Diesel is a black diesel engine. He is the First Main Antagonist of the Show, also the secondary antagonist of the Series 2, but a Minor antagonist in Calling all Engines, Day of the Diesels & King of the Railway, and the Main Antagonist in Blue Mountain Mystery.
Diesel believes that steamies are no match for diesels. Oily, scheming and ever ready to stir up trouble in the shed, Diesel's characteristic smirk is a sure sign that some steamie, somewhere is in for a bit of trouble. However, given a chance, Diesel wants to show that he's a Really Useful Engine too!
When Diesel first came to Sodor in 1957, he began to be rude and troublesome to the steamies. Diesel then told the steamies a story about the time he saw a ghost train but Thomas didn't believe Diesel when Percy was to collect a bag of flour for the mill, Diesel knew that this was his chance to give Percy a fright so he blew his horn pretending to be a ghost Percy was so scared he jumped in surprise and the bag of flour flew in the air and landed on him Percy looked in a mirror and thought that what Diesel said was true and raced away but ran into Thomas Thomas thought Percy was a ghost and raced off. Diesel then told a lie about Thomas not wanting to be Percy's friend. Diesel is very devious.
Diesel is, in essence, the average pantomime villain. He is oily, malicious, devious, scheming and full of ideas to get revenge. It appears Diesel has a good side in him, but one would still have to look deep to find it.
Diesel is based on a BR Class 08 0-6-0. Over seventy members of this class survive today in preservation. They were in fact the most successful shunting engines in the world, with 996 of them built.
- Tim Curry (US and UK; Series 2-12
- Michael Brandon (US; thirteenth series - Blue Mountain Mystery only)
- Martin Sherman (US; King of the Railway - eighteenth series onwards)
- Jorge Ornelas (Mexico; thirteenth series onwards)
- Daisuke Gōri (Japan; second, third, seventh, and eighth series)
- Hisao Egawa (Japan; sixth series only)
- Ken Sanders (Japan; Calling All Engines! onwards)
- Paweł Galia (Poland; thirteenth series only)
- Janusz Wituch (Poland; Misty Island Rescue onwards)
- Christoffer Staib (Norway; thirteenth series - sixteenth series, excluding Day of the Diesels, Blue Mountain Mystery and King of the Railway)
- Helge Winther Larsen (Norway; Day of the Diesels onwards)
- Eberhard Haar (Germany; twelfth - fifteenth series)
- Martin May (Germany; Day of the Diesels onwards)
- Reinder van der Naalt (The Netherlands)
- Anibal Munhoz (Brazil)
- Jorge Teixeira (Spain)
- Michel Lasorne (France and French speaking Canada; eighth - twelfth series)
- Fabrice Trojani (France and French speaking Canada; thirteenth series onwards)
- According to the magazines, Diesel and Bulgy are good friends.
- In season fourteen and parts of series fifteen, Diesel had a different horn sound.
- Diesel's siderods were originally silver, but were changed to black in the sixth series.
- In some merchandise lines he is referred to as "Devious Diesel".
- Diesel's Shocked was never been used in series 2.