Duck the Great Western engine works very hard on the Island of Sodor and everything goes smoothly when he is around. He can keep the coaches quiet, the trucks behaving, and the passengers happy. He is also very proud of his Great Western heritage and talks endlessly about it, which irritates the larger engines who quickly grow tired of hearing about "the Great Western way".
One day, a visitor arrives in the shed. The Fat Controller introduces the new engine as Diesel, stating that he is going to be given a trial and charges Duck with showing him around and teaching him what to do. Diesel introduces himself before heaping compliments on Gordon, James, and Henry, who are in awe by his flattery. Duck, however, takes a dislike to Diesel's oily nature and shows him to the yard.
There it becomes apparent that Duck's dislike of Diesel is mutual as Duck orders Diesel to refer to the Fat Controller as "Sir Topham Hatt", before Diesel smugly tells Duck that he does not have to be taught what to do. As a diesel, he already knows everything and that diesels will always improve a yard, calling diesels revolutionary. Duck is not impressed with Diesel's boasting and orders him to arrange the trucks while he leaves to take Gordon's coaches to the station.
Diesel, eager for the chance to show off, quickly gets to work. However, he attempts to move the wrong trucks; some really old ones which have stiff joints and brakes. Duck arrives, and realises what is happening, but decides to let events play out, and watches with interest. When Diesel cannot move the trucks, he gets so forceful with the them that some of their brakes snap and the gear jams in the sleepers, causing several of the trucks to derail and overturn. Diesel still cannot move the remaining trucks and is forced to give up.
As Duck finally comes around carrying some other trucks, Diesel asks Duck why he did not tell him about this when he had gone through so much trouble. Duck replies that Diesel never asked him, and besides, he was having so much fun "revolutionising" the yard. Duck leaves happily, while Diesel fumes angrily.
Diesel is later forced to help clean up the mess, a duty that he hates especially as the trucks have started teasing and singing at him as he does. When the clean-up is over, Diesel, now unhappy with the trucks and with Duck, storms off back to the shed to sulk.
- Troublesome Trucks
- Sir Topham Hatt
- Percy (cameo)
- The first appearance is Diesel in the TV Series