Thomas and friends Wiki
Den the Dieselworks Engine
  • Gender: Male
  • Stationed: Sodor Dieselworks
  • Designer: Rolls Royce
  • Builder: Rolls Royce
  • Configuration: 0-4-0

Den runs the Sodor Dieselworks with Dart.


Den is a diesel who runs the Dieselworks… when Diesel 10 is not around. While he isn't devious, he is still a diesel. Den is a hard worker and popular among the diesels. He is very thoughtful and thinks hard before he speaks. When Den does speak it is very slowly. This gives the appearance that he may be a little slow, but nothing could be further from the truth. Engines can wait a long time for Den to give his insight, but it is worth the wait![1]

In Day of the Diesels, Den and Dart take Percy to the back shed of the Dieselworks while Thomas, Diesel 10, and the other Diesels take over the Steamworks.

In the fifteenth series, he was classified as a weather reporter engine along with Dart. Den later was so mad over Diesel 10 being so evil that he turned evil himself and wanted all diesels scrapped for good. Can Den be turned good again? Well we'll soon find out in a new Thomas movie.


Den has a tendency to speak very slowly, and will often be heard saying, “What I mean to say is...” before Dart interrupts and does his talking for him. However, Den is a deep thinker and a very knowledgeable Diesel, who is a true asset to the Fat Controller’s Dieselworks.



Den is based on a Rolls Royce Sentinel Diesel-Hydraulic 0-4-0.

Voice Actor

  • Keith Wickham (UK/US; Day of the Diesels onwards)


  • Den is featured on the Dieselworks' logo.

59 Engines | 53 Rolling Stock | 5 Non-Rail Vehicles | 8 People | 15 Lines | 17 Former