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Signal Change

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  • Member since
    January 2010
  • From: Omaha, Nebraska, USA
  • 40 posts
Posted by Jovet on Sunday, May 3, 2020 11:50 AM

jeffhergert
Speed also plays a part in how fast the signals seem to drop to red.  The detection point is the same, but the faster the train the more of it gets past the signal before it changes.

Yep.  The time is the same, and represets the time it takes for the signal logic (relay or otherwise) to register the occupation of the track, update surrounding signals, and possibly communicate it to the dispatcher display.  There is also a small delay usually designed in to prevent momentary false detections from wreaking havoc.  All of this will vary by installation and individual signal, but it will be a pretty consistent amount of time for the same signal, regardless of the train speed.

MidlandMike
My understanding is that a hi-rail vehicle would not be detected by a signal circut.  How would a hi-rail know if it was safe to pass a signal if it would not (approach) light?


The Hy-rail vehicles I have seen have insulated axles, but also have metal brush pick-ups which can shunt the track circuits at the option of the driver via a switch on the dash. 

To add to what BaltACD stated: Hy-rail vehicles are generally expected to behave as any train would.  They cannot exceed the track speed limit, are required to obey Stop signals, etc.

JPS1
You got it.  Thanks for the explanation.

Good, I'm happy to help.  If you have any other questions, feel free to ask.  Someone can try to answer them.  None of us knows everything, but 40 heads are usually better than one.

  • Member since
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  • From: US
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Posted by BaltACD on Sunday, May 3, 2020 7:37 PM

Jovet
To add to what BaltACD stated: Hy-rail vehicles are generally expected to behave as any train would.  They cannot exceed the track speed limit, are required to obey Stop signals, etc.

Hi-rail vehicles do not operate on any form of signal indication.  They operate on their Track Car Authorities only.  If they have a authority through a Control Point, their only obligation is to see that the route that is lined is the one that their authority authorizes. In the CSX CADS the dispatcher must line the switches for the route through a Control Point if the authority is issued through and beyond a Control Point before the authority is issued. 

Maximum speed for a hi-rail on CSX is 40 MPH - I have seen photographs of what happens when higher speeds are attempted on curves - it isn't pretty.

Never too old to have a happy childhood!

              

  • Member since
    December 2001
  • From: Northern New York
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Posted by tree68 on Sunday, May 3, 2020 7:40 PM

BaltACD
Maximum speed for a hi-rail on CSX is 40 MPH - I have seen photographs of what happens when higher speeds are attempted on curves - it isn't pretty.

We won't discuss switches...

I've never dumped a hirail on a switch, but I've seen it done.

LarryWhistling
Resident Microferroequinologist (at least at my house) 
Everyone goes home; Safety begins with you
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There's one thing about humility - the moment you think you've got it, you've lost it...

  • Member since
    May 2003
  • From: US
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Posted by BaltACD on Sunday, May 3, 2020 9:39 PM

tree68
 
BaltACD
Maximum speed for a hi-rail on CSX is 40 MPH - I have seen photographs of what happens when higher speeds are attempted on curves - it isn't pretty. 

We won't discuss switches...

I've never dumped a hirail on a switch, but I've seen it done.

 

Excess speed on a curve

Never too old to have a happy childhood!

              

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