Thomas is a tank engine who lives on the Island of Sodor. He is engine No. 1 on the North Western Railway, and works on the branchline at Ffarquhar with Percy, Toby, Daisy and Mavis (loaned from the Ffarquhar Quarry Company)
Thomas was one of the first locomotives to arrive on the North Western Railway in 1914. Technically he is not the first locomotive to arrive though because there were a fair number of engines from the Furness Railway and the Midland Railway also loaned there for the war effort. After the war ended in 1919, the Fat Controller bought Thomas for use with another engine from the Furness Railway, Edward. Thomas was used as a shunting engine at Vicarstown until after a near miss he was moved to Wellsworth during World War II. This was a good call, because he witnessed the new engine James being pushed down the line by a rampanging train of Troublesome Trucks only to end up crashed in a cow's field. As his reward for rerailing him with the Breakdown Train (which happened to be in Wellsworth Yard at the time), Thomas was promoted to be the main operating engine on the Knapford branchline to Ffarquhar (formerly the Tidmouth, Knapford & Elsbridge Light Railway). He still runs the line today Percy, Toby, Daisy and Mavis (loaned from the Ffarquhar Quarry Company).