Thomas Made up Characters and Episodes Wiki
Thomas Made up Characters and Episodes Wiki

Based on:

Rolls Royce Sentinel Diesel-Hydraulic 0-4-0


Rolls Royce Sentinel


Rolls Royce Sentinel



Den is a diesel in charge of the Dieselworks, with Dart helping him. In the Gender Bent Universe, his female counterpart is Deni.


He was brought to help with moving parts around the Dieselworks. He is a slow thinker, usually leading to Dart completing or correcting his statements. However, he is a hard worker, and usually keeps Dart in order.


Den is the Diesel engine who runs the Vicarstown Dieselworks, repairing other Diesels. He is stately and deeply pensive. He tries to make sure everything he says is deeply considered, can often be heard muttering "what I mean to say is...", and can tend to over-think. He may come across as a little slow, but nothing could be further from the truth. He is rather astute and likes to take into account as much as he can with regards to a problem. Although he is not a worrier, he may tend to be on the fence about taking particular action over a matter before making a calculated, informed decision that will be worth the wait. Sometimes though, Dart, his assistant at the Dieselworks, can tell what he is thinking and cut to the chase a little quicker for the benefit of the other engines, which is why they support each other so well as a team. Den is a hard worker and is popular and well respected among the Diesels for fixing them with a whisk of his wheels, even if his tools may be old and shoddy and his machinery may be outdated. Although he is not devious, Den may have the occasional chuckle at an engine's expense.


Den is painted slate grey and orange with cream lining. His buffer beams are painted with orange and black wasp stripes. He has the Sodor Dieselworks logo on each side of his cab.

In Thomas the Slender Engine

Den inhabits Vicarstown Dieselworks (Dusk) with Dart.


Adventures on Rails


Sodor Adventures

  • Season 1 - The Crashing Kipper and Dave the Diesel (cameo)
  • Season 2 - Frozen PointsThe Peel Godred Branch Line, Dave's Scary Tale, and Diesel Day (does not speak)
  • Season 3 - HomesicknessSidney Helps Out, Bill, Ben and Derek, Derek Comes Home, Pompous Popularity (mentioned). and Jonathon and Stafford
  • Season 4 - Saved by the Belle
  • Season 5 - Silver Steam
  • Season 6 - The New Diesel Fuel
  • Season 7 - Toby's Snowplough (cameo) and Salty and the Small Engines


  • Thomas and Percy
  • The Curse of the Flying Kipper

The Adventures on Sodor

The Many Adventures on the Island of Sodor


  • In Adventures on Rails, he was originally meant to be introduced with Dart in the seventeenth season.