Thomas the Tank Engine Wikia

Diesel is a black diesel engine who originates from the Other Railway, and is the first known standard-gauge diesel to ever arrive on Sodor.


When Diesel visited the North Western Region on trial from British Railways, Duck was asked to show him around. Duck was unimpressed by Diesel's claims of being "revolutionary" and left him to his own devices. As a result, Diesel was made into a laughing stock by the trucks for trying to pull some rusty old trucks and failing spectacularly.[1] Diesel then blamed Duck for not helping him and swore a vendetta plan; he spread rumours that Duck had given the big engines rude nicknames, which led to Duck being sent to Wellsworth pending an inquiry into the matter.[2] Diesel meanwhile got too big for his buffers and started telling lies about Henry, but he was found out and sent home in disgrace.[3] His visit was brief but impactful, as his behaviour left a bad impression about diesels to the Sodor engines.

Several years later, Diesel was brought back to help on Thomas' Branch Line whilst Percy was being repaired. Diesel tried to win Thomas and Toby over, without success and after he destroyed an old truck, he was to be sent away. However, on his day of departure, Clarabel slipped on oily rails left by Daisy and came off at some points near Dryaw. Diesel - realising that Thomas was blocking his only way home - went to the rescue. Clarabel put in a good word for him, and Diesel - although he returned to the Other Railway - has since always been welcome on Sodor.[4]


Diesel is, in essence, the average pantomime villain. He is oily, malicious, devious, scheming and full of ideas to get revenge. He views himself and any other diesel as highly above the steam engines and believes that all diesels are "revolutionary".

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.

Aside from Diesel himself, two other BR Class 08s also appear in The Railway Series.


Diesel is painted in the BR mixed-traffic black livery, which was the standard livery for shunting engines from 1948 until the mid-1960s. Diesel has unpainted silver siderods - unlike most BR black Class 08s, which had them painted red - indicating he was built by Darlington Works.



  • Diesel was the first diesel engine to be introduced in The Railway Series.
    • He was created when Eric Marriott, the editor of The Railway Series at the time, suggested that Awdry should introduce a diesel in order to keep the books up to date.


The Railway Series

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