After complaining of job dissatisfaction, Puff (a caboose) gets to trade positions with Huff (the engine) for a day. But soon enough, Puff realizes he is better designed for the job he is used to. Soft illustrations and brief thoughts throughout make this a clear and manageable read for the very young. Every day, Huff pulls the train and Puff pushes the train, but Puff wants a turn in front! The pals' adventures are perfect for beginning readers.