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Trackside signal heads and what they mean..?

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Posted by cx500 on Tuesday, January 08, 2019 11:24 PM

Where speed signalling is the method of operation (probably the most common in North America), the signal at the entrance to the siding is used to convey two separate pieces of information.  The most immediate item is the position of the switch (normal, reversed, or out of register).  If the latter it had better be red!  Second is allowable speed through the turnout depending on its geometry.

The second is occupancy of the track on the selected route beyond, IF KNOWN.  While the main track will almost certainly have track circuits, as a cost saving measure the siding may be unbonded, hence dark territory.  As others have been insisting, it is the combination of the two (or three) heads that convey the full meaning.

For the simple situation of a passing siding on single track main line, the signal indications do superficially resemble how the OP has interpreted them, but the logic is a lot more complicated.

And in the category of exceptions, at one junction I am aware of, the clear signal was for the diverging side of a turnout since that was the the alignment of the subdivision.  Tracks 1 and 2 were 50 mph (no turnout) and Track 3 was 25mph because of that turnout.  Shown in the employees timetable, not by signal indication.  Straight through on the turnout had a more restrictive indication, probably mostly due to following parts of the route.  It snaked across two double track main lines before joining another subdivision on the diverging side of a turnout. 

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Posted by jeffhergert on Wednesday, January 09, 2019 6:26 PM

Where I work, there is one location (a junction point) where the best signal possible is a red over green no matter if you're going straight or on the diverging route.  The top light is a dummy, constantly lit red light.  The reason being that the straight route joins one of the mains coming into the junction, going through the diverging portion of that turnout.

A signal with a constant red light on top, making all signal indications being a "diverging" signal are not unusual.  The ones I'm familiar with are at locations where a main track ends or joins another main track and trains using that route are going through the diverging portion of the turnout.  

Jeff

 

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Posted by CGW121 on Friday, January 11, 2019 7:56 AM

Yellow over yellow: advanced divirging  rule 235 Wisc Central rr rule book 1998. I saw a friend last evening. He was a yardmaster with the UP for at least 10 years. He knew what it meant and what rule it is on the UP. Point is if you want to know ask the guy who works with it for a living. 

 

 

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Posted by jeffhergert on Friday, January 11, 2019 11:47 PM

CGW121

Yellow over yellow: advanced divirging  rule 235 Wisc Central rr rule book 1998. I saw a friend last evening. He was a yardmaster with the UP for at least 10 years. He knew what it meant and what rule it is on the UP. Point is if you want to know ask the guy who works with it for a living. 

 

 

 

On the Union Pacific it's called approach diverging.  May be called and mean something different on another railroad.  That's why when talking about specific signals one needs to specify railroad and even era (year).

Jeff

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Posted by CGW121 on Saturday, January 12, 2019 7:16 AM

jeffhergert

Also in the case of larger railroads that have aquired several other railroads, you can have different rules on different districts. Its not a quessing game thats part of being qualified on a route

 

 
CGW121

Yellow over yellow: advanced divirging  rule 235 Wisc Central rr rule book 1998. I saw a friend last evening. He was a yardmaster with the UP for at least 10 years. He knew what it meant and what rule it is on the UP. Point is if you want to know ask the guy who works with it for a living. 

 

 

 

 

 

On the Union Pacific it's called approach diverging.  May be called and mean something different on another railroad.  That's why when talking about specific signals one needs to specify railroad and even era (year).

Jeff

 

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Posted by dehusman on Saturday, January 12, 2019 9:20 AM

jeffhergert
That's why when talking about specific signals one needs to specify railroad and even era (year).

On the railroad I'm modeling, in 1900, signals would have been white for clear, green for caution and red for stop.  In 1903,  signals would have been green for clear, yellow for caution and red for stop. 

Dave H. Painted side goes up.

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Posted by mbinsewi on Saturday, January 12, 2019 9:39 AM

Dave, sounds like an interesting modeling adventure.

Would there have been some 5' or more, track gauges back then?

It looks like the OP has decided not to join in any of this.  As usual.

Mike.

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Posted by dehusman on Saturday, January 12, 2019 9:44 AM

mbinsewi
Would there have been some 5' or more, track gauges back then?

Most of the lines were "standard gauged" by the mid 1890's.  Most of the 5 ft gauge lines were in the south and west.

Dave H. Painted side goes up.

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Posted by zugmann on Saturday, January 12, 2019 10:03 PM

jeffhergert
On the Union Pacific it's called approach diverging. May be called and mean something different on another railroad.

We call it approach slow on Norac-type places.

 The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by ATLANTIC CENTRAL on Sunday, January 13, 2019 9:28 AM

zugmann

 

 
jeffhergert
On the Union Pacific it's called approach diverging. May be called and mean something different on another railroad.

