Diesel 10 is a mean diesel locomotive with a claw he named 'Pinchy.'
A long time ago, Diesel 10 pursued Lady, an engine privately owned by Burnett Stone, and caused an accident. Years later, Diesel 10 arrived on Sodor (along with his two evil minions Splatter and Dodge) during the same time as Lady when she came to visit, and Diesel 10 decided to take out some of his own personal anguish from his past by destroying Lady. He chased her, along with Thomas, on a route that lead to a broken viaduct. However, he was to heavy and fell off. He was eventually rescued.