Porky is the engineer on Toots, his faithful old “Fifteenth Century Limited” train (a crack train; everything is cracked, including Porky), which is to be replaced by the modern streamliner “Silver Fish,” engineered by the villainous Dirty Diggs. They race each other. Porky’s train is too feeble to climb a mountain, so he sprinkles pepper in the engine so that it can sneeze its way up.