The Caboose Who Got Loose tells the story of Katy Caboose, a caboose who is tired of being dragged around at the end of the train by the Engine. She dreams of being part of the beautiful sceneries she passes during her trips, but she cannot because she is always on the move. One day, when the engine is pulling the train up a steep mountain grade, the caboose is jolted loose from the train and flies back down the track towards a turn. Upon arriving at the turn, she has too much speed and she flies into the air off the track. Luckily she gets wedged between two trees, and she spends the rest of her days happy living in a beautiful place.