 

We call it approach slow on Norac-type places.

 

And here in lies the problem with discussing prototype railroad signaling practice on a model railroading forum.

Many of us who are interested in model trains have no interest or indepth knowledge of current prototype practice. Because many of us do not buy/build models of current trains.

On my little railroad, it is always September 1954, long before the creation of NORAC in 1985.

And I even control my little signals with relay circuits almost identical to those used on the big railroads in 1954.

What is going on with that rusty, graffitti covered mess that passes for railroading today is of little interest to me.

And I may not have any real world experiance working on the prototype, but my son does, and so do a number of my friends........

So please excuse my lack of interest in your current railroading knowledge, I want to know more about signals from 70 years ago.

Sheldon

    

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Posted by mbinsewi on Sunday, January 13, 2019 10:07 AM

ATLANTIC CENTRAL
And here in lies the problem with discussing prototype railroad signaling practice on a model railroading forum.

As I've learned, from this thread and others.  Just too much information, some of it conflicting.

I have NO club experience.  How does a club handle signaling?  I'm guessing they come up with some kind of an SOP, so everyone who operates on it is on the same page.

But I don't know.

Mike.

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Posted by ROBERT PETRICK on Sunday, January 13, 2019 10:33 AM

mbinsewi
ATLANTIC CENTRAL
And here in lies the problem with discussing prototype railroad signaling practice on a model railroading forum.

As I've learned, from this thread and others.  Just too much information, some of it conflicting.

I have NO club experience.  How does a club handle signaling?  I'm guessing they come up with some kind of an SOP, so everyone who operates on it is on the same page.

But I don't know.

Mike.

I can tell you how my previous club handled signaling . . . they talked about it. That was fifteen years ago. I bet they're still talking about it.

Robert 

LINK to SNSR Blog


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Posted by zugmann on Sunday, January 13, 2019 12:18 PM

ATLANTIC CENTRAL
So please excuse my lack of interest in your current railroading knowledge, I want to know more about signals from 70 years ago.

 I apologize for making a comment on here.   How silly of me.

 

 The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by dehusman on Sunday, January 13, 2019 12:47 PM

ATLANTIC CENTRAL
Many of us who are interested in model trains have no interest or indepth knowledge of current prototype practice. Because many of us do not buy/build models of current trains.

ATLANTIC CENTRAL
So please excuse my lack of interest in your current railroading knowledge, I want to know more about signals from 70 years ago.

That's too bad.  The underlying concepts are pretty much the same as they were 100 years ago.  

I would give you some examples, but I don't want to distract you with "modern stuff."

Dave H. Painted side goes up.

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Posted by ATLANTIC CENTRAL on Sunday, January 13, 2019 4:22 PM

dehusman

 

 
ATLANTIC CENTRAL
Many of us who are interested in model trains have no interest or indepth knowledge of current prototype practice. Because many of us do not buy/build models of current trains.

 

 
ATLANTIC CENTRAL
So please excuse my lack of interest in your current railroading knowledge, I want to know more about signals from 70 years ago.

That's too bad.  The underlying concepts are pretty much the same as they were 100 years ago.  

I would give you some examples, but I don't want to distract you with "modern stuff."

 

Dave, you are the only person on "your side" of this discussion who does not seem to have an attitude towards us "lowly modelers" who are not real world railroaders.

Have you read the unicorns profile page?

I understand everything you have explained, and most I already understood. 

My point remains, a point you have made repeatedly as well from your prespective, signaling cannot be boiled down to a few simple "rules". 

It is complex, its history in North America is long and complex, its applications today and in the past are complex.

I just got a little tired of "NORAC says.....", as if to imply that is the beginning and end of railroad signals. NORAC does not exist in my model world......

I have been considering a reply to the earlier part of thread in which you tried to explain to Ed about the application of signal indications and rules.

You are right, very few rule books make any reference to turnouts or diverging routes regarding particular signal aspects.

BUT, from the other side, from the seat of the guy who designs the system, the guy who figures out the relay logic to control those lights, a truth table of questions must be written for each signal head individually.

And if a turnout, or multiple turnouts are involved, those are the first pieces of information in the chain for the top head on the mast, for any given track.

If a trailing point turnout is set against that track, that top head will be red, unless there is a facing point turnout before that set to put the train on a different route. And if not, they all better be red......

From the system designers standpoint, the typical control point or interlocking, particularly with CTC, does often relate the top head to the main route, the second head to the next route, and the third head to the route beyond that, etc.

Yes, they may be cross interlocked to provide special indications, but the design process starts there.

I have studied prototype wiring diagrams, I have studied and designed relay based model systems.

That might not be how we want train crews to read them, but it is largely how the aspects are created on an equipment level as it relates to junctions, crossovers, diverging routes that are signal controlled.

