Gateway Project/New York Penn Station capacity improvement

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jis said:
Sometimes they abandon them underground, but more often they disassemble them and retrieve them for use elsewhere.

For example in the boring of the East-West Green Line of the Kolkata Metro, they retrieved most boring machines and some were redeployed elsewhere in the project.

One was a particularly strange case. Between Esplanade and Sealdah at a place called Bowbazar, an area occupied by many over 100 years old ramshackle buildings, one of the boring machines struck a massive aquifer, which drained into the bored tunnel until they managed to seal it behind the boring machine. But enough water pored into the tunnels to cause subsidence above which brought down about a dozen buildings over a period of time. All the residents were rescued and housed in temporary housing while they started cleaning up the mess underground. Eventually they dug down a shaft from above and retrieved the entire boring machine, and deployed another one from the other end to dig to the shaft. It took two years to rescue the tunnel which was completed recently. Ironically, the original plan was to place the tunnel under a road on the surface, but the local residents for whatever reason rose up in arms and prevented that and forced it to be routed under a residential area, which of course finally all collapsed into the subsidence. People need to think hard about what they are doing before forcing technically unsound courses upon projects as such can come back to bite one in their own rear ends.

You can see the block that was wiped out by subsidence and is now occupied by the rescue shaft which is about to be filled in after the tunnel underneath is completed and the second boring machine coming in from the other end is disassembled and pulled out through the shaft. It is the empty block marked "Metro Work in Progress (Green Line)":

https://www.google.com/maps/place/Bowbazar,+Kolkata,+West+Bengal,+India/@22.568256,88.3617903,173m/data=!3m1!1e3!4m6!3m5!1s0x3a0277abc30987bb:0xea24dd255f2b25b2!8m2!3d22.5668237!4d88.3614764!16s/m/02z9k9x?entry=ttu

Hopefully nothing like this will come to pass in digging the new tunnels in New York. Incidentally while digging the original tunnel;s there were a case of a blowout or two when the roof of the tunnel gave way, but each was sealed and the project rescued. The new tunnel ceilings are much deeper down from the river bed than the original tunnels. That is why the big curve was required to give more liner space to hold the gradients within limits.
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Fascinating - Kolkata looks so intriguing. Must get off my duff and go.
 
This tunnel boring machine ran into a ten-foot anchor last year: https://www.cbbt.com/news/project-connect-spring-2024/ It took 10 months to fix the machine, which will delay the Chesapeake Bay Bridge Tunnel project about eight months. The pictures are worth a look if you are interested in tunnel boring machines. "Anchor's away" as the Va. Pilot put it: https://www.pilotonline.com/2024/05...tunnel-after-old-ship-anchor-delayed-project/

Beachcombers with their metal detectors must have some feelings about this "find."
 
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west point said:
Actually, since higher voltage conductors are going to be on some poles the work probably did not have any choices?? If your pay attention of the present track it appears that poles are much farther apart.
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I don't think the pole distances have anything to do with what sort of catenary will be installed. It has more to do with the need to place the poles on the pillars that support the bridge. This is done quite often in India too.
 
jis said:
An interesting article about how the arches of the bridge are being manufactured and how they will be brought to site on barges and installed

https://www.northjersey.com/story/n...-arches-barged-down-hudson-river/74999418007/
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This method is a repeat of the work when the 3 spans of the RR bridge was replaced over the Mississippi river at St. Louis. The engineering videos of the three spans being replaced at St louis were very informative. Hoping there will be a similar video for Portal North. Having to maneuver the new span past the Amtrak swing bridge may take careful work by a few tug boats. Tell the contractor -Please Please do not hit the swing bridge.
 
Just a quick question about capacity at Penn and this project—when they claim 48 trains per hour, does that mean 24 in each direction? Or 48 in each direction (ie 96 total)? I know the current tunnels claim 24 per hour in “bidirectional capacity” and I thought that meant 12 through each tunnel (12 inbound, 12 outbound per hour etc), but am I mistaken or what exactly is the true capacity right now and what will it be once these new tubes are complete?

I ask because I noticed that between 5:00pm and 5:59pm during the week, there are 19 scheduled trains (16 NJT, 3 Amtrak) that use the tunnels. That’s not even including the Amtrak trains using the empire connection which there is atleast 1 during that window. That’s seems to be comfortably over the 12 train max (if that is the max) but also notably below the 24 train max (if that is the max) during the busiest time of day.
 
