A young child walked up to a man in a dark blue uniform, standing next to a north bound train waiting to depart the depot. The child asked, "Excuse me sir, can you tell me what time it is?"
The conductor pulled his pocket watch from his vest pocket, examined it for a few seconds, then told the child "It is 11:55." The child stood there, amazed with his large shiny watch. The conductor then added "the train will be leaving in ten minutes, just after the south bound fast mail train pulls into the depot."
A few minutes earlier the conductor had checked his pocket watch against the depot "standard clock," as had the engineer in the locomotive at the front of the train, they knew that the safety of the passengers depends on all train crews accurately knowing what time it is, according to railroad time.
As the new railroads were being built trains were typically operated on a single track, including those going in opposite directions, with sidings provided at intervals to allow trains to pass each other. Railroads operated using a timetable to avoid collisions between trains and to move trains efficiently over the railroad lines.
A timetable is a published schedule of the movement of trains which lists the trains, locations along the railroad line, and times at which certain events, such as arrivals and departures at a station or siding, are expected to take place. Most railroads specified a time interval to allow trains time to pull in and out of sidings and stations.