Thomas the Tank Engine Wiki
For other uses, see Diesel (disambiguation).

― Diesel's catchphrase

Diesel, as his name implies, is a black diesel engine who works on the North Western Railway.


Diesel is portrayed as one of Thomas' best friends. He is Thomas' competitive friend, always trying to one-up Thomas, and inadvertently causes trouble for everyone in his quest to be "the real Number One Engine." However, he does still retain some of his original personality, like trying to sabotage others in order to win a race. But despite this, he still has his limits when it comes to sportsmanship, especially after he witnessed his favorite racers, Farona and Frederico try and sabotage Thomas and Kana's chance at winning the Sodor Cup.

Technical Details


Diesel is based on a British Rail (BR) Class 08 diesel-electric shunter. In the real world, BR Class 08s were in fact the most successful shunting engines in the world with 996 of them built. Over seventy of them are preserved by heritage railways, such as the Dean Forest Railway and museums, such as the National Railway Museum. Around one-hundred BR Class 08s also remain in service on the national rail network.


Diesel is painted black with a dark purple stripe along each side and dark purple toolboxes and wheels. His valences and running board are also dark purple, while his bufferbeams are red.

During Race for the Sodor Cup, Diesel briefly wears a special livery in support of Farona and Frederico which is similar to his normal livery, however with a few notable differences. Namely, his running board and the stripe along his side are yellow, with an additional orange stripe in the middle and a yellow box under his face. After witnessing them cheat in an attempt to preserve their chances at winning, Diesel reverted back to his normal livery after Kana and Thomas crossed the gap.


Thomas & Friends: All Engines Go




Audio Files


First used Last used Sound Effect
A Thomas Promise Active

In the 2023 update of Go Go Thomas, Diesel uses his Misty Island Rescue horn sound and Mavis' horn sound in the original series.

Only used Sound Effect
Go Go Thomas! (video game)


  • In an early version of the script for A Thomas Promise used for auditions in January 2020, Diesel is renamed Joey, in order to keep the series a secret.[4]