is it "on sheet" or "on switch"?
i've read that a station manager (?) will note the arrival/passing/departure of a train at a particular station on a record sheet.
from a signaling/interlocking perspective, it seems to refer to a relatively short block with one or more switches used to recognize that a train is on the switch to prevent the switch from being thrown while occupied.
greg - Philadelphia & Reading / Reading
I've heard "O.S." as meaning "On Sheet", meaning that a train has passed a particular station or tower and has been recorded 'on the sheet' as having passed at such-and-such a time. I've not heard "O.S. Section" before, so not sure what that would mean?
Two different things in your question.
With TT/TO an "OS" is a report from the operator to the dispatcher that a particular train has passed. The operator would ring up the dispatcher and announce himself with the hail "OS <station name>" and then they would report the train information. The rule book identifies that "OS" is a proscribed abbreviation* to use when reporting, but not a history for why those letters. "On sheet" has long been touted as a possible original meaning (as the dispatcher will use the reported sighting to update the train's progress by writing in the time on his train sheet). "Operator sighting" might also be logical. Or maybe "operator station", as the operator calls in with "OS <station>" to identify himself...
(* Literally the only reference in my rulebook is under "approved abbreviations" [to be used in orders and/or other communications]: OS = Train Report)
"OS Section".... I have heard people use that term to refer to the short block in an interlocked CTC control point. (i.e. usually just the length of the controlled siding switch) Not sure how that gets its name exactly, other than perhaps from the train crossing through this point is what the dispatcher would be able to use to actually mark a train's position/progress - i.e. since the track block is so short it's essentially a point reference, and the CTC machine/computer will show the train occupying and clearing the point, essentially providing the dispatcher his "OS". (Trackside operators don't exist anymore...)
Chris van der Heide
My Algoma Central Railway Modeling Blog
In signaling, usually refers to CTC or intelockings, it is typically a section of track that includes a switch that indicates occupancy of the switch.
If the switch is occupined then the train has left the station, OS'd. Which translation you want to apply is immaterial, they all have the same effective meaning, the train has "left" the station.
Dave H. Painted side goes up. My website : wnbranch.com
wjstixI've heard "O.S." as meaning "On Sheet"
There are about a half dozen different translations of what "OS" means. Really doesn't matter which translation you use, the effective meaning is the same, the train has departed the station.
i thought it does matter from an interlocking point of view.
if there's a junction with a single CTC controlled switch, wouldn't control of the switch be inhibited if there was a block just covering the switch that was occupied?
signals would depend on the occupancies of blocks on either sides of the switch
such a situation would have nothing related to being "on sheet"
gregc i thought it does matter from an interlocking point of view. if there's a junction with a single CTC controlled switch, wouldn't control of the switch be inhibited if there was a block just covering the switch that was occupied? signals would depend on the occupancies of blocks on either sides of the switch such a situation would have nothing rela ted to being "on sheet"
such a situation would have nothing rela ted to being "on sheet"
He's saying whatever the original words that leant themselves to the "O.S." shorthand for "train report" doesn't make any difference.
That has nothing to do with how the interlocking locks things out.
cv_acrHe's saying whatever the original words that leant themselves to the "O.S." shorthand for "train report" doesn't make any difference. That has nothing to do with how the interlocking locks things out.
Dave said it boils down to "the train has departed the station".
but the situation i described at a junction isn't at a station, or is it?
A few years ago, the UP site had something, I don't remember what the actual discussion was about, where they said OS meant "over switch" This probably came from a person who only knew OS from the OS sections of control points. Someone who never knew about open depots/towers and telegraph calls, etc.
There were enough comments from those who DID remember and the majority consensus was that OS derived from "on sheet." The time(s) entered on a station/tower's record of train movement. I fall into that category.
Does it really matter now what the telegraph call derived from?
When a train arrives at it's terminating station. One from which it won't depart, how would the operator call the dispatcher to report it in? "O S, (station)."
Jeff
gregcif there's a junction with a single CTC controlled switch, wouldn't control of the switch be inhibited if there was a block just covering the switch that was occupied?
Yes.
signals would depend on the occupancies of blocks on either sides of the switch such a situation would have nothing related to being "on sheet"
If the train moves over the switch then its has departed the station. If there is a train movement its written on the "sheet" (train sheet or record of train movements) either manually or virtually.
gregcDave said it boils down to "the train has departed the station". but the situation i described at a junction isn't at a station, or is it?
If it is a junction it will be named, if its named it's a station.
dehusmanIn signaling, usually refers to CTC or intelockings, it is typically a section of track that includes a switch that indicates occupancy of the switch.
the diagram illustrates a siding, blocks (e.g. B20), switches (e.g. T23b) and three OS sections (e.g. OS2) are identified and used as separate inputs into interlocking logic
Dave's description suggests that the OS section may encompass the entire siding, not have 3 separate OS sections defined in the case below. is this correct?
gregcDave's description suggests that the OS section may encompass the entire siding, not have 3 separate OS sections defined in the case below. is this correct?
How would you get that I said it encompasses the whole siding when I said it was the part with the switch?
T23a, T23b and T17 are the "OS sections".
cv_acr"OS Section".... I have heard people use that term to refer to the short block in an interlocked CTC control point. (i.e. usually just the length of the controlled siding switch) Not sure how that gets its name exactly, other than perhaps from the train crossing through this point is what the dispatcher would be able to use to actually mark a train's position/progress - i.e. since the track block is so short it's essentially a point reference, and the CTC machine/computer will show the train occupying and clearing the point, essentially providing the dispatcher his "OS".
