Definitions for "Signalman"
A man whose business is to manage or display signals; especially, one employed in setting the signals by which railroad trains are run or warned.
The man who controls the signals and authorizes the movements of trains on running lines.
the train worker responsible for coordinating signal lights along a specific section of track.
Signalman is a DC Comics supervillain who usually fights Batman. He first appeared in Batman #112 (December 1957).