Amtrak Gateway Tunnels

Is this the profile of the tunnels as built?

http://www.gutenberg.org/files/18229/18 ... plate1.png" onclick="window.open(this.href);return false;

Thomas wrote:That link says eighty feet (instead of 90 feet)...

Yes you're right. However, it also says the tunnels were located thirty-five feet under the river bed but the river depth -- as per the nautical chart -- varies from forty-five feet to fifty-four. That's why I wrote ninety feet. I guess if the tunnel track is level (I'm not sure it is but I don't really know) then in spots the tunnel might not be as deep under the river bottom as thirty-five feet.

I tried to look at the tunnel profile but the link isn't opening for me.

Cripes, I can't figure out how to link to it , nor can i find the image again . Perhaps someone else can , its a great picture.

Tommy Meehan wrote:Yes you're right. However, it also says the tunnels were located thirty-five feet under the river bed but the river depth -- as per the nautical chart -- varies from forty-five feet to fifty-four. That's why I wrote ninety feet. I guess if the tunnel track is level (I'm not sure it is but I don't really know) then in spots the tunnel might not be as deep under the river bottom as thirty-five feet.

I wonder what the maximum depth of the Gateway Tunnels will be...

Also, regarding the Tunnel Box, how much higher above the bottom of the 25 foot Tunnel Box will the tracks be (five feet, or will the tracks be right at the bottom, etc)?

Thomas wrote:

Tommy Meehan wrote:Yes you're right. However, it also says the tunnels were located thirty-five feet under the river bed but the river depth -- as per the nautical chart -- varies from forty-five feet to fifty-four. That's why I wrote ninety feet. I guess if the tunnel track is level (I'm not sure it is but I don't really know) then in spots the tunnel might not be as deep under the river bottom as thirty-five feet.

I wonder what the maximum depth of the Gateway Tunnels will be...

Also, regarding the Tunnel Box, how much higher above the bottom of the 25 foot Tunnel Box will the tracks be (five feet, or will the tracks be right at the bottom, etc)?

Not much more than the current tunnels given the grade involved in getting from the under the bottom of the river up to the surface at 9th Avenue.

With modern technologies, they may simply freeze all the soil and dig it out that way. Then by the bulkhead inject large amounts of grout to seal it all up from the porous rip-rap layer and simply dig through it. So, you may end up with a tunnel closer to the river bottom vs the existing tunnels...?

Why isn't Amtrak's Tunnel Box being connected to Penn Station's Throat soon?

Thomas wrote:Why isn't Amtrak's Tunnel Box being connected to Penn Station's Throat soon?

No need to. The tunnel box serves only one purpose right now: To make sure the buildings can be built without obstructing things in the future.

We are probably 6-7 years away from anything being done with the space saver. The bit in manhattan will likely be constructed before the actual new tunnels, because they plan to connect to the existing tracks. It is also easier to build on land vs under a river. This means the penn station south tracks will be useable before the tunnels. Then i'm guessing the tunnels will be completed & operational 10-15 years from now.

My guess is that by 2028 gateway will be complete or nearing completion.

25Hz wrote: My guess is that by 2028 gateway will be complete or nearing completion.

Or the politicians will still be talking about it and Thomas will still be asking questions.

25Hz wrote:We are probably 6-7 years away from anything being done with the space saver. The bit in manhattan will likely be constructed before the actual new tunnels, because they plan to connect to the existing tracks. It is also easier to build on land vs under a river. This means the penn station south tracks will be useable before the tunnels. Then i'm guessing the tunnels will be completed & operational 10-15 years from now.

My guess is that by 2028 gateway will be complete or nearing completion.

1. When do you see real Gateway work (other than the Tunnel Boxes) beginning construction?

2. Are you 100% sure that the Penn Station South Tracks Upper Level will get built?

25Hz wrote:With modern technologies, they may simply freeze all the soil and dig it out that way. Then by the bulkhead inject large amounts of grout to seal it all up from the porous rip-rap layer and simply dig through it. So, you may end up with a tunnel closer to the river bottom vs the existing tunnels...?