The final two links in the chain are "is there a train in front of me on the route I have been given?", and if it is CTC, "did the dispatcher say I could have the route?".

After all that the relays and track circuits will give me that magic selection of colored lights that fit the situation, and it is my job to control my train accordingly.

But as a modeler, not all of us want to just wire inputs and outputs to a logic device (computer, PLC, etc) and rely on software someone else created to get aspects someone else told us were correct.

Some of us want to understand why that track/route/occupancy/authority chain created that set of aspects.

For which I would refer anyone to Bruce Cubb's first signal system published in MR, or Ed Ravenscoft's MZL control.

Sheldon

 

 

    

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Posted by zugmann on Sunday, January 13, 2019 11:06 PM

ATLANTIC CENTRAL
Dave, you are the only person on "your side" of this discussion who does not seem to have an attitude towards us "lowly modelers" who are not real world railroaders. Have you read the unicorns profile page?

I don't think I ever gave an attitude towards any "lowly modelers".  If I have, please show me where?  I even dabbled in model trains (2 different gauges) a few times in my life (although not currently).

Second, it's actually an alicorn, not a unicorn.  Not that it matters, but my profile page?  In case we haven't formally met, I am zug, and I'm pretty much known for my warped humor.

 

I just replied with my approach slow since Jeff named what the signal is under his rulebook.  Nothing nefarious in it, no attempts to insult anyone, and I don't think I'm a higher being becuase I carry around a copy of NORAC.   Be a weird litmus test... would a demon carry GCOR? 

You do you... you can model whatever you want.  That's cool.

I look at this page from time to time since it is about protoype information for the modeler, and since I qualify for the first part, I share information.  Nobody has to read it or take it seriously if they don't want to. 

 

I'm sorry if that offended you.  My apologies, again.  

 The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by ATLANTIC CENTRAL on Monday, January 14, 2019 4:38 AM

zugmann

 

 
ATLANTIC CENTRAL
Dave, you are the only person on "your side" of this discussion who does not seem to have an attitude towards us "lowly modelers" who are not real world railroaders. Have you read the unicorns profile page?

 

I don't think I ever gave an attitude towards any "lowly modelers".  If I have, please show me where?  I even dabbled in model trains (2 different gauges) a few times in my life (although not currently).

Second, it's actually an alicorn, not a unicorn.  Not that it matters, but my profile page?  In case we haven't formally met, I am zug, and I'm pretty much known for my warped humor.

 

I just replied with my approach slow since Jeff named what the signal is under his rulebook.  Nothing nefarious in it, no attempts to insult anyone, and I don't think I'm a higher being becuase I carry around a copy of NORAC.   Be a weird litmus test... would a demon carry GCOR? 

You do you... you can model whatever you want.  That's cool.

I look at this page from time to time since it is about protoype information for the modeler, and since I qualify for the first part, I share information.  Nobody has to read it or take it seriously if they don't want to. 

 

I'm sorry if that offended you.  My apologies, again.  

 

This thread has had a lot of missunderstood back and forth, and I am sorry if I included you with some others who seem to set themselves up as "experts" without understanding the context of this being the model railroad forum.

Again, my appolgies as well.

Sheldon

    

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Posted by dehusman on Monday, January 14, 2019 7:01 AM

ATLANTIC CENTRAL
I just got a little tired of "NORAC says.....", as if to imply that is the beginning and end of railroad signals. NORAC does not exist in my model world......

NORAC is derived in large part from the Penn Central rules which was derived in large part from the PRR rules.  The major difference in signal rules between a 1951 PRR rule book and a 2000 era NORAC rule book is they didn't have flashing aspects in 1951 (and there are a couple signals related to manual block in 1951 that didn't exist in 2000).

If you are reading NORAC you are more or less reading a PRR rule book.  That is a problem because the PRR, while it may have been called the "standard railroad of the world", was anything but standard with respect to the rest of the industry.

Even the PRR yard limit rule is different from virtually every other rule book.

You will also find that the Consolidated Code of Operating Rules (CCOR) is oft quoted in model railroad circles.  I can only think it was popular because many of the roads went through Milwaukee and that was Model Railroader's headquarters so that's what the MR guys had.

Dave H. Painted side goes up.

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Posted by cv_acr on Monday, January 14, 2019 8:54 AM

Modern rulebooks (NORAC, GCOR, CROR, etc.) didn't just come out of nowhere and change the meaning of all the signals and make the railroads change them all. It's just an evolution and update of existing rulebooks and the signal information will simply carry forward from what was already in use. Most of the signal rules will be the same as decades-older rulebooks, and there are locations out there with 50+ year old original signals still in place still working as they did when first installed...

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