i'm looking for a complete, correct and unambiguious description
greg - Philadelphia & Reading / Reading
Since its used by many different railroads you may be out of luck for one single definition.
NORAC 2003 : A station designated in the Timetable where signals are remotely controlled from the control station.
GCOR 2010 : A location of absolute signals controlled by a control operator.
The term doesn't appear in the half dozen or so rule books I looked at that dated 1980 or earlier.
Basically its a place where the signals are manually controlled.
Dave H. Painted side goes up. My website : wnbranch.com
PC used to also use them as a location to tell someone about an issue in that vicinity.
Joe
Hello All,
gregci'm looking for a complete, correct and unambiguious description
HERE!?!
I know this won't help!
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
Greg;
I believe the term "control point" is used to designate a location where a dispatcher can exercise route options, using manually controlled signals. This may be a passing siding, a junction or simply crossovers between two or more main tracks. The General Code of Operating Rules, effective on UP and SSW on, April 28, 1985, effective on the SP and ATSF on October 28, 1985, as well as the BN, CNW, DRI&NW, LS&I, SOO/MILW, and Minn. Trfr on April 27, 1986 makes no mention of a "control point". It does explain the definition of, controlled sidings and, controlled signal, as used on a CTC piece of railroad. I don't ever recall hearing the term control point used on any place but along the east coast. It must be regional usage just like a can of Coke is a "soda" in one state, a "pop" in another, and a "tonic" in another very small region of the country-yes New England, I mean you.
gregc i'm looking for a complete, correct and unambiguious description
Good luck with that.....
All the answers so far are correct.
Generally a series of absolute signals, generally on either side of an interlocking, controlled by a tower operator, dispatcher, or CTC operator.
It is the point of absolute control - do not cross on RED/RED/RED indications.
And yes the term seems to be, or have been, more common on east coast roads.
As an example, my simplified CTC for modeling only uses control point or "absolute" signals and their advance signals. Intermediate permissive automatic block signals are not modeled.
Sheldon
The overall problem with any discussion of signaling and/or CTC is that railroad, region and era effect everything in the discussion.
Not having a government controlled rail system, the US has had hundreds of similar but different signal systems on the hundreds of different railroads.
Applying the same terms to all of them, in every era, simply will not work.
The principles are all the same, the details are almost always different.
And then scaling them down to our models is another problem........
So Greg, once again I would suggest to you that you might get better answers if we knew the reason for your question? You always want to know why? Well I want to to know why you want to know.
Personally, I hate when people ask a leading question that is not the real question or does not contain all the info.
I thought it was a reasonable question.
From this list of railroad definitions, http://jcbd.com/rrterms.html, a controlled point is "A location where signals and/or switches of a traffic control system are operated and/or controlled from a distant location by a train dispatcher.".
maxman I thought it was a reasonable question. From this list of railroad definitions, http://jcbd.com/rrterms.html, a controlled point is "A location where signals and/or switches of a traffic control system are operated and/or controlled from a distant location by a train dispatcher.".
It's a reasonable question, but all the "qualifiers" make you wonder what the agenda is?
And your link does not seem to work?
Doesn't work?
Hmmmmm. Looks the same, but try this one:
http://jcbd.com/rrterms.html
If this doesn't work, let me know.
maxman Doesn't work? Hmmmmm. Looks the same, but try this one: http://jcbd.com/rrterms.html If this doesn't work, let me know.
Well, that's fine, that is pretty much the same as what myself and others said.
But who generated that list? Who are they? Who put them in charge of railroad terms? There is no ownership info on the page?
Oh for goodness sake. Sometimes I think folks are being argumentative just for the sake of being so. It's a list, it gave a simple definition, and it was concise.
Go bother someone else.
What is a "rivet counter"?
I'm looking for a complete, correct and unambiguious description.
And, don't refer me to that link. It's not on it.
Alton Junction
Maxman, I think the original link had a comma included in the link after the .html
York1 John
I asked my doctor if I gave up delicious food and all alcohol, would I live longer? He said, "No, but it will seem longer."
What is a rivet counter? Clearly it is the area in a hardware store where the selection of rivets is displayed.
coming to the conclusion that it's nothing more than a remotely or manually operated device such as a signal or switch.
i've been given the impression that it was much more than a signal, a route between signals in a interlocking/signaling system
gregccoming to the conclusion that it's nothing more than a remotely or manually operated device such as a signal or switch.
Primarily in the late 1950s and into the '60s there was a big economic push to eliminate signal towers or interlocking towers and reduce the manhours needed to move trains across the railroad.
Hundreds of manned towers were eliminated, replaced by relay cabinets and remote operated switches. Often they retained the name of the tower i.e. "Conpit" became C.P. Conpit.
