The whistle comes from Baggage Buster, a 1941 Walt Disney cartoon starring Goofy as a railway station baggage handler whose day descends into chaos. In the short, the whistle belongs to the steam locomotive at the station, and its bright, theatrical sound is typical of Disney animation of the era, when effects were exaggerated to match the on-screen slapstick. Fans later lifted the short clip for edits and soundboards, where it survives as a handy shorthand for old cartoon trains, departures and hurried arrivals.