From: 31ochs@gw.wmich.edu
Newsgroups: rec.railroad
Subject: Re: Signal type (was: Re: Semaphore Signals)
Date: 30 Aug 92 01:19:22 EST
Organization: Western Michigan University

In article <1992Aug29.042751.16448@usenet.ins.cwru.edu>, elw4@po.CWRU.Edu (Evan L. Werkema) writes:
> 
> In a previous article, CSS3@psuvm.psu.edu () says:
> 
>>   The recent discussion about semaphores and signal indications brings up a
>> point I've wondered about for years, but never asked. Why is it on some lines,
>>  mostly branch lines I've noticed, there is a semaphore signal or some other
>>  kind of signal that seems to be permanently set in the "approach" (yellow)
>>  mode not too long before an interlocking crossing with another RR. I've
>>  seen these on both Illinois Central and on a couple ex-PRR branch lines in
>>  Indiana and Illinois. I would think that having the signals protecting the
>>  crossing would be protection enough. From what I can tell, these approach
>>  signals never change indication, even when an opposing train passes by them.
>>  I belive on the ex-PRR lines there was a letter "A" on the signal masthead,
>>   which I assumed meant "approach." It would seem logical to have these
>> signals to "hold" a train away from the signal before the crossing if the
>>   crossing is located in an urban area where the railroad doesn't want a
>>   waiting train to block grade crossing. But these signals apparently do
>>not serve that function.
>>
>>    How about it signal experts, what is the purpose of these signals?
> 
>   I'm no expert, but here's what I know on the subject.  On the ATSF, those 
> are called Inoperative Approach Signals, for obvious reasons.  The system 
> standard says these signals are to be placed at interlockings where speed is 
> restricted to 20 mph and where no other approach signal is provided.  This 
> generally means branch line crossings or junctions, although a signal of this 
> type guards the southern approach to the junction at Isleta, NM, where the 
> line north from Belen meets the main line followed by the Southwest Chief.
>   Santa Fe's standard for the inoperative approach is a black painted arm 
> nailed in the "yellow" position to a silver painted post.  An amber lamp is 
> placed where the arm meets the post.  Most other railroads (BN, NYC, etc) 
> forego a new construction and simply place retired semafores permanently set to
> the yellow position as inoperative approaches, and some use target signals set
> to yellow.  
>   Around 1986, a sign with the letter "D" began to appear on the inoperative 
> approaches signals of all the railroads I've seen.  It at least provides quick 
> identification of the signal's purpose, but may have another meaning.  Just 
> what the "D" stands for, I have no idea.

My NORAC rulebook I have(Conrail,Amtrak, and others) shows a signal which
is probably their version. It looks like this:
 ___          
/y  \   y|  | /\ 
| y |    |  |/ /
\  y/    A  y_/
 ---     |  |
  |      |  A
  y      |  |
  |      |  |

It's rule 293c and says Approach Restricting, and it's indication is
Proceed prepared to stop at hand-operated switches and at the next signal.
Trains exceeding Medium Speed must begin reduction to Medium speed as soon
as the engine passes the Approach Restricting signal. NOTE: Does not convey
block or track information.
There is also an Approach Clear, which is Rule 293b, which says Proced. NOTE:
Does not conver block or track information. It looks the same, except
the it doesn't show the Pennsy-style signal, and the yellow is replaced
with green(of course the blade is pointing up also)

I would assume this would be for the same situation, except maybe not
at a diamond, but maybe at an interchange with a branch line or something.

Fred Ochs
31ochs@gw.wmich.edu  (vax)
ochs@sol.cs.wmich.edu (unix)
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A DASH 8-40CW with a little imagination ;^)

Newsgroups: rec.railroad