Unlike meme clips tied to a single show or creator, a tram horn is a generic transport sound effect drawn from real city transit. Trams have used loud horns for decades to warn pedestrians and drivers at crossings, and recordings of that warning have long circulated in stock sound libraries for film, television and online video. On soundboards it is usually listed alongside other vehicle and street effects, where editors search for it by vehicle type rather than by a character or catchphrase. Its continued use comes from its instant recognisability as urban transport.