They mean 48 in peak direction, with 2 tubes each way. That is a stretch, unless they rebuild the signal system. A slot is basically 3 minutes, so 20 TPH.

BUT, there is no place to put those trains other than Penn Station South, and head back to Jersey, like to a new Boonton Yard, equivalent to Midday Storage Yard the LIRR has in LIC, north of Sunnyside Yard for Grand Central Madison trains.

Thru running fans want to retain the 1910 NYPS footprint for all eternity, rip out some station tracks, widen the platforms, to throw them over the wall to the LIRR to deal with, don't bother them with the sordid details. When pigs fly. LIRR main line east of Harold is 3+1 peak direction and that interlocking is the most congested in the continent as it is. They don't understand that.
 
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It is 24tph through each Hudson tube. But simultaneous operation of both tunnels at full capacity far overloads A interlocking at the NYP end. So effectively it is close to 24tph in the rush direction and maybe 6-8 in the opposite direction in reality.

The East River tunnels are more fluid and again theoretically 24 in each but in reality it is something less. I am not sure what the latest actual numbers are.
 
jis said:
It is 24tph through each Hudson tube. But simultaneous operation of both tunnels at full capacity far overloads A interlocking at the NYP end. So effectively it is close to 24tph in the rush direction and maybe 6-8 in the opposite direction in reality.

The East River tunnels are more fluid and again theoretically 24 in each but in reality it is something less. I am not sure what the latest actual numbers are.
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Got it thank you, but is there a reason why they would only schedule 19 trains total during the peak of rush hour? Seems like they are leaving excess capacity there if so, which is very surprising.

Lastly, are the plans to improve A interlocking capacity set along with this gateway tunnel, or is there an ongoing battle with that?
 
It is likely because they can only get 19 reliably through A interlocking which is the limiting bottleneck. The tunnels are not the limiting bottleneck. Once the trains arrive at the NY end space has to be found for them on platforms and routes have to be found from the tunnel track to the platform. It is a complex choreography that is beyond simple minded but learned sounding analysis we are so prone to here among us.

The actual scheduling is done based on simulations to establish practical viability. NY Penn Station is highly non trivial to dispatch. The stated maximum throughput is based on completely perfect execution of the choreography, which of course in reality seldom happens.
 
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jis said:
It is likely because they can only get 19 reliably through A interlocking which is the limiting bottleneck. The tunnels are not the limiting bottleneck. Once the trains arrive at the NY end space has to be found for them on platforms and routes have to be found from the tunnel track to the platform. It is a complex choreography that is beyond simple minded but learned sounding analysis we are sonprone to here among us.
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Makes me wonder why we are building 2 more tubes if they really aren’t the bottle neck. Is there an agreed upon plan for solving A interlocking?
 
Touchdowntom9 said:
Makes me wonder why we are building 2 more tubes if they really aren’t the bottle neck. Is there an agreed upon plan for solving A interlocking?
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The existing tunnels have serious structural issues. Do you propose they wait until one or both collapse or flood before starting this process?

They could in theory totally shut down one tunnel, rehab it, reopen it and do the same for the other tunnel. Running two directions in a single tunnel would cut the capacity by more than 50%. Whenever they reverse the direction of the tunnel, they would have to wait for any trains already in the tunnel to clear the interlocking after the end of the tunnel before switching the interlockings to the tracks at either end to the main lines in the other direction. This takes whatever time it takes for the a train to completely traverse the tunnel and both interlockings before they could switch it. With single direction running, they only have to separate the trains by their braking distance, which is less than the length of the tunnel.

One tube doesn't have half the capacity of two tubes. It has much less than half the capacity.

I don't know what the rehab plan is after the new tunnels open. They could shut down both and rehab them simultaneously, or they could shut down the tunnel which is in worse shape, and use the other to increase capacity by 25 to 30% (not 50% because the tunnel would have to switch directions occasionally) during the rehab, then do the same on the other tunnel. This would take longer to finish but would provide some capacity increase immediately.
 
