if it might open early.

      The in-service target remains September 2021, and the project has 165 days of float. From where we sit now the best-case scenario is a repeat of U-Link, where they were able to advance the opening by roughly 6 months.

  4. A thought for you: ST has gotten pretty good at the process of tunneling. (I may have my issues with where they decide to put the tunnels, and how many stations they dig along the way, but I have to admit, that once they start digging, it seems to go quite well).

    So, they have a lot of in-house expertise they’ve built up managing projects like this. But, tunnel 6, the last tunnel between U district and Husky stadium, will be done soon (EOY, per this post). After that, there’s a very short tunnel in Bellevue (is that bored or cut-and-cover, though?), and then we’re done with tunneling for any project currently funded.

    If ST3 passes, the earliest any new tunnel will open is 2033. Walk that back 5 years, and you get that we’re not digging again until 2028. A solid 10 years after our last tunnel is dug for ST2.

    What will happen to all that in-house expertise that ST has built up? Will they do something else for 10 years? Or will they go an get new jobs? I know contractors are doing the actual running of the machine, but I’m talking about the expertise required to oversee the projects.

    1. This is a good point. I’ve seen the claim that part of the reason NYC’s MTA has gone so far over budget and behind schedule on major construction projects during the past decade (the 7 extension, 2nd Avenue subway, East Side Access) is that it had been so long since the agency had worked on a large project that they’d lost much of their in-house expertise in managing major tunneling projects.

    2. Given that the 2nd DSTT will likely begin engineering work immediately after ST3 passes. I am confident ST will retain the talent. 10 years of prep for major work is not too much for a team to keep being excited — it’s a major and prominent project for anyone’s resume.

  5. You can see TBM #2 (Pamela) from the U Dist camera. She looks like she is in place to dig, but I would presume that that is also the best place to assess her condition.

    Is it possible that the contractor would mix and match parts? Like remove TBM #2’s cutterhead and swap it for TBM #1’s?

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