On sheet refers to the dispatcher's train sheet, the log of each train's passing times. In territory without track circuits, crews OS a point by radio so the dispatcher knows where they are; in CTC the system OSes trains automatically as they pass through a controlled point. The short track section through a controlled point is the OS section on many railroads.
Dispatcher, 4421 east, OS Ellis at 0412, we're by the east switch and the whole train's clear.
Also heard as
- on sheet
- OSing
Related terms
DS
Dispatcher, as said on the radio: the person who controls train movements over a territory.
CTC
Centralized traffic control: signals and switches controlled remotely by a dispatcher who routes every train.
Track warrant
A written authority from the dispatcher, copied by radio, that lets a train occupy a set stretch of main track.
MP
Milepost: the numbered marker that fixes every location on a railroad by distance along the line.