What is a Home Signal?
A Home Signal is another name for an Absolute Signal, i.e. one directly controlled by the Dispatcher. It will not have a number plate. Other signals are called Intermediate Signals, They are controlled by track circuits only. The Intermediate Signal just before a Home Signal is called a Distant Signal. Intermediate Signals normally only have one signal head, and only one light will be lit.
“Home signal” is an old and now obsolete name for an absolute signal at the entrance to an interlocking or controlled siding. The home signal may be controlled or uncontrolled; at an automatic interlocking, for example, the home signals are absolute but uncontrolled.
In a simple interlocking plant, for example a crossing at grade of two railroads in otherwise unsignaled territory, there would be four home signals, one protecting each entrance, and four distant signals. The distant signals would only provide advance notice of the indication of the home signal, and unlike an intermediate signal would not provide any information about track conditions between the distant signal and the home signal. Many distant signals in fact were (and are) fixed aspect, displaying only yellow.
A more complicated interlocking plant, for example with a siding with power-operated or operator-controlled turnouts, would require leaving signals to protect the turnouts.
Many railroads now use multiple heads on intermediate signals to give speed-signal aspects.
Technically on a GCOR-governed railroad a distant signal refers only to the special case above, and the signal is marked with a “D” plate to differentiate it from an intermediate signal.
There were some cheap ABS installations before WWII that consisted of home signals at siding ends and distant signals protecting them; the only signals that provided information about track conditions were the home signals and the leaving signals.
S. Hadid
So, if we don’t call them home signals any more, what do we call them?
They still call them home signals around here…
If the home signal is red, is it an absolute red (i.e., come to a halt)?
Yes. Absolutely.
From my current Operating Rules book:
Home Signal: A fixed signal, capable of displaying a STOP indication, governing the entrance to an interlocking or controlled point.
Controlled Signal: A fixed signal capable of displaying a STOP indication, that is controlled by a dispatcher or operator.
Distant Signal: A fixed signal used to govern the approach of a train to a home signal.
Automatic Signal: A block signal that is activated either by track circuit or in conjunction with interlocking or controlled point circuits. This signlal automatically indicates track condition and block occupancy.
Nick
I never cease to be amazed how eastern roads and western roads use different operating nomenclature and different operating rules but the outcome is exactly the same. I can read a NORAC rule book and understand it but it’s almost like it’s written in a foreign language.
Thanks for the excerpts.
S. Hadid
I know. Everytime you or Ed quotes a GCOR rule…I have to scratch my head for a minute, and remember the appropriate NORAC rule.
Maybe we need a GCOR to NORAC dictionary. [:P]
Nick
Another wrinkle to concider. Home signals can be distant signals for other home signals. Here an exercise I used when I did rules instruction. Although I used flash cards to show how the signals interacted.
<—W E—>
A B C D E
===|=========|===========/=========/======|====
C & D are Home Signals for interlockings - they are Absolute.
A & B & E are Automatic Block Signals - they are Permissive.
There are no signals between C & D.
Traveling East:
B is the Distant Signal for C.
C is the Distant Signal for D.
Traveling West:
E is the Distant Signal for D.
D is the Distant Signal for C.
Signal A in both directions and Signals B & E, when traveling away from the interlockings, will usually only have one head, and display Clear, Approach or Restricted Proceed.
Signals B & E - approaching the interlockings, may have two heads to display speed information for approaching C & D. They can display Clear, Approach Limited, Approach Medium, Approach Slow, Approach or Restricted Proceed. This is based on the signal and the route lined at C or D.
Because no signal intervene between C & D:
Traveling East C will tell you how to approach D.
Traveling West D will tell you how to approach C.
Nick
Yes, Nick, a home signal can be a distant signal for another home signal, but it’s still going to be “stop and stay” if it’s all red.
Hey, you know what, if you have two control points that close, and the first one has a medium-speed diverging route and the second one [on said route] has a slow-speed diverging route, how would you know you were going to take that route? Medium Approach Slow, of course!
Carl,
I didn’t mean to imply that when Home Signals are Distant Signals, they weren’t Absolute. Of course, they are. Any Absolute signal, is always Absolute.
NORAC doesn’t have a Medium Approach Slow. So you’d probably get an Approach Slow, or possibly a straight Approach.
Nick
I thought you asked about that aspect on the “shootout” thread a while back. Just making a feeble attempt to look intelligent.
By the way, I guess we GCOR folks are supposed to call home signals “Interlocking signals” now.
We don’t used “mediums” or “slows” in GCOR country, either–we just diverge at the prescribed speed.
Carl,
You’re right…I did make a comment about the M-A-S signal. Being a NORAC man…I couldn’t see the need for it in the Seaboard rules.
We still use Medium and Slow signals, but the actual speeds through the diverging route, are governed by the speed listed in the Timetable.
Nick
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Do you think NORAC and GCOR will ever get together on a common rule book?
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What do Canadian Railroads use? Is it different from what they use while operating in the USA? - a.s.
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I have no idea.
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Canadian railways use Canadian Rail Operating Rules, CROR http://www.tc.gc.ca/railway/cror.htm
CROR is as “different” from GCOR or NORAC as GCOR and NORAC from each other. But the logic is identical and the outcome the same – just different ways of organizing things. The point is that there is no significant disagreement worldwide on the basic principles of railway operation and safety. You can go to India or Russia or Germany, read the rule book, and you’ll find the same concepts and principles.
S. Hadid
So, when I listen in on the NS and the CSX I hear different types of signals called:
NS - Approach diverging, Diverging approach, Diverging clear, etc
CSX - Approach medium, Medium clear,etc.
It appears to me that the NS is a routing aspect while the CSX’s are speed aspects. Which rulebooks cover each situation?
ed
It’s not so much the rulebook as the timetable that determines that. The rulebook covers overall operation, the timetable addresses the railroad specifically.
In terms of operations and safety that may be true but in terms of signaling that statement is very untrue. Canada and the USA have implemented a system of aspects that are very different than what most if not all of the rest of the world have implemented. For example the use of red does not mean in any way shape or form “stop”. As a CROR example green over two reds means full authorized track speed. The color in no way shape or form means a given ‘class or range’ of speed. For example CROR red over two flashing yellows means “slow to slow”. USA and Canadian signaling systems are essentially the only systems that (a) the combinations of colors means a certain aspect, and (b) where each of three possible lamps very loosely correspond with a high-speed, medium-speed, and low-speed routes. However there are examples that contradict that logic. For example CROR red over flashing yellow over green means “slow to medium”. Since the third lamp is supposed to be the slow speed route wouldn’t its being green (thinking logically here) mean slow? Canadian and USA signals convey speed information but with route information implied. Red is often written as a 'ignore’or ‘placeholder’ indication, but even that holds little water. From what I can gather it seems over time, there was the requirement to get more aspects, mergers, and the persistant mentality to ‘make do with what we got’ that result in a system of aspects that can only be memorized, not logically understood.
Contrast that with most other countries around the world where they convery either route information specifcally, or speed/condition information, but not both 'mixed