Main Page

This article is about 'the diesel engine'. You may be looking for 'the Story Library book'.

Dennis is a lazy, grey, 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 learned 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 diesel engines 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, possibly a part of the original script idea for Day of the Diesels.
  • Dennis had a total of six face masks, one of which was never shown on-screen.
  • Dennis was originally intended to return in Day of the Diesels, however, he was later dropped and replaced by Norman, who shares the same basis.[3]
  • 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

*Disclosure: Some of the links above are affiliate links, meaning, at no additional cost to you, Fandom will earn a commission if you click through and make a purchase. Community content is available under CC-BY-SA unless otherwise noted.

Fandom may earn an affiliate commission on sales made from links on this page.

Stream the best stories.

Fandom may earn an affiliate commission on sales made from links on this page.

Get Disney+