Some mimics were so good it was hard to tell the difference between an imitation of a train whistle and the real thing

CREDIT: "Great Northern Train, Four Miles West of Minot, North Dakota" 1912?. The Northern Great Plains, 1880-1920: Photographs from the Fred Hultstrand and F.A. Pazandak Photograph Collections from North Dakota State University, Library of Congress/Ameritech collections.