'Signalman' definitions:

Definition of 'signalman'

From: WordNet
noun
A railroad employee in charge of signals and point in a railroad yard

Definition of 'Signalman'

From: GCIDE
  • Signalman \Sig"nal*man\, n.; pl. -men. 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. [1913 Webster]