The line comes from Thomas and the Magic Railroad, the 2000 live-action Thomas the Tank Engine film, where it is shouted by Mr. Conductor Junior, played by Michael E. Rodgers. In the film Junior is the clumsy cousin of Alec Baldwin's Mr. Conductor and is known for panicked, over-the-top delivery. The isolated shout later circulated on soundboards and in short edits separate from the scene, kept alive by nostalgia for the film and by how well the drawn-out delivery works as a standalone joke about determination.