Thomas and Stepney is the sixteenth episode ever made in Season 4.
Thomas is shocked to learn that there is an engine with a branch line as famous as his and that the engine might visit. The engine, Stepney, has gotten bored with the Bluebell Railway and is delighted to discover he has been invited to visit the North Western Railway. When Thomas hears the news, he is jealous and refuses to meet Stepney, but the others welcome him and he works with Duck happily all day. When it is time for Thomas' last train, he is furious to be shunted to let another train pass, and amazed to find Stepney pulling it. Thomas grumbles next morning, but Stepney explains the situation and flatters Thomas, who proceeds to tell Stepney about his branch line.
- While the engines wait for Stepney, a tar wagon, perched on another tar wagon, is visible behind Gordon and Henry.