Minga, Prickle, and Granny are going on a train ride today. Unfortunately, the Blockheads think it'd be fun to lock the engineers in the men's room and send the train on a wild joy ride. Since the trains in Gumbyland bring their tracks with them wherever they go, the train can go crashing through houses and down streets, bringing chaos and destruction everywhere it goes. Naturally, Granny loves it. Things take an ugly turn when the train enters a book about the Rocky Mountains and gets on a track leading straight to a giant fall, but fortunately, Gumby has learned of the runaway train and he helicopters the engineers into the train to stop it.