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Power Out on Bridges?


Smoot178

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I am curious as to why the A/C and half the lights go out while going over some bridges along the NJCL route. I know that there is some sort of revolving bridge right before the Amboys heading to NYC and that it happens there.

 

Why does this happen?

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I am curious as to why the A/C and half the lights go out while going over some bridges along the NJCL route. I know that there is some sort of revolving bridge right before the Amboys heading to NYC and that it happens there.

 

Why does this happen?

 

I think you are referring to the place where the NJCL changes from 12.5Kv to 25Kv. Basically what happens is that the pantograph drops from the catenary on the neutral section and then goes back on after reaching the 25 Kv section. The A/C goes off in the process along with the main lights, but the auxillary lights go on since the train is running on it's own spare "battery."

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There are 3 are phase gaps on the NJCL Morgan draw,Laurel(Hazlet/Holmdel) and east of Bergen Place in Red Bank. Lights go out in all cars but the ML's. R44 is correct about the voltage change.

 

How does the MLVs still have their power? I thought the locomotive switches to "battery/emergency" mode as soon as power is lost, justifying that the cars wouldn't receive any power.

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The ML's were built so that when they go through a phase gap the lights stay on..this is accomplished through a battery which goes on as soon as the train sets the pan down for the phase gap,the battery only lasts so long though. So if the train was to lose the pan well they would have lights for a while but then they would go off.

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They have big beefy batteries, i believe they have 2 per car. I've never seen a MLV "flick" however the lights go a TAD bit dimmer where the phase gaps are. On an EMU set the breaks are very pronounced, and sometimes they don't come back on for up to a minute or 2. I believe this is when one of the married pairs has a single unit in between*, but i'm not 100% sure.

 

It seems to be getting worse and worse as they approach EOL, but new equipment is on the horizon.

 

*A-B A B-A

 

- (A)

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Speaking of Arrows

 

They can only work through phase gaps where the power remains the same voltage such as Morgan on the NJCL. There is no way to change the voltage of an Arrow III without shopping it, this will be corrected with the much anticipated Arrow IV when ever its built.

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Speaking of Arrows

 

They can only work through phase gaps where the power remains the same voltage such as Morgan on the NJCL. There is no way to change the voltage of an Arrow III without shopping it, this will be corrected with the much anticipated Arrow IV when ever its built.

 

:tup:

 

- A

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One electrical transmission wire (metal line single conductor) can carry one phase out of 3 phases generally produced by power plants (some plants are specifically tasked & only produce 1 or 2 phases but this is not the kind connected to the national grid). You can't connect 2 different phases or you short the circuit & create a breaker trip & resulting blackout on those circuits shorted. Phase break basically allows the catenary to continue all most completely physically uninterrupted, letting the line be divided into segments which can be powered only when a train is under it collecting current, and in emergency the loss of one of the segments does not shut down the entire track from end to end that has that wire over it.

 

Think of it like a series of metal wire hangars lined up lengthwise and run your finger across it. Finger being the pantograph.

 

The gaps are usually visually identified by a device called a side or slider. The pantograph slides across this non-conductive device from one contact wire to another. Typically the slider is located on a short neutral section of wire to ensure no arcing takes place between the 2 contact wires.

 

Hope that helps! :P

 

- A

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Having stopped within view of the sliders 10 times in the last year i could go into detail about how they look and stuff too. I believe i have a few photos too, if i have not deleted them for blurryness. :cool:

 

- A

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Oh and amtrak upgraded the sliders for the acela on the 2 inner express tracks on the NEC, so they are a bit more refined looking. Also of note is the number of phase gaps & sliders between trenton & hamilton on track 3 and 4. I believe they do this in case a segment goes out the next train can go around it to get to the station.

 

- A

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