They did freezing in Boston's Fort Point Channel to get through soft mud and under? a subway tunnel. It was a disaster; there was a collapse, flooding, destroyed equipment and fortunately no loss of life. The Ted Williams Tunnel by contrast was built in segments in a shipyard, floated, sunk, then joined and lined with cement. This was the only part of the project that was done on-time and on budget.

If the tunnel is too shallow, it could be damaged by ships or shifting sediments. If it is too deep, the approaches will be difficult to design.

BandA wrote:

25Hz wrote:With modern technologies, they may simply freeze all the soil and dig it out that way. Then by the bulkhead inject large amounts of grout to seal it all up from the porous rip-rap layer and simply dig through it. So, you may end up with a tunnel closer to the river bottom vs the existing tunnels...?

They did freezing in Boston's Fort Point Channel to get through soft mud and under? a subway tunnel. It was a disaster; there was a collapse, flooding, destroyed equipment and fortunately no loss of life. The Ted Williams Tunnel by contrast was built in segments in a shipyard, floated, sunk, then joined and lined with cement. This was the only part of the project that was done on-time and on budget.

If the tunnel is too shallow, it could be damaged by ships or shifting sediments. If it is too deep, the approaches will be difficult to design.

Pretty certain that submersed tube would not work in the hudson. It worked in the east river because roosevelt island is there and the channels on either side are not that wide.

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I'm sure there are numerous other issues that make TBM more feasible.

BandA wrote:...They did freezing in Boston's Fort Point Channel to get through soft mud and under? a subway tunnel...If the tunnel is too shallow, it could be damaged by ships or shifting sediments. If it is too deep, the approaches will be difficult to design.

I'm not sure that Ft. Point Channel -- whatever they did -- is applicable to the Hudson River. About the only thing they have in common is water. Considering factors such as width, depth, the tidal action, the sheer volume of water in the Hudson, they are very different. I'm sure the tunnel will be buried in the river bed, well under the level where it could be struck by passing ships. One hundred years ago the Pennsylvania Railroad did have some concerns that a ship dropping an anchor directly on top of their tunnel might potentially pose some risk. However, being that the tunnels seem to be at all points at least twenty-five deep in the river bottom I don't think this was ever a problem.

Don't forget, the Hudson is a navigable river and thus under the control of the U.S. Coast Guard. So however Amtrak decides to build it's tunnels -- and there is no plan yet that I'm aware of (an EIS doesn't even have funding yet) -- the USCG will have to approve it before they can start building. In fact there are probably a number of federal and state agencies that will have oversight as well.

Ridgefielder wrote:I'm sure it's technically possible. However, aren't the sediments in the North River contaminated w. PCB's and other nastiness? Not sure the EPA/Army Corps/whomever would bless a dredging project of this magnitude if it involved stirring up contamination from the riverbed muck.

Apparently the US EPA and the Corps of Army Engineers have already ruled out this method of tunnel construction in the Hudson for the reasons Ridgefielder mentions: the amount of environmentally hazardous material buried in the river bed. I believe it will have to be a bored tunnel. Just to add, I think this information came from a Parsons Brinckerhoff engineer speaking at a symposium that was held last year. There is nothing printed or on line that I know of so I can't post a link. But I think dredging a bed for the tunnel has been ruled out.

Tommy Meehan wrote:(an EIS doesn't even have funding yet)

As far as I am concerned, Amtrak is planning to begin the EIS and engineering for the new tunnels this year. In fact, in the link below, it states "Gateway Program Development Study (26 mos.): Starting in May 2014, this study will focus on development of overall Program delivery and management, including implementation strategies partnerships, funding and financing, schedule, and risks" http://www.amtrak.com/ccurl/458/748/FY1 ... l-Plan.pdf" onclick="window.open(this.href);return false;

(on page 150)/

Program management, according to Amtrak's FY 2014 Budget Justification, "refers to development of a contract packaging approach and issuing the first design and environmental review package for the proposed tunnels within FY2014." (http://www.amtrak.com/ccurl/851/32/Amtr ... tion,0.pdf" onclick="window.open(this.href);return false; on page 34).

Thus, one can infer that the Hudson tunnel's EIS and engineering should have begun recently...