As a hero, he wants to try to prove himself Really Useful, but instead he usually acts more like a school yard bully and still hates steam engines, much to the annoyance to Thomas fans. It can be possible that Diesel is a permanent resident of Sir Topham Hatt's railway since Season 8. Diesel is based off a BR Class 08 Diesel Shunter, like 'Arry, Bert, Paxton, and Sidney.