Porky is the engineer on the most pathetic train in the fleet. After some routine episodes (using pepper to get the engine to sneeze itself up a hill, chasing a cow off the tracks, only to discover too late that it's been replaced by a very angry bull), Porky gets word that he's going to be replaced by the new streamlined Silver Fish. He insults it under his breath, but the Silver Fish engineer hears and challenges him to a race. The angry bull catapults Porky to victory.
—Jon Reeves <jreeves@imdb.com>