Second Ave Subway Construction thru Phase I open

Everybody take a deep breath.

Why are we trying to figure out stuff that's already been decided by people who aren't us?

-otto-

How is the SAS planned to be routed south of Houston St? Will it tie into the existing Chrystie St tunnel used by the B and D lines, or use a new tunnel? I suspect tying it in for that short a distance its probably not worth it, other than providing some new routing possibilities, given the complications e.g. new junctions, etc.

Jon

"jonnhrr"
How is the SAS planned to be routed south of Houston St? Will it tie into the existing Chrystie St tunnel used by the B and D lines, or use a new tunnel? I suspect tying it in for that short a distance its probably not worth it, other than providing some new routing possibilities, given the complications e.g. new junctions, etc.

The track schematics can be seen here (82.5 KB PDF file) and here (75.9 KB PDF file). The plan and profile can be seen here (554 KB PDF file).

The track and platform configuration at 72nd Street has been modified and can be seen in pages 4 and 5 here (7.32 MB PDF file).

Thnaks for the info John.

With the contraction to 2 tracks at 72nd street, I hope they are no cheapening the project at the expense of future capacity that will be hard to add once the tunnels are dug.

Jon

"jonnhrr"
Thnaks for the info John.

Your welcome.

With the contraction to 2 tracks at 72nd street, I hope they are no cheapening the project at the expense of future capacity that will be hard to add once the tunnels are dug.

From my view I happen to believe the #12 turnouts will allow trains to pass through the junction faster then the previous configuration that employed only #8 turnouts. Do note that there is 2 place in the modified configuration where trains can be relayed, in the previous configuration there was only one.

There is a lengthily discussion on this matter at subchat.com in a thread titled Second Ave Alignment Change. I will leave it to you to decide who's blowing smoke and who is not.

If I may put up a superfluous question, I would like to know just what will be done with the TBMs after they finish drilling the Phase 1 section. Last I checked the remaining four phases of the project are all unfunded and it is also my understanding that the TBMs will be dismantled after they pass 63rd St, especially since it may be some time before they can start working on the next phase of SAS. So, will these machines have to be purchased and assembled again? Even if they would get the funding for the next phase ASAP, the TBM work is currently southbound...
I just don't see the MTA receiving the necessary funds to continue work on the whole of the SAS any time soon so I'm just curious as to how the major construction equipment is to be dealt with in the near future.

"marnegator"
If I may put up a superfluous question, I would like to know just what will be done with the TBMs after they finish drilling the Phase 1 section. Last I checked the remaining four phases of the project are all unfunded and it is also my understanding that the TBMs will be dismantled after they pass 63rd St, especially since it may be some time before they can start working on the next phase of SAS. So, will these machines have to be purchased and assembled again? Even if they would get the funding for the next phase ASAP, the TBM work is currently southbound...
I just don't see the MTA receiving the necessary funds to continue work on the whole of the SAS any time soon. . .

According to Second Avenue Subway; Tunnel Construction Techniques (655 KB PDF file) and this document that I linked to in my post above, phase II will not make use of the TBM that will be employed on phase I. Phase II will likely use a Earth Pressure Balance tunnel boring Machine (EPBM). There are a couple of those that I know of floating around here in the United States. Phase III will employ the same type of TBM that will be used on phase I.

. . . so I'm just curious as to how the major construction equipment is to be dealt with in the near future.

This would totally depend on if there is a need for this particular machine elsewhere on the planet. Otherwise it maybe mothballed south of 63rd Street or dismantled and stored waiting to be called for work elsewhere.

I will note the TBM that was use to bore the A Route Red line on WMATA metrorail between Rock Creek Park in Washington DC and Pooks Hill Road in Bethesda MD was previously used in the construction of a particle accelerator in Texas.

TBMs are rarely abandoned these days, except in odd situations. All TBMs can be refurbished and used again. The ESA rock TBMs include a rebuilt unit.

-look at the construction schedule for the LIRR Grand Central Terminal extension. In little over a year, two tunnels will have been bored from 63rd st. to near 42nd. st. The Second Avenue Subway is plodding in comparison.
-how fast could they complete the Second Avenue subway if more drilling machines could be put to work? The modern technology is awesome. They could head downtown too.
-granted a slow pace is far better than no pace, but the line is being built so gradually it is almost as if they never planned to use it. In the meantime bigger and fuller apartments keep going up all over the East Side, hopelessly packing the Lexington Ave subway like sardines.
Have you looked at Harlem lately, or along the East River?
-before we start worrying about extensions to the Bronx, or wherever, how about just finishing the East Side from 125th to Wall St. ?

Roger

Wallyhorse wrote:Roger:

I agree the SAS needs to be done, and that is why I have been saying they need to look at doing a Nassau Street connection if that can speed up the start of service to lower Manhattan if possible (and also give the SAS a second lower Manhattan route and access to Brooklyn, which would help tremendously between Atlantic-Pacific and 125th).

I also think they may need to extend Phase 2 to where it goes all the way across 125th street to Broadway, so it can double as a 125th street crosstown which likely will be needed by the time such could be built with Columbia expanding as it will be over the next 15 years.

I'm beginging to beleive that a 125h street line is a bad idea if built right away. It would be build right on top of the most active fault line in the area. construction in that kind of enviroment is a much more delicate task. Do one thing wrong, you could litterly cause and earthquake. this fault has been known to cause earthquakes of 4.0 to 5.0 on the Richter scale in the past, and has produced some 1-2 magnitute events over the last few years. I think it would be best to bring in speicalized equpiment, matterials and personal for such a job as a phase 5, rather than just keep on going under phase two.

I've read the replies in this thread on this matter, and the newest version of my fantasy map addresses these ideas, particularly the ones about branches of the SAS/extensions into the outer boroughs. There are two versions. One without Queens Blvd super express tracks