Model Railroader magazine for January 2007 has a new article on the back inside page on “Operations”. This particular article is about “OSing”. Its history and what the term means. Looks like a pretty good start for a series.
“OSing” according to MR means “On Sheet” as to the train has passed this location and is now on my sheet of trains going passed this location. In the past, I was always under the opinoin that “OS” meant “On Station”, which was a statement that never made quite as much sense. The most interesting statement to me was that the train was put on the sheet as the last car passed that location. “OS” being the telegraph code and then carrried forward as Station Agents moved to communication with the Dispatcher by telephone and then teletype.