NKP 765 is a preserved steam locomotive built for the Nickel Plate Road and now operated for excursions, making its whistle familiar to railfans who follow mainline steam tours. Recordings of its distinctive blast circulate widely in train videos, documentaries, and sound libraries, where listeners recognise it as the sound of a working heritage locomotive rather than a generic effect. It remains popular because it instantly signals rail travel, history, and large-scale machinery, giving creators an authentic audio cue that needs no explanation.