|This article is about the castle tunnel. You may be looking for the South tunnel.
Tidmouth Tunnel is a tunnel on Duck's Branch Line between Tidmouth and Tidmouth Hault.
It first appeared in the third season; It returned in Tale of the Brave and later appeared in The Adventure Begins and has made infrequent appearances since.
In the television series, this is where James once tried smoking bees off his boiler.
- The number of tracks leading through the tunnel changes between one to three tracks on many occasions. Since Tale of the Brave, there have been two tracks.
- The Castlelated Tunnel is a modified version of this tunnel.