Green’s Dictionary of Slang

(US) orig. of a town, small, insignificant; thus whistlestop tour n., a tour that passes quickly through many small towns, whether lit. or fig.

1952		W.R. Burnett Little Men, Big World 144: That’s a big organization. Not like us, Arky. We are strictly whistle-stop.
1952		Lait & Mortimer USA Confidential 8: This Alabama whistle-stop kid who had never worn shoes until she was sixteen.
1999		Guardian 13 Mar. 🌐 Mr Schroder is preparing for a whistlestop tour of EU capitals to drum up support for his Agenda 2000.
2000		C. Cook Robbers (2001) 272: Up through old sawmill ghost towns and whistlestop junctions.
2009		Guardian 21 Feb. 🌐 Broken Glass is a whistlestop tour of French literature and civilisation.