what the the letters os and pcs mean
“os”–when every station had an operator, the operator was required to note the time(s) of each train that went by or stopped at his station on a trainsheet as well as report it to the dispatcher, who noted it on his trainsheet. “OS” has been taken to mean that the information was entered on the train sheet.
Sorry, but I am cannot think what “pcs” means; at the moment I do not recall having heard of it, but I may be suffering from a senior moment.
You ask about “pcs”, but the title of the thread is “psc”, so I’m not sure which one you mean. Sometimes states have Public Service Commissions (PSC) which sometimes get involved in railroads or rail transit.
Depending on what terminology/convention the railroad engineering department uses, PSC/PCS can be where the simple circular curve meets the spiral curve in a main track curve. Where is the original poster seeing the accronym used? (mechanical term? signal term? operating term? engineering term?))
OS was the telegraph call the operator sent to signal the dispatcher he wanted to make the train report. It held over into the telephone era. Depending on who you ask, OS came from “On Sheet” meaning the time(s) written down on the operator’s station record or “Out of Station,” the time the rear of the train past the train order signal/office. (Personally, I fall into the “On Sheet” camp, You can OS a train in, out or by a station. If you’re OSing a train in, it certainly wouldn’t yet be out of the station.)
An example of how an operator would OS a train that didn’t stop by telephone:
Operator, “OS Marengo.”
Dispatcher answering, “OS Marengo.”
Operator, “Extra 4508 West by at 1:50pm, OK north side.”
The OK part was something the railroad I was familiar with (Rock Island) had their operators do. That is, report the condition of the train on the side they inspected as it passed.
It also can mean the part of a control point where the CTC/interlocking machine can definitely pinpoint the location of a train/engine. That’s why some might say OS means “Over Switch.”
PCS is the Pneumatic Control Switch on a diesel locomotive. When opened, by a penalty air brake application or emegency application (initiated by the crew or from a break in the air line) it reduces the load to idle. You have to stop, place the automatic brake valve into either suppression or emergency (depending on what opened the PCS) and it should reset after a couple minutes. I’ve also seen it called the Power Control Switch or Power Cut-off Switch, but it’s the same thing.
Jeff
I’m not sure here. The original poster did not provide ANY sort of context for where he’s seen/heard these terms. Since we have no idea of the context of the question, the above responses may not even be answering the correct question.