Problem Passenger is a magazine story.
One morning, Thomas and Annie take some passengers to the Wildlife Park. They have great fun watching the animals. They see a tiger, which Thomas is sure can run faster than Gordon, and a kangaroo. Annie particularly likes the kangaroo because, like herself, she is carrying a passenger. They are so busy watching the animals that they do not notice a monkey climb on board. When Thomas and Annie return to the station, the monkey climbs onto Annie's roof. The monkey then runs along Annie's roof to Thomas' cab, where he blows the tank engine's whistle. No one is able to catch the monkey, so Thomas steams back to the Wildlife Park with the monkey sitting on Annie's roof. The monkey is soon safely back with his keeper, leaving Thomas glad that they do not have many passengers like him.
- Clarabel is missing from the story.