Tidmouth Tunnel, also known as the Castle Tunnel, is a tunnel on Duck's Branch Line between Tidmouth and Tidmouth Hault.
It first appeared in the third season.
In the television series, this is where James once tried smoking bees off his boiler.
- Season 3 - Buzz, Buzz, All at Sea, Tender Engines (deleted scene), Oliver Owns Up and Percy, James and the Fruitful Day
- Season 7 - Emily's New Coaches, Bill, Ben and Fergus (deleted scene), Edward's Brass Band, James and the Queen of Sodor (stock footage), The Spotless Record, Snow Engine, Something Fishy and Best Dressed Engine
- Tidmouth Tunnel has had numerous modifications throughout the years:
- Season 7:
- The tunnels architecture changed.
- The lake became significantly smaller.
- The Castlelated Tunnel is a modified version of this tunnel.
* RWS only | ** T&F only
||Duck | Donald and Douglas | Oliver
||Alice and Mirabel* | Isabel and Dulcie* | Red Express Coaches** | Red Branch Line Coaches** | Toad | S.C. Ruffey | Fred Pelhay* | Rickety* | U.L.P.* | Ballast Trucks | Mail Vans**
||Bulgy | Bulgy's Friend | Algy***
||Tidmouth (Beach, Beach Village**, Harbour, Hault**, Hault Sheds**, Tunnel**, and Yard**) | Dilly's Pond | Workmen's Hut** | Three Tier Bridge** | Haultraugh (Bulgy's Bridge, Bulgy's Field) | Arlesburgh (Engine Sheds*, Harbour**, Trading Co.**, West)