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Devious Diesel the Mean Engine
Thomas & Friends character
First appearance Duck and the Diesel Engine (1958)
Created by Rev. W. Awdry
Voiced by UK:
  • Kerry Shale


  • Michael Brandon (2010-2012)
  • Martin Sherman (2013-2015)
  • Kerry Shale (2015-present)


  • Rob Rackstraw (Learn with Thomas)
Gender Male
Nationality British English

Derek "Devious Diesel" the Mean Engine is a fictional anthropomorphic British Rail Class 08 diesel shunting locomotive from The Railway Series books, Duck and the Diesel Engine and Thomas and the Evil Diesel, and serves as the main antagonist in the television series, Thomas & Friends. In both the Railway Series and the television series he is the first diesel locomotive character to be introduced.

Diesel in the Railway Series

When Diesel came on trial to the North Western Railway, 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, and despite Duck apologising for the trucks being rude to him, Diesel blamed Duck for not helping him and making the trucks laugh at him. He then attempted to seek revenge on Duck by spreading rumors to the trucks by calling Gordon, a “Galloping Sausage”, James, “Rusty Red Scrap Iron”, and Henry, “Old Square Wheels”, and laid it all on Duck.

When the three engines heard about it, they accused Duck and refused to let him into the sheds. However, The Fat Controller became aware of Diesel's antics when he tried to tell lies about Henry, and immediately kicked him out in disgrace. His antics left a bad impression on the Sodor engines, and as a result rude Diesels were never welcome and some engines (particularly James) remained heavily prejudiced about Diesel Engines even after the others began accepting them.

Diesel in the television series

Diesel reprises his role from The Railway Series book Duck and the Diesel Engine in Series 2. He later returned in the Series 3 episode "Diesel Does It Again", when Duck and Percy needed help at Knapford Harbour. He proved to be just as troublesome as ever and was kicked out after shoving a load of China Clay Trucks into the water and bumping into Percy. In "The World's Strongest Engine" (Series 6), when Henry had an accident with some trucks, Diesel was brought back to help out with his goods work, but was again sent away in disgrace, after attempting his worth at being stronger than Henry, resulting in falling in a barge.

Since Season 7, Diesel has not had any form of acknowledgment that he belonged to the Other Railway and has remained on the North Western Railway ever since. Recent media also shows him a lot less inclined to prove diesel traction to be superior, and his character was largely rewritten to be more arrogant and self to other engines, even other diesels. He mainly picks on more naive and kinder engines, but his trickery is always found out in the end, leading to his inevitable comeuppance.

He appeared in feature length specials including: Calling All Engines!, The Great Discovery, Hero of the Rails, Misty Island Rescue, Day of the Diesels, Blue Mountain Mystery, King of the Railway, Sodor's Legend of the Lost Treasure, Thomas & Friends: The Great Race|The Great Race, Journey Beyond Sodor, and Big World! Big Adventures!.

Voice actors

  • Kerry Shale (UK; Season 13 onwards, US; Season 19 onwards)
  • Michael Brandon (US; Season 13-Blue Mountain Mystery)
  • Martin Sherman (US; King of the Railway-Season 18)
  • Rob Rackstraw (Learn with Thomas)
  • Daisuke Gōri (Japan; Season 2–8, excluding Season 6)
  • Hisao Egawa (Japan; Season 6 only)
  • Ken Sanders (Japan; Calling All Engines! onwards)
  • Shinichi Ishihara (Japan; The Great Race singing voice)