Den

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

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

In the fifteenth series, he, Dart and Diesel tried to find a Christmas tree for the Dieselworks whilst in competition with Thomas. Den later teased Flynn for spraying the Fat Controller and Gordon.

In the sixteenth series, he and Dart helped Thomas fix Ol' Wheezy and repaired Gordon's bufferbeam.

In the seventeenth series, Den (along with Dart) help fixed a sputter in Salty's engine.

In the eighteenth series, Den, Dart, Sidney and Diesel hid from Paxton, causing Paxton to search for them.

In the nineteenth series, he was sent to the quarry as a replacement for Mavis while she was at the Dieselworks. Initially, Den struggled with the troublesome trucks. But after some encouragement from Toby and Henrietta, he toughened up and finished his job. When Mavis came back, Den went back to the Dieselworks.

In The Great Race, Den, Dart and Paxton were part of Diesel's plot to be taken to The Great Railway Show. Diesel had the three put under crates in a large train, making them resemble vans. When the Fat Controller was in the final stages of choosing who would go to the show, Diesel would then honk his horn to signal the three to start pushing, making it look as if Diesel was moving the train by himself (whereas the other three diesels would actually be doing most of the work) which Diesel hoped would convince the Fat Controller to take him to the show. The day before the show, Diesel refused to move his train from blocking all ways in and out of the yard, leading Thomas - who was in a hurry to demonstrate his shunting skills to convince the Fat Controller to enter him in the shunting competition - to move Diesel's train himself. When he whistled after a shunter coupled him up, the diesels mistook the tank engine's whistle as Diesel's horn and started pushing the train as they were instructed to. Thomas was surprised at the train pushing him and Diesel was horrified, thinking Thomas was pulling the train, realising his chance would be ruined. Though Sir Topham Hatt was impressed with the heavy train Thomas was "pulling", Thomas then collided with Norman at a set of points, losing his left buffer and ruining his chance to enter the show as well. Later, Diesel confronted the three and nearly forced Dart off the Dieselworks turntable. Instead, he made Dart bump into a button, sending a crate down on Diesel. Diesel later escaped to Brendam Docks and the three continued to hunt him down, only for Cranky to load him onto a ship bound for the Mainland.

After the workload at Brendam Docks got quadrupled thanks to Salty falling in the sea, Den was to be sent in the dockside diesel's place. But the slippery seaweed Salty dragged with him caused Den to slip out of control and set off a series of events that ended up incapacitating most of Sodor's diesels. Although they failed to fix the door controls in time, the mess at the docks was cleared thanks to the Steam Team.

Personality
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 and 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, 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.

Basis
Den is based on a Rolls Royce Class 4DH Sentinel diesel-hydraulic 0-4-0. These engines were built to replace Sentinel's steam line for use in various industrial shunting roles. Larger 0-6-0 and 0-8-0 variants were also produced. Several engines of this type are preserved, including one at the National Railway Museum and another at the Bluebell Railway.

Livery
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.

Appearances
 Television Series= {{Scroll box|

Thomas & Friends

 * Series 15 - Stop That Bus!, Stuck on You , Tree Trouble and Fiery Flynn
 * Series 16 - Ol' Wheezy Wobbles, Thomas Toots the Crows and Bust My Buffers!
 * Series 17 - Away From the Sea
 * Series 18 - Disappearing Diesels
 * Series 19 - Den and Dart
 * Series 21 - Springtime for Diesel, Dowager Hatt's Busy Day, The Big Freeze and Daisy's Perfect Christmas
 * Series 23 - Diesel Do Right, Steam Team to the Rescue and Diesel Glows Away

Specials

 * 2011 - Day of the Diesels
 * 2016 - The Great Race
 * 2017 - Journey Beyond Sodor

Music Videos

 * Day of the Diesels - Day of the Diesels
 * Series 17 - On a Journey Today
 * Thomas' YouTube World Tour - Navigation
 * Series 19 - Engine Roll Call
 * The Great Race - I'm Full of Surprises
 * Journey Beyond Sodor - I Want to Go Home
 * Series 21 - Set Friendship in Motion and Trying
 * Series 22 - Engine Roll Call and All the Girls Around the World

Videos
}}
 * 2014 - Welcome to the Island of Sodor Logan!
 * 2015 - A Friendly Farewell
 * -|Other Media=

Magazine Stories

 * 2012 - Ol' Wheezy Wobbles and Thomas Toots the Crows
 * 2014 - Salty's New Friend, Wobbly Ol' Wheezy and Leaves on the Line!
 * 2015 - Bust My Buffers!
 * 2016 - Thomas Toots the Crows
 * 2017 - Den and Dart

Official Description
2011-2021= From Official Media:

Trivia

 * In the nineteenth series, Den gained a standard tail lamp, despite already having two the same design as his front lamps.

Merchandise

 * Wooden Railway
 * Take-n-Play
 * Adventures
 * TrackMaster
 * Mega Bloks
 * Capsule Plarail
 * Pocket Fantasy
 * Capsule Collection

Den Den דֶן デン Trach Ден 丹恩