Toby's Castle is a magazine story.
One evening, all of the engines are talking in the shed. Toby says that he would like to help build a castle. James scoffs and Toby explains that he could help by pulling trucks of bricks. James teases Toby and tells him that castles are made of stone, not bricks. Toby tells James that he and Henrietta could carry the workmen to the building site. James then tells Toby that it would be impossible since no one builds castles any more.
The next morning, the Fat Controller orders Toby and Henrietta to collect some schoolchildren and their teachers from their school to the seaside and then take them home again later on. Toby is delighted and he and Henrietta soon arrive at the seaside.
After a busy day's work at the quarry, Toby and Henrietta go back to the beach to collect the children and their teachers. The children have a lovely day by the sea and Toby can see that they have built some splendid sandcastles. The children then thank Toby for bringing them and helping to make their day.
That evening, the engines are all discussing their day. Toby is delighted to tell James about his day. He tells James that had gone to the beach and saw lots of splendid sandcastles - and he had helped to make them too.