Al Perlman on the New York Central was a "progressive" manager and he instituted a massive campaign to install CTC on the NYC and eliminate a gtrat deal of trackage and the associated sitnal towers.
Many of the Control Points are named for the milepost. Near me is C.P. 171 which is 171 miles west of Buffalo.
"Generally" where you find a control point there was once a signal tower there.
History:
https://ekeving.se/ctc/us/NYC_RS_1927.pdf
Throughout this 1927 article you will see the mention of remote control, as in controlled territory, controlled sidings and controlled signals. Thus you can see the extension of calling these specific locations — Control Points.
Regards, Ed
gregc coming to the conclusion that it's nothing more than a remotely or manually operated device such as a signal or switch. i've been given the impression that it was much more than a signal, a route between signals in a interlocking/signaling system
That's the point Greg, on some railroads, in some eras, it would be each end of a large complex interlocking.
And in other situations it may just be each end of a dispatcher controlled siding on a single track line in the middle of no where.
Signaling is not an absolute science, and again, back in the day each railroad designed and built what worked for them.
I studied signaling for years before deciding how to model it. I studied the prototype, and I studied what others had done over many decades in the model world to simulate it.
My suggestion to anyone in this hobby interested in signaling a layout is to simplify whatever prototype they want to follow because our model situations simply do not lend themselves to the complexities of the prototype - even on the largest club layouts.
Our distances are too short, and most of our operators are not really interested in learning a complex system.
And not that many viewers will ever know the difference.
So why not make it practical in guiding operators, and interesting to viewers, and leave it at that?
On my layout, there are never more than two signal blocks between interlockings, and in many cases only one. All interlockings are "control points", although I don't really bother with that term. I simply use the terms "interlocking" and "signal block". All CTC trackage is one or the other.
The CTC dispatcher sets routes (turnout positions thru interlockings) and then gives authority (clear signal) - I use pushbuttons, not levers, and one or at most two buttons typically align all turnouts for a route. One additional button then assigns the next block to the train which gives it a clear signal. Once in a specific block, detection turns signals at both ends of the block to absolute stop.
Without a dispatcher on duty, walk around control allows engineers or tower operators to make these assignments at each local tower.
And if you run a RED/RED/RED signal, you will find your train has no power before it makes it all the way thru the interlocking.
And it does not even take a micro processor to do this...... but you could use one if you wanted to.......
A "controlled point" is generally an interlocking that is operated from somewhere else.
It might even be nothing more than a signal controlled remotely by the dispatcher (even though there are no switches associated with it).
A CP generally isn't going to have "manually operated" switches -- how would the dispatcher or operator throw them from a remote location?
Now and then, you WILL find a manual switch within the limits of an interlocking, but it will be thrown by the members of a train crew, after receiving permission (or "the unlock") from the dispatcher or operator.
Examples of controlled points might be CP 72 and CP 75 on the Metro-North Hudson line, south and north of Poughkeepsie.
An example of a controlled signal would be found north of Hudson station on the Hudson line, governing southward movements. I can't remember if they actually made this "CP 115" or not, it's been too long since I was there.
I recall a manually-operated switch in the middle of CP 89 (just north of Rhinecliff) on the Hudson line, that once connected to the old CNE. Again, it's been a long time, 30 years since I worked up that way.
NHTX I don't ever recall hearing the term control point used on any place but along the east coast.
Nope, they are used all over the country. The UP and BNSF have hundreds, if not thousands of them. And the majority weren't interlocking towers previously either, some were but there are way more that were created when the lines were CTC'd. The term CP really took off when the NORAC and CGOR rule books were written.
gregccoming to the conclusion that it's nothing more than a remotely or manually operated device such as a signal or switch. i've been given the impression that it was much more than a signal, a route between signals in a interlocking/signaling system
As has been said several times, a control point is a controled signal (per GCOR and Norac definitions).
The reason you have controled signals is you want to control trains operating over switches or on different routes. So yes there will commonly be switches associated with a CP and where there are switches there will be multiple routes.
CP's come in all sorts of shapes and sizes and histories of how they got there. There is no one simple description that covers every option in detail. In the modern era the line between CTC-CP-Interlocking gets blurred somewhat. Prior to the 1980's the term CP wasn't used, CTC and interlockings had different rules (very similar but with some differences).
Don't make this more complicated than it is.
gmpullmanhttps://ekeving.se/ctc/us/NYC_RS_1927.pdf
thanks again Ed
dehusmanNORAC 2003 : A station designated in the Timetable where signals are remotely controlled from the control station. GCOR 2010 : A location of absolute signals controlled by a control operator. The term doesn't appear in the half dozen or so rule books I looked at that dated 1980 or earlier.
