Second Ave. Sagas

Second Ave. Subway drilling sagas

Written by

Benjamin Kabak

in

As above-ground complaints about the Second Ave. Subway are making headlines, underneath the avenue, progress on the tunnel is continuing apace. When we last checked in on Adi, the TBM drilling out the subway tubes, it had reached only 90th St. and was drilling an average of just 14 feet a day. In August, however, the MTA was able to pick up the pace.

Late last week, DNA Info reported that the TBM had drilled through 1760 feet of rock in August and had nearly reached the 2000-foot mark. Today, the MTA confirmed that the machine has reached 1928 feet. Meanwhile, Ben Heckscher at The Launch Box notes that the TBM is moving faster than expected. Last week on one day, for instance, the TBM mined 92.74 feet, and yesterday, the machine dug out 74 feet, ell above estimates of 50-60 feet per day. Adi is now somewhere underneath 84th St., approximately a mile away from its ultimate goal of 65th St.

In other Second Ave. Subway TBM news, Wired magazine went underground this week with a slideshow feature on the tortured 75-year history of the new subway line and the technology behind the tunnel boring machine. Since the photographer took his shots when the media took a trip in the launch box, the photos are similar to the ones I presented in May, but with one amusing difference: I accidentally appear in one of Wired’s photos.

Comments

11 responses to “Second Ave. Subway drilling sagas”

  1. JoshKarpoff

    Using my public construction project planning skills and MTA planning documents, let’s do some quick estimates.
    So let’s say that the TBM is able to sustain these levels of production. That means that the first of the two drives would be done in roughly 2 months from now, around Halloween. It would then take approximately 1 to 2 months to re-launch the TBM for the second drive. Give that drive 3 months and you’re looking at tunnel mining possibly being complete in March 2011. That leaves 5 and three quarter years to mine out the station caverns, build the station structures and fit out all of the systems and interiors. That seems very reasonable for a large public construction project and would certainly help to get the project back on schedule.

    Once the station caverns and such are mined out and the larger equipment for each station (transformers, air handlers, escalators, etc.) are lowered down, the contractors could even start to restore street level to significantly less of an eyesore. Maybe even by the end of 2013.

    Reply
    1. Benjamin Kabak

      I don’t think the MTA can sustain that pace. As it is, they don’t plan on completing the second tunnel until the end — and not the middle — of 2011. But if somehow the timeline speeds up, I don’t think anyone would complain.

      I’m not quite sure the why of the FTA’s 2018 estimate, but it’s not unreasonable to think it could actually wrap by 2017 instead.

      Reply
  2. Jerrold

    Ben, why are they saying 65th St., instead of 63 St.?
    I mean, is there already a cavern dug there from 65th St. to 63rd St.?

    Reply
    1. Kris Datta

      65th St. is likely where the Q will end up after it curves northward from the 63rd St. tunnel.

      Reply
      1. mike

        I believe Jerrold knows that, and is asking the question as a result. Is there an existing cavern from 63rd to 65th? In other words, since the Q will eventually run from 63rd to 96th — and the current TBM will stop at 65th — is the 63-65 chunk already dug out? Alternatively, is the “65th” report just a typo or misstatement?

        Reply
        1. Jerrold

          Thanks, Mike.
          Yes, that’s what I meant.

          Reply
        2. Peter

          Jerrold,
          You are exactly right. When the 63rd Street tunnel was constructed, the provisions for connection to a future Second Avenue line were also build.

          If you ride a Queens-bound F-train, and look out the right-side windows when you are a few hundred feet past the Lexington Avenue station, you can see the connection to where a northbound Second Avenue train would join the Queens-bound service. The curved tunnel ends at a wall at about 61st street or so.

          Use of that segment would require what is now called Phase III of the SAS to be built.

          The corresponding junction from the north, at about 65th street, and where the TBM will stop digging, is currently not visible. It joins the tracks that are hidden behind the false wall on the upper level.

          From Wikipedia:
          http://en.wikipedia.org/wiki/L….._Subway%29

          East of this station, the planned track connections to the 2nd Avenue Subway curves slightly north and ends with a bumper. After the tracks end the roadbed goes on for a few hundred feet and the the smooth cement wall floor and ceiling come to a stop.

          Hope this helps.

          Peter
          inklake

          Reply
    2. Scott E

      Nope, I don’t think this part isn’t dug yet (the curved stretch between the 63rd/Lex station and 2nd Ave). But this piece is quite complex: it includes the junction between the 2nd Ave (T) and 63rd St (Q) lines, transitions from side-by-side to top-and-bottom configuration (63rd St station layout), and winds around the nearby F-line tunnels to Roosevelt Island and the new LIRR tunnels to Grand Central Terminal. Maybe a TBM can’t safely handle these maneuvers and pieces will be mined. I really don’t know.

      Besides, Lexington Ave-63rd St is an active station. While I like to picture the TBM busting through the wall of the station like the Kool-Aid man (flashback to TV commercial in my childhood), I don’t think that’s going to happen.

      Reply
      1. Andrew

        I don’t think it’s quite as complicated as you make it out to be – the Q tracks will be north of the F tracks on both levels, so they won’t need to cross. I’m not sure where exactly the future LIRR tracks fit – underneath both levels, I suppose?

        There’s no need for a TBM to enter the active station. The tracks already exist behind the wall; I think they end not far from the east end of the station. They’re currently used for layups. Of course, at some point the wall will have to come down.

        Reply
  3. Mike

    Ben, I’m with Jerrold…Any idea why?

    Also, are you of the opinion there is no way this project is going to be done by 2016? The MTA is still sticking by their deadline…

    Reply
  4. Ben

    As I’ve posted before, it’s the surface work and station construction that’s put the project in jeopardy. The Sand Hogs are professionals and will get the tunnels done. It’s Skanska and the other contractors rerouting the utilities and the lawyers (who had been holding up the project for petty reasons) who continue to jeopardize the project. I said recently that the tunnels will be dug, and then they’ll sit there waiting for the shenanigans to get around to rerouting the utilities and building the stations. It seems that somebody recently kicked somebody’s butt, because there’s much more work going on at the 96th Street Station site, and the 86th Street Station site…until a couple of weeks ago, they were phantom projects with phantom workers and equipment stuck at dead standstill. Now, things are moving. I guess somebody figured out that they can’t delay forever, because the machines are digging the tunnels out, and it’ll be pretty obvious that they have been shirking their responsibilities. Half of 86th Street and the sections south of that are still a charade. At present, the plan they’ve got is the plan they’ve got. Get to work to reroute the utilities. We’ll wait until 2020, or forever…with the tunnels dug…and no stations…at this rate.

    Reply

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