Flynn is a fire engine who is part of the Search and Rescue Team.
Flynn worked with Belle on the mainland before they came to Sodor. Belle suggested to the Fat Controller that Flynn be brought to Sodor to help her fight fires. Flynn had instantly become popular with the engines on Sodor. Later on, Flynn and Belle helped Percy save Thomas and Kevin from Den and Dart at the Sodor Dieselworks. Flynn also used his ladder to assist welders during the restoration of the Dieselworks.
Flynn usually runs on the rails despite being a road and rail vehicle. Once, he went on the roads and found himself wobbling all over the place, so he returned to the rails. However, after putting out a fire at a farmhouse, he regained his confidence in using the roads and was able to help Bertie and Butch.
Later, some railway inspectors questioned wether the Fat Controller really needed two fire engines. Since Belle beat him to emergencies twice in a row, Flynn decided that he wasn't useful and sulked in his shed while Belle kept guard at a fireworks display at Ulfstead Castle. At the rescue centre, Butch arrived, telling Flynn that there was a fire at Brendam Docks. Flynn puts the fire out, knowing now that Sodor really does need two fire engines.
Flynn is a "really red fire engine" who fights fires on Sodor and is part of the Sodor Search and Rescue team. He has both tyres and flanged wheels, meaning that he is capable of running on roads and on rails. Flynn is fast, fearless, and ready to fight any fire. He is popular with the engines and held in high regard all over Sodor, but his overly-enthusiastic bravado can lead to not listening to instructions amidst his racing about and result in him making mistakes. He can also be self-conscious about maintaining his fire-fighting hero status. Nevertheless, Belle and the rest of the Search and Rescue team are often there to support him and keep him on course. And, at the end of the day, Flynn always has it in him to prove that he is always ready to rescue, and is a really useful hero.
- In several books, Flynn is depicted with blue wheel arches.
- Between seasons 15 and 16, Flynn's water cannons were operated mechanically. However since the seventeenth season, his cannons have needed to be pointed at a fire by the aid of the fire fighters, more accurately reflecting the operations of his basis.
- Flynn along with Belle are also best friends with Mr. Carrot Cake and Mrs. Cup Cake.