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Dennis is a lazy diesel shunter. He has a twin named Norman.


Thomas & Friends

When Dennis was new to the railway, he tried to take advantage of Thomas by getting him to do all his work for him. He soon learnt his lesson when he reversed into a ditch. With Thomas' help, he was able to finish his work and promised to be a Really Useful Engine from then on.

In The Great Discovery, Dennis and a number of other diesels were waiting in the quarry yard upon hearing that Thomas had been found in the days leading up to the reopening of Great Waterton.


Dennis is considered to be a very lazy diesel who tries to take advantage of others and depend on them to do his work instead. Dennis will often create excuses to get out of work, but usually gets caught in his lies and always says sorry - but whether or not he means it is the question.

Technical Details


Dennis is based on No. 11001, a prototype Bulleid diesel built at Ashford Works, England in 1949 and scrapped in 1959. He also carries his basis' number. Norman is also a member of this class.


Dennis is painted two-tone grey with dark grey wheels, gearboxes, roof and front. The number "11001" is painted on his sides in white.


Voice Actors

Audio Files


First used Last used Sound Effect
Series 9 Series 9
Dennis' Horn


  • According to a magazine article, he lives at the Vicarstown Dieselworks with Diesel 10.
  • Dennis had a total of six face masks, one of which was never shown on-screen.
  • His horn sound was reused for Flynn in Steam Team to the Rescue.
  • Dennis' horn sound has been heard in Tractor Tom multiple times as that of main character Rev. 



* RWS only | ** T&F only | --- Dropped

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