Percy's Rainbow is a magazine story.
One Saturday, Percy puffs by the school. The Fat Controller had asked an artist to paint a picture on the school's wall. Suddenly, it starts raining. Because it's the weekend, the school is locked, so Percy offers to shelter all of the children and everyone else in his carriages. Percy decides to take them all on a tour whilst waiting for the rain to stop. Shortly, the children are delighted to see a bright rainbow in the sky and are disappointed when it fades away. Next, they arrive at Brendam Bay where they see another rainbow. Back at the Main Station, Percy told the Fat Controller what they saw, which gives him an idea. Later, he asks all of the children back to the school for a surprise. On the wall was a bright, colourful rainbow. Everybody is delighted.