Tidmouth Tunnel

The Castle Tunnel is a tunnel on the main line. It first appeared in the third season and was last seen in Calling All Engines!. It was originally on the Little Western, but it seemed to be moved to the main line in later seasons. Although never mentioned by name in an episode, it was first named in a learning segment.

Trivia

 * James once used this tunnel to smoke bees off his boiler when they would not leave him alone.