Touchdowntom9 said:
Makes me wonder why we are building 2 more tubes if they really aren’t the bottle neck. Is there an agreed upon plan for solving A interlocking?
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The existing tunnels need work that can only be done by shutting them down. They got flooded badly with Sandy and thats kicked off a whole host of problems.
 
Touchdowntom9 said:
Makes me wonder why we are building 2 more tubes if they really aren’t the bottle neck. Is there an agreed upon plan for solving A interlocking?
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If they build Penn Station South, there is no issue. Most trains in the new tunnels will use it.

On weekends, trains are scheduled to use only one tube - which means 8 slots per hour, allotted 5 to NJT, 3 to Amtrak. They currently run 19TPH rush hours, which would be a 58% reduction in capacity.

If the NIMBYs, disguised as a thru-running plan, win, there is no increase in capacity. They whine about this $17 Billion , but not about the new PABT 8 blocks up that will cost $15 Billion.

The concept of new tunnels, such as with ARC, was conceived long before Sandy happened.
 
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Amtrak25 said:
If they build Penn Station South, there is no issue. Most trains in the new tunnels will use it.

On weekends, trains are scheduled to use only one tube - which means 8 slots per hour, allotted 5 to NJT, 3 to Amtrak. They currently run 19TPH rush hours, which would be a 58% reduction in capacity.

If the NIMBYs, disguised as a thru-running plan, win, there is no increase in capacity. They whine about this $17 Billion , but not about the new PABT 8 blocks up that will cost $15 Billion.

The concept of new tunnels, such as with ARC, was conceived long before Sandy happened.
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You are absolutely correct. the new tubes together with Penn South is planned based on primary flow from the new tubes to Penn South and the current tunnels primarily feeding the current Penn track except 1-4. This additionally removes the most serious congestion causing traffic between tracks 1-4 and the current tunnels at A interlocking, by removing those trains from current A interlocking into the new tunnels. This makes A interlocking more fluid with huge reduction of conflicting traffic
 
Touchdowntom9 said:
Just a quick question about capacity at Penn and this project—when they claim 48 trains per hour, does that mean 24 in each direction? Or 48 in each direction (ie 96 total)? I know the current tunnels claim 24 per hour in “bidirectional capacity” and I thought that meant 12 through each tunnel (12 inbound, 12 outbound per hour etc), but am I mistaken or what exactly is the true capacity right now and what will it be once these new tubes are complete?

I ask because I noticed that between 5:00pm and 5:59pm during the week, there are 19 scheduled trains (16 NJT, 3 Amtrak) that use the tunnels. That’s not even including the Amtrak trains using the empire connection which there is atleast 1 during that window. That’s seems to be comfortably over the 12 train max (if that is the max) but also notably below the 24 train max (if that is the max) during the busiest time of day.
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I looked at the NJT employee timetable. I used Bergen interlocking as the measuring point for no particular reason.

Westbound 5PM - 5:59PM @ Bergen
A2167, 3363, 3949, 3511, 3725, A653, 3951, 6647, 6431, 3265, 3867**, A193, 3513, 6273, 6651, 3267, 3953, 3727, 3871, 6653

** Does not operate getaway days

Eastbound 5PM - 5:59PM @ Bergen
X880*, 6248, A94, 3260, 6658, 3860, 3896, X662*, 3510, A2170, X826*, X882*, X630, 6252, A20, 3736, 3862

* Getaway days only (2024: May 24, July 3, August 30, November 27, December 24)

Westbound: 20 / 19 on getaway days
Eastbound: 13 / 17 on getaway days


It looks like they don't fully utilize eastbound capacity as 4 extra trains are scheduled on getaway days.

None of this includes the constraints of "the ladder" which would eventually cause the breakdown of the linear relationship between tunnel capacity and station movement capacity, as alluded in other posts. The breakdown may already be happening in the dense rush hour schedule periods.

Gateway will tie into the A yard (tracks ending in "A") next to the Empire Connection. Movements on tracks 1-4 (and maybe more) will be possible without blocking other tracks. Also, Empire Service trains usually land on 5 or 6 so they will only block 1-6 when moving.

Existing track layout and future track layout attached. Sources:
https://media.amtrak.com/wp-content/uploads/2017/06/NYP_Track-Map_WORK.jpg
https://rpa-org.imgix.net/work/Repo...io=&w=2700&s=7d8b042654e0aad1a57fc5b02ebace8b
 

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