whistle stop, n. — Green’s Dictionary of Slang

whistle stop n.

[orig. railroad jargon whistlestop town, trains do not halt at such a town unless a passenger informs the conductor who then signals the fact by pulling on the signal cord and the engineer acknowledges the request by two whistles. The derog. sl. use led to the abandoning of the term by the railroads, who substituted flag stop or flag station to spare local feelings]

(US) a small town.

1934		Weseen Dict. Amer. Sl. 418: [General] Whistle Stop, a small town.
1947		N. Algren Neon Wilderness (1986) 48: Home had been a whistle stop called Dustland, in the Oklahoma sand hills.
1951		Kerouac On the Road (The Orig. Scroll) (2007) 192: The little Californian town – a whistle stop on the S.P.
1959		A. Zugsmith Beat Generation 57: The pair of strait-laced spinster aunts who raised him in the Midwest whistlestop.
1989		H. Rawson Dict. of Invective (1991) 306: Whistle-stop.
1992		B. Gifford Night People 177: Cuba, which was something less than a whistle-stop of a town.