The Arlesburgh-Harwick Branch Line is a branch line that runs from Arlesburgh Junction to Harwick. The line is run by Daisy who handles passengers and Ryan who handles the goods. When the line was constructed, it had to be diverted as part of the original track bed collapsed revealing a hidden cavern. It will be introduced in Sodor's Legend of the Lost Treasure.
- Arlesburgh Harbour
- Arlesburgh Yard
- Arlesburgh Yard Sheds
- Calles Cavern
- Winnie the Pooh, Ash, Princess Twilight, and their friends will visit this branchlike in Pooh's Adventures of Thomas & Friends: Sodor's Legends of The Lost Treasures.
- Brian Griffin will visit this branchline in Brian Griffin's Adventures of Thomas & Friends: Sodor's Legend of the Lost Treasure
- Ed, Edd, n Eddy will visit this branchline in Ed, Edd, n Eddy's Ed-ventures of Thomas & Friends: Sodor's Legend of the Lost Treasure