Tram horns are a standard warning signal on streetcars and light rail vehicles, used to alert pedestrians and drivers when a tram is approaching or cannot stop quickly. Short recordings of that signal have circulated online as standalone sound effects for years, picked up by video editors who need a loud, public warning that listeners recognise instantly. Because the clip is under two seconds long, it fits neatly into memes, reaction videos, and city-themed edits, where a single blast can signal danger, impatience, or comic timing without any dialogue.