Amtrak Gateway Tunnels

Steve F45 wrote:may sound dumb, but had any tbm construction been started for njt's cancelled tunnels? I mean it was cancelled when they were already working on building the overpass for 1&9 and work on the cliff face was probably a year out. I'd imagine a tbm takes several years to design and build so one should've been in the works already. If so, could amtrak resurrect that design?

Also not sure if it was asked, but whenever the new tunnels are finished. Are the 2 current tunnels going to be capped and closed off forever or completely rebuilt? I ask cause NJT wanted there tunnels to add capacity to NY by having 4 tunnels. If the 2 current tunnels are so far beyond repair then when the 2 new tunnels are completed, everyone will be basically right back at square one with only 2 tunnels going into NY.

Many years will have passed from the time ARC was cancelled to when tunnel boring would begin for the new tunnels even under the optimistic projections. Why use what by then might be an obsolete design for TBMs? When the project is ready to proceed on digging out the new tunnels, order modern TBMs designed for the soil conditions to be encountered.

The goal is to have 4 tunnels for 4 tracks between NJ and NYP. The problem with the current tunnels that Boardman is referring is that they are deteriorating and Amtrak is facing the prospect of eventually having to take one out of service for an extended period to rebuild the tunnel. A 1 track operation under the Hudson for a year would create a rather serious bottleneck. The concept is to build the 2 new tunnels which will then allow the old tunnels to be taken out of service to be rebuilt one at a time with new flood protection barriers. They would have 3 tunnel operations while each of the old tunnels are rebuilt.

afiggatt wrote:...A 1 track operation under the Hudson for a year would create a rather serious bottleneck...

A one-track tunnel route into NYP from New Jersey would be a disaster of Biblical proportions!

Steve F45 wrote:may sound dumb, but had any tbm construction been started for njt's cancelled tunnels? I mean it was cancelled when they were already working on building the overpass for 1&9 and work on the cliff face was probably a year out. I'd imagine a tbm takes several years to design and build so one should've been in the works already. If so, could amtrak resurrect that design?

When the project was cancelled by Christie in October 2010, a high-performance 8.38m diameter Robbins Main Beam TBM was being designed, with a delivery date of June 2011.

Not sure how much of the TBM work Amtrak can use though.....

I hear Seattle has a slightly used TBM that might be available.

Or just take the one from East Side Access turn right and drive under the river. In one move you've got access to Grand Central and a new tunnel under the Hudson.

Simple.

bleet wrote:I hear Seattle has a slightly used TBM that might be available.

Or just take the one from East Side Access turn right and drive under the river. In one move you've got access to Grand Central and a new tunnel under the Hudson.

Simple.

Except you'd run the risk of breaching Water Tunnel 1, thus a) cutting off drinking water to a few million people and b) flooding Grand Central with millions of gallons of water from the Delaware, Catskill, and New Croton Aqueducts, since it's likely the sluice gates at the Hillview Reservoir can't be closed as they haven't been touched since 1917.

There's a *lot* of stuff underground in Manhattan: tunnels of two different subway systems, water tunnels, sewers, steam tunnels, gas mains, etc. That's why they've never tried-- and likely *will* never try-- to build a direct rail link between GCT and Penn.

Don31 wrote:

Steve F45 wrote:may sound dumb, but had any tbm construction been started for njt's cancelled tunnels? I mean it was cancelled when they were already working on building the overpass for 1&9 and work on the cliff face was probably a year out. I'd imagine a tbm takes several years to design and build so one should've been in the works already. If so, could amtrak resurrect that design?

When the project was cancelled by Christie in October 2010, a high-performance 8.38m diameter Robbins Main Beam TBM was being designed, with a delivery date of June 2011.

Not sure how much of the TBM work Amtrak can use though.....

bleet wrote:I hear Seattle has a slightly used TBM that might be available.

Or just take the one from East Side Access turn right and drive under the river. In one move you've got access to Grand Central and a new tunnel under the Hudson.

Simple.

Suppose that a TBM is necessary for part of the Manhattan segment.

How shallow (close to street/surface level), can the TBM be used/bore?

Shallow TBM drives will not be an issue. They have to pass under the river and come up in a reasonable grade for the trains. In theory, the diameter of the NJ tunnel machine that was on order should work for Gateway, but knowing the way railroads work, Amtrak will have a ridiculous requirement for 4 more inches.

The ESA machines are too small for rail with catenary.

jlr3266 wrote:Shallow TBM drives will not be an issue. They have to pass under the river and come up in a reasonable grade for the trains.

I was wondering about the segment under 12th Avenue and perhaps under 30th street in Manhattan.

I've been told in the past that there is space for a rail tunnel to be built under NYC to access Penn Station; Water Tunnel #1 and everything mapped can be avoided; however, there is apparently some unmapped stuff that might be a problem.

Thomas wrote:
Suppose that a TBM is necessary for part of the Manhattan segment.

How shallow (close to street/surface level), can the TBM be used/bore?

There is no blanket answer to that. It depends on lots of things - geology, soil (grain size distribution), the types of structures located on the ground surface, the presence or likely presence of unknown objects in the ground, depth of the water table and, probably most importantly, the clients tolerance for risk. In many cases cut-and-cover makes more sense.....

Don31 wrote:

Thomas wrote:
Suppose that a TBM is necessary for part of the Manhattan segment.

How shallow (close to street/surface level), can the TBM be used/bore?

There is no blanket answer to that. It depends on lots of things - geology, soil (grain size distribution), the types of structures located on the ground surface, the presence or likely presence of unknown objects in the ground, depth of the water table and, probably most importantly, the clients tolerance for risk. In many cases cut-and-cover makes more sense.....

Even using cut-and-cover underneath 12th Avenue to get from the Bulkhead to the Tunnel Box Extension?

Thomas wrote:

Don31 wrote:

Thomas wrote:
Suppose that a TBM is necessary for part of the Manhattan segment.

How shallow (close to street/surface level), can the TBM be used/bore?

There is no blanket answer to that. It depends on lots of things - geology, soil (grain size distribution), the types of structures located on the ground surface, the presence or likely presence of unknown objects in the ground, depth of the water table and, probably most importantly, the clients tolerance for risk. In many cases cut-and-cover makes more sense.....

Even using cut-and-cover underneath 12th Avenue to get from the Bulkhead to the Tunnel Box Extension?

Yes, probably so. The extraction point for the TBM would be in the SE quadrant of 12th Ave and W. 30th Street, approximately 300 feet from the end of the concrete casing (don't call it a "tunnel box").

Don31 wrote:Yes, probably so. The extraction point for the TBM would be in the SE quadrant of 12th Ave and W. 30th Street, approximately 300 feet from the end of the concrete casing (don't call it a "tunnel box").

Then what would be the construction method in the 300 foot distance from the extraction point of the TBM in the SE quadrant of 12th Ave and W. 30th Street to the end of the concrete casing?

Thomas wrote:

Don31 wrote:Yes, probably so. The extraction point for the TBM would be in the SE quadrant of 12th Ave and W. 30th Street, approximately 300 feet from the end of the concrete casing (don't call it a "tunnel box").

Then what would be the construction method in the 300 foot distance from the extraction point of the TBM in the SE quadrant of 12th Ave and W. 30th Street to the end of the concrete casing?

Cut-and-cover

Don31 wrote:Cut-and-cover

Thus, there should not be too much disturbance to 12th Avenue (such as lane closings , etc)?

Also, how sure are you that there will not or will be any tunnel boring under 30th Street, to connect to a proposed future extension east, since Amtrak has claimed that they are looking into designing the Gateway Project to enable an extension to the East Side/Queens?