Diesel is a shunting diesel on the NWR. He currently does odd jobs around the island and shunts in the yards.
Diesel was built in Darlington Works in 1957 and on that same year he was sent to Sodor to shunt around the yards at Tidmouth. Duck was told to show Diesel around by The Fat Controller, Duck was not impressed of Diesel's revoltionary talk and told him to collect his The Trucks. As a result Diesel became a laughing stock in front of the trucks after trying to pull some old ones out of the siding and failing spectaculary. Diesel hated Duck and made a cunning plan, He was going to tell lies about the pannier tank and soon The big engines exclude Duck from the sheds and The Fat Controller had no choice but to send Duck to Edward's station, Diesel (who in the sheds at the time) smirked with delight as Duck puffed away.
Diesel soon became too big for his own buffers and got sent away in disgrace by The Fat Controller after telling lies about Henry. Diesel was sent away again after causing trouble at the harbour with some trucks full of china clay and he had pushed them into the sea!
Later Diesel told D261 about how he has learn from his past mistakes and to think before he acts in the future. The big green diesel just sniffed and rolled away.
Diesel is sneaky, devious, cunning and full of ideas to get revenge on an engine who may have teased or embraced him in the past. Though Diesel has now acted his age and can give some helpful advice to diesels that may have got into trouble on there time on Sodor.