The Works Diesel rescued James after his injector failed, and managed to change James' opinion of diesels with his charismatic persona. He then brought the Christmas tree for Thomas from the Other Railway. In Gordon the High-Speed Engine, Donald mentions that there are other diesels at the works. The Works Diesel was later seen talking to Gordon at Barrow-in-Furness.
Although the Works Diesel has not spoken, he is described as being friendly and is impossible to not like - even James, who retained a hearty dislike of diesels, could not help but befriend him before the two had even reached the Works.
The Works Diesel is based on a BR Class 47 "Brush" Co-Co diesel locomotive.
The Works Diesel is painted in the British Rail "Rail Blue" livery with yellow warning panels. He lacks the BR logo and has a indiscernible number painted on his sides in white.
- Really Useful Engines - Triple-Header (mentioned)
- James and the Diesel Engines - Deep Freeze (does not speak)
- Gordon the High-Speed Engine - Fire Escape (mentioned)
- Henry and the Express - Out of Puff (cameo)
- Thomas and the Missing Christmas Tree (does not speak)
- Over 512 of the class was built from 1962–1968, 32 of these diesel engines are now preserved, while another 30 are still used on the national railway network.
- The Works diesel's number is unknown but it can be presumed that the his number could be fictional like the other diesels that appeared in Stepney The Bluebell Engine.