Exactly. Occupying the OS section provides a timestamp for train movements. It reports an arrival, departure or passing time at that location.
It would not be surprising if "OS" originally wasn't an abbreviation for "On Sheet" or anything else. It may have just been a code chosen to indicate a train had passed because it was easy to send and remember. Kinda like how SOS doesn't mean "Save Our Ship", it's just a real easy Morse code message to use - three dots, three dashes, three dots etc. etc.
gregc but the situation i described at a junction isn't at a station, or is it?
"Station" is defined in the rulebook as ANY named point (with a station name sign). There doesn't even need to be ANYTHING else in terms of buildings, sidings or other switches there.
wjstix It may have just been a code chosen to indicate a train had passed because it was easy to send and remember. Kinda like how SOS doesn't mean "Save Our Ship", it's just a real easy Morse code message to use - three dots, three dashes, three dots etc. etc.
It may have just been a code chosen to indicate a train had passed because it was easy to send and remember. Kinda like how SOS doesn't mean "Save Our Ship", it's just a real easy Morse code message to use - three dots, three dashes, three dots etc. etc.
When you consider that the earliest operators all communicated via telegraph not telephone, this actually makes a lot of potential sense to me. The "_ _ _ ..." tones being a recognizable call.
Each operator station also had their own two-letter call symbols listed in the timetable.
Whatever the original meaning of "OS" (if it ever had one), it was over 100 years ago and it lost to time.
I rather doubt the original meaning was "over switch" or "on switch" or "on signal" since a train can be OS'd by an operator where there are no signals or switches.
As other's have said, it really doesn't matter what the origin wasn, regardless of the translation is, an OS is a report of train movement, arrival, departure or passing.
dehusman gregc Dave's description suggests that the OS section may encompass the entire siding, not have 3 separate OS sections defined in the case below. is this correct? T23a, T23b and T17 are the "OS sections".
gregc Dave's description suggests that the OS section may encompass the entire siding, not have 3 separate OS sections defined in the case below. is this correct?
dehusmanReally doesn't matter which translation you use, the effective meaning is the same, the train has departed the station.
dehusmanan OS is a report of train movement, arrival, departure or passing.
ok
but now i'm curious, is each switch technically a station?
gregcbut now i'm curious, is each switch technically a station?
No.
I return to what I posted above:
"Station" is defined in the rulebook as any named point (with a station name sign).
Generally the entire siding and any other associated switches are associated with that station.
cv_acr"Station" is defined in the rulebook as any named point (with a station name sign).
Technically, any point named IN THE TIME TABLE.
If its not named in the time table, then its not a station.
If each switch is named separately in the time table, then yes. If not, then no.
If the siding at Anna has East Anna and West Anna in the timetable (increasingly common in this GPS, measurement down to the nearest yard world we live in) then yes. If the time table just lists Anna as the siding then no.
However as OS's go, the railroad will measure the departure of a westward train at Anna when it passes the west switch and the departure of an eastward train when it passes the East switch, regardless of whether or not the switches are "stations".
The original OS was for On Sheet. It was when the train arrived at or passed a manned location.
Now with the the use of DTMF controlled turnouts there is an OS section that if anything is in that section the turnout will not operated until what ever is in the circuit is moved out.
SOS for ships has no words that it is short for. It picked because it was easy to key and wouldn't be confused with any other messages or words.
Richard
fire5506 The original OS was for On Sheet. It was when the train arrived at SOS for ships has no words that it is short for. It picked because it was easy to key and wouldn't be confused with any other messages or words. Richard
The original OS was for On Sheet. It was when the train arrived at
wjstixThanks for confirming what I said earlier. I've seen several references to OS originally meaning "On Sheet", nothing for any other meaning.
There is no official meaning for OS. I have been told by the dispatchers it mean Out of Station. There are a bunch of other meanings. For example in the modern CTC world, we called it an "Occupancy Section".
Since there is no "official" definition in any rule book, any definition is valid, it really doesn't matter, what's important is the practical meaning, that is a train has departed or passed.
Personally the more I read about it, the more I think it doesn't mean anything, its really just the shortest (ie fastest) two letter combination (dot dot dot dot dot) you can send in telegraph code for the most common telegraph message. Just like 19 and 31 really don't mean anything in train orders, that's just the codes they chose.
dehusman wjstix Thanks for confirming what I said earlier. I've seen several references to OS originally meaning "On Sheet", nothing for any other meaning. There is no official meaning for OS. I have been told by the dispatchers it mean Out of Station. There are a bunch of other meanings. For example in the modern CTC world, we called it an "Occupancy Section". Since there is no "official" definition in any rule book, any definition is valid, it really doesn't matter, what's important is the practical meaning, that is a train has departed or passed. Personally the more I read about it, the more I think it doesn't mean anything, its really just the shortest (ie fastest) two letter combination (dot dot dot dot dot) you can send in telegraph code for the most common telegraph message. Just like 19 and 31 really don't mean anything in train orders, that's just the codes they chose.
wjstix Thanks for confirming what I said earlier. I've seen several references to OS originally meaning "On Sheet", nothing for any other meaning.
"Dot (space) dot / dot dot dot." Two dots with no space is an "I" in American Morse. There are a few other characters that also use a short space in the sequence.
Using "OS" wasn't just used by telegraph. Operators using dispatcher's phones would say "OS (station)" when calling the dispatcher to make a report.