Thomas' Branch Line is Thomas' own line that he received after helping James following his accident.
Thomas' branch line starts from Knapford Junction where it connects with the Main Line. It then calls at Dryaw, Toryreck, Elsbridge, Maithwaite and Hackenbeck before terminating at Ffarquhar.
The branch carries passengers, quarry stone, farm produce, dairy products from St. Pedroc's Dairy in Elsbridge, general goods, and uranium from the mines. Some passenger trains work into Tidmouth.
Thomas takes passenger trains with Annie and Clarabel. Toby and Henrietta run trains to Anopha Quarry, where Mavis works. Percy runs the goods trains on the line. Daisy used to take passenger trains on the line before taking the passenger duties on the Arlesburgh-Harwick Branch Line.