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Signal question
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icsd701000
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Posts: 110
Signal question
 
« on: May 14th, 2008, 5:32am »
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I have a question regarding Signals at a interlocker. This is the UP and CNIC Diamond at Sullivan, IL. Both Lines have Signal poles with the standard 3 lights on top. The UP has another set below them of 3 and the IC has another set below theres but they are a 2 signal set. My question is the bottom sets area always red no matter what. I have seen hundreds of trains go through this diamond and only the top set of lights change. What is the purpose of the bottom set of light?

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limejuice
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Re: Signal question
 
« Reply #1 on: May 14th, 2008, 12:02pm »
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on May 14th, 2008, 5:32am, icsd701000 wrote:       (Click here for original message)
I have a question regarding Signals at a interlocker. This is the UP and CNIC Diamond at Sullivan, IL. Both Lines have Signal poles with the standard 3 lights on top. The UP has another set below them of 3 and the IC has another set below theres but they are a 2 signal set. My question is the bottom sets area always red no matter what. I have seen hundreds of trains go through this diamond and only the top set of lights change. What is the purpose of the bottom set of light?

 
While I'm in NORAC land, I think I can answer your questions. On the UP, it sounds like they have 4 block signaling in effect there, which provides an aspect of yellow over green (Approach Medium) in advance of a yellow or yellow over red aspect. (Approach) Because this is an interlocking, a red over yellow aspect (Restricting) may be displayed in the event that a track circuit has failed, or other equipment is standing within interlocking limits. This is what is referred to as a "call-on". It's like a "manual override". That red over yellow aspect will explain the 2-aspect bottom head on the IC, which probably displays yellow or red.


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k5sss
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Posts: 193
Re: Signal question
 
« Reply #2 on: May 24th, 2008, 1:15am »
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on May 14th, 2008, 5:32am, icsd701000 wrote:       (Click here for original message)
My question is the bottom sets area always red no matter what. I have seen hundreds of trains go through this diamond and only the top set of lights change. What is the purpose of the bottom set of light?

On UP, a red on the lower head is always interpreted the same as if there were no lower head at all, IIRC.  However, there are some indications that require a second head.  For instance, UP and CNIC may not currently exchange traffic there so all trains are straight through -- but if that changed, they'd need the second head to indicate a diverging route.  There are a few other miscellaneous indications that also require a second head, though they tend to be rare and probably only happen when you're not looking


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streamline_j3
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Posts: 84
Re: Signal question
 
« Reply #3 on: May 26th, 2008, 9:39am »
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  Hereis another signel question .
   I was crossing the two track main on the New York state csx line and saw a single flashing red light on the signal tower that has four lights on it two for eastbound and two for westbound traffic.
  I was wondering what the single red flashing signai means.
  Will check my printed copy of signal asspects Igot from the NORAC site.


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k5sss
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Re: Signal question
 
« Reply #4 on: Jun 5th, 2008, 1:38pm »
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I don't see flashing red in the list of CSX signal aspects, but some other RRs often use flashing red to mean the same as a solid lunar white, i.e. Restricting.  Would that have made sense in the scenario you saw?

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