The person standing in the tower above the Start/Finish Line who controls the race with a selection of flags.

The person standing on the tower above the Start/Finish Line who controls the race with a series of flags.

One who makes signals with a flag.

The official who signals the end of elapsed time in timed events.

an unofficial goal observer appointed to signal by waving a flag over the head if a goal is scored, or under the waist if no goal.

Usually, the brakeman assigned to duties at the rear end of the train.