The melody comes from Thomas the Tank Engine, the British children's television series about a small blue locomotive and his friends on the Island of Sodor. Its cheerful theme has been familiar to generations of viewers, which is why distorted edits work so well online. Bass-boosted versions began circulating as meme audio, where the wholesome tune is turned up until it sounds like a crash itself. That contrast keeps it popular for reaction videos, gaming clips and short-form edits, especially whenever something goes suddenly and spectacularly wrong.