Den is a big diesel-hydraulic engine who runs the Vicarstown Dieselworks with his assistant, Dart.


Den was purchased to help run the newly-built dieselworks at Vicarstown with his companion, Dart. The two diesels worked well there together fixing broken diesels and electric engines until one day, the dieselworks started to become less occupied and was eventually left to rot and forgotten about. Den and Dart had also been forgotten and the two diesels were left stranded at the dieselworks for the remainder of that year, along with some other diesels; Diesel 10, Paxton, Norman and Sidney.

A year later when Percy found the dieselworks on accident, Den, along with the other diesels, were quick to greet him. When the diesels went to take over the steamworks, Den and Dart stayed and took Thomas to the back shed, preventing both him and Kevin from leaving the dieselworks.


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diesels for fixing them with a whisk of his wheels, even if his tools may be old and shoddy and his machinery may be outdated.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 trustworthy and authoritative, 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 Vicarstown Dieselworks logo on each side of his cab.


North Western Railway
ThomasEdwardHenryGordonJamesPercyTobyDuckDonald and DouglasOliverBill and BenDaisyBoCoBearNeilHarveyEmilyFergusArthurMurdochMollyNevilleRosieWhiffStanleyHankFloraVictorCharlieBash and DashFerdinandScruffBellePorterTimothyMarionLoganGlynnRyanGeoffreyDieselMavisDerekDiesel 10'Arry and BertSaltyDennisDenDartSidneyPaxtonNormanPhilipFlynnWinstonStaffordDustin