The CTC system would allow the flow of traffic to be set over many sections of track by a single person at a single location as well as control of switches and signals at interlockings, which also came to be referred to as control points.
The majority of control points are equipped with remote control, power-operated switches.
if you were adding CTC/signals to your layout, how would you identify the CPs? or is it more about defining the interlocking logic that the CTC system uses to determine the signal indication based on actual switch position, CTC signal lever setting and block occupancy of associated trackage?
the following from Orville Interlocking Tower might be a good example to consider
gregc if you were adding CTC/signals to your layout, how would you identify the CPs? or is it more about defining the interlocking logic that the CTC system uses to determine the signal indication based on actual switch position, CTC signal lever setting and block occupancy of associated trackage?
Exactly - define what the interlocking needs to do, and that will establish the control points, not the other way around.
Can I toss some gas on the fire?
Reading archived accident reports from the NTSB, there's always a mention of the last control point. They are always listed as manned, or open. Most read like " train xxxx past so and so interlocking tower which is the last manned control point." Or " train xxx passed through signal xxx which is the last open control point."
While these examples come from steam era reports, one has to assume that control points were manned stations, towers, or platforms where train orders, and signals were given to direct train movements over a section of the railroad. Either a block, branch, yard, or station. I could not find the glossary of terms or definitions on the NTSB's website.
Pete.
wrench567They are always listed as manned, or open. Most read like " train xxxx past so and so interlocking tower which is the last manned control point." Or " train xxx passed through signal xxx which is the last open control point." While these examples come from steam era reports,
Be careful with eras here. In the steam era, CTC (rule 261) was not as common as it is today, and "control points" were not defined in railroad rule books.
One also needs to remember that there won't be any "steam era" NTSB reports since it wasn't created until 1967, well after the steam era. Any truly steam era reports on accidents would probably be ICC reports.
One also has to remember that the signal and control systems, the actual design, operation and, maybe most importantly, communication systems were vastly different in the steam era than in a more modern era, so the concept, definition and function of a control point might be different.
gregcif you were adding CTC/signals to your layout, how would you identify the CPs?
You are kinda going backwards. A control POINT is a location. Its the signal equivalent of a STATION.
Orville could be just one CP.
Once again, don't read more into a CP than is there. There are all the rules and operational considerations for interlockings and for CTC. There are NO "CP rules". Don't attribute stuff that is a CTC, interlocking or general signal design thing to a "CP". A CP is designated to identify a group of locgically and operationally connected switches and signals.
dehusman wrench567 They are always listed as manned, or open. Most read like " train xxxx past so and so interlocking tower which is the last manned control point." Or " train xxx passed through signal xxx which is the last open control point." While these examples come from steam era reports, Be careful with eras here. In the steam era, CTC (rule 261) was not as common as it is today, and "control points" were not defined in railroad rule books. One also needs to remember that there won't be any "steam era" NTSB reports since it wasn't created until 1967, well after the steam era. Any truly steam era reports on accidents would probably be ICC reports. One also has to remember that the signal and control systems, the actual design, operation and, maybe most importantly, communication systems were vastly different in the steam era than in a more modern era, so the concept, definition and function of a control point might be different.
wrench567 They are always listed as manned, or open. Most read like " train xxxx past so and so interlocking tower which is the last manned control point." Or " train xxx passed through signal xxx which is the last open control point." While these examples come from steam era reports,
Thank you Dave, I tried to make that point early on.....
dehusmanOnce again, don't read more into a CP than is there.
unfortunately, there's not much to read
so a CP is not simply a signal, but a group of signals, switches and tracks under the control of a single tower, for example.
In my defense. I know the ICC investigations is no more. I found the archives from the NTSB web site. From 1911 through 1965. There is some good reading in the reports and one can spend an entire night just skipping through. I don't know if it's the NTSB or the National archives that maintains the list. I believe it is the National archives. It could be the DOT even. Whoever maintains the list I found it through the NTSB's website.
gregcso a CP is not simply a signal, but a group of signals, switches and tracks under the control of a single tower, for example.
No. A CP is "the location of absolute signals controlled by a control operator." (GCOR 2010).
There is no requirement for switches, there is no requirement for a "tower". There could be, but there doesn't have to be. Probably 90-95% of all the CP's are just one end of a siding. No towers, just one switch.
The KEY is that there is a location with a manually controlled signal or signals (see GCOR). There can be lots of other stuff, but what defines it is there is the manually controlled signal.
An interlocking may be a CP or it may not.
A CP can be in CTC or it may not.
That's why I keep saying don't read more into a CP than is there.