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nostalgia

How can Amtrak operate into Grand Central?

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Last Friday, March 24, Amtrak and a NJT trains sideswiped each other at Penn Station on Track 6. This track leads to the Empire Division to Albany. Amtrak turned trains at Croton Harmon. However, I saw a video on another site of an Amtrak train at Grand Central.

 

I'm confused. I get to the two mixed up but I thought Amtrak and the LIRR used over running of the third rail and Metro North used under running. If this is true, how could Amtrak diesels operate in Grand Central, assuming electric power was used like MN trains.

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Pretty sure Amtrak has locomotives that could run both underrunning or overrunning third rail shoes. I think Amtrak set it as overrunning the day of the NJT incident because Penn use overrunning while GCT use underrunning. If there is advance notice Amtrak may be able to change it.

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Pretty sure Amtrak has locomotives that could run both underrunning or overrunning third rail shoes. I think Amtrak set it as overrunning the day of the NJT incident because Penn use overrunning while GCT use underrunning. If there is advance notice Amtrak may be able to change it.

 

^This here is the correct answer.

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if i am not mistaken Electric Power was used

 

I'm trying again. Amtrak and Metro North DON'T access electricity the same way. I've read that the third rail pickup on their diesels aren't in the position. One runs above the third rail and the other runs below the third rail.

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One train ran all the way to GCT and returned north in service. 

 

 

Pretty sure Amtrak has locomotives that could run both underrunning or overrunning third rail shoes. I think Amtrak set it as overrunning the day of the NJT incident because Penn use overrunning while GCT use underrunning. If there is advance notice Amtrak may be able to change it.

Amtrak's P32AC-DM locomotives are only compatible with LIRR-style over-running third rail. The third rail shoes fold away in order to clear MNRR's third rail.

 

In the case that OP is referring to, the train ran in and out of Grand Central on diesel power, which is allowable during "emergencies", which the derailment at Penn Station certainly qualifies as.

 

This is the train in question:

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One train ran all the way to GCT and returned north in service. 

 

 

 

Amtrak's P32AC-DM locomotives are only compatible with LIRR-style over-running third rail. The third rail shoes fold away in order to clear MNRR's third rail.

 

In the case that OP is referring to, the train ran in and out of Grand Central on diesel power, which is allowable during "emergencies", which the derailment at Penn Station certainly qualifies as.

 

This is the train in question:

http://www.youtube.com/watch?v=wl28vJAurY8

Yes, that's the video I was referring. I don't see how Metro North can run trains into Penn, notwithstanding the need to change power supply. (Amtrak motors have a switch that changes the voltage from 12.5 KV/60Hz to 12.0 KV/25Hz)

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Yes, that's the video I was referring. I don't see how Metro North can run trains into Penn, notwithstanding the need to change power supply. (Amtrak motors have a switch that changes the voltage from 12.5 KV/60Hz to 12.0 KV/25Hz)

The only things that Metro North would be able to run into Penn currently are M8 sets on the New Haven Line. I believe that the catenary is 12.5kV at 60Hz all the way down to Gate interlocking in Queens, by Sunnyside Yard. South of that it's 12.5kV at 25Hz, which the M8s can't do. The M8s have dual-position shoes that let them operate on either top-contact (LIRR) or bottom contact (MNR) third rail, which means they could stay under the wire to Sunnyside Yard and then swap to third rail between Sunnyside and Penn Station. As far as Hudson line trains go, they'd need to refit the Metro-North P32ACDMs with the M8-style dual position shoe to run them into Penn for regular service.

 

As an electrical engineering student, the question about 25Hz to 60Hz is interesting and depends on how the power electronics are set up on the M8s. If the power system rectifies everything to DC and then onboard inverters generate the waveforms to drive the motors (which I believe is what happens, because the railway supplies single-phase power and the motors are all three-phase), then adding 12.5kV 25Hz functionality to the M8 wouldn't be all that hard. My best guess is that the issue is with the initial transformer (the one that drops the 12/25kV down to several hundred or a thousand volts prior to rectifying it into DC for powertrain use.

 

The M8s' main transformers are sized for 60Hz and are therefore too small to handle 25Hz power. The higher the frequency of AC power, the smaller total amount of electromagnetic flux the transformer has to juggle between cycles. If the amount of flux per mass unit on the transformer core goes too high the core saturates and it stops functioning properly. Thus, the MTA can (and did) save weight by picking a transformer sized for 60Hz rather than 25Hz, but that limits them from operating under the wire south of Sunnyside Yard.

Edited by engineerboy6561
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given the risk that something could go wrong, I would not put it past them to equip the replacements for the P32s with multi function shoes and in the more near term they should really consider the possibility of keeping a special set of underrunning shoes that they could swap out if necessary.

 

Let's say Spuyten Duyvil bridge gets stuck, or worse, is rendered useless for a long period of time. can they live with routing trains around Mott and having to pick up and drop off an electric engine at New Rochelle? a weekend of doing that was neat. A month or more straight would be annoying.

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Isn't the East Side Access Tunnel supposed to make this easier?

 

I've heard that Amtrak is being possessive of a trackbed that would be used by the ESAT upon completion and that's why progress has stalled.

 

Sent from my m8 using Tapatalk

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Isn't the East Side Access Tunnel supposed to make this easier?

 

I've heard that Amtrak is being possessive of a trackbed that would be used by the ESAT upon completion and that's why progress has stalled.

 

Sent from my m8 using Tapatalk

 

East Side Access is for LIRR only and the 63rd Street tunnel can only fit EMUs (M3, M7 and M9).

 

Amtrak is being possessive of a portion of Harold Interlocking and doesn't really want to have to reroute trains through the interlocking, so that the ESA can be linked to the Main Line LIRR.

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East Side Access is for LIRR only and the 63rd Street tunnel can only fit EMUs (M3, M7 and M9).

 

Amtrak is being possessive of a portion of Harold Interlocking and doesn't really want to have to reroute trains through the interlocking, so that the ESA can be linked to the Main Line LIRR.

I figured as much. I hope that's covered in the potential lawsuit so progress can finally be made.

 

I find it incredibly troubling that Amtrak can be selective toward its most profitable region.

 

It makes no more business sense than a bus driver allowing free rides.

 

Remember the "urban transit with a suburban attitude" tidbit? I understand that things should be much better down here but they aren't.

 

That patience goes a long way. Perhaps better than me given the many tunnels I've found myself stuck in with riders.

 

Sent from my m8 using Tapatalk

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I figured as much. I hope that's covered in the potential lawsuit so progress can finally be made.

I find it incredibly troubling that Amtrak can be selective toward its most profitable region.

It makes no more business sense than a bus driver allowing free rides.

Remember the "urban transit with a suburban attitude" tidbit? I understand that things should be much better down here but they aren't.

That patience goes a long way. Perhaps better than me given the many tunnels I've found myself stuck in with riders.

Sent from my m8 using Tapatalk

Pretty sure EVERYTHING at Amtrak is in need of repair due to lack of funding. I find it disgraceful that OUR NATIONAL System get less operating AND capital budget than some regional operators (and it doesn't even need to be big transit operator)
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