Train horns are a staple of railway sound libraries and have been reused for decades in films, cartoons and online videos to signal an approaching locomotive. On soundboards, the clip is popular because it is instantly recognisable even without any visual context, and its long, sustained blast works as both a warning and a punchline. Editors favour it for pranks, reaction videos and gaming clips, where a single loud horn can break tension, announce a twist or turn an ordinary moment into something theatrical.