Pop Goes the Diesel

"Trucks are waiting in the Yard; Tacking them with ease'll, "Show the world what I can do," Gaily boasts the Diesel. In and out he creeps about, Like a big black weasel. When he pulls the wrong trucks out – Pop goes the Diesel!"

- Troublesome Trucks

Pop Goes the Diesel is the twelfth episode of the second season. It aired in the US on the Shining Time Station episodes, Promises, Promises and Yabba, Yabba, Yabba.

Plot
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, which quickly win them around to the newcomer. 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. Duck is not very happy about this and orders Diesel 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. When Diesel cannot move them, he tries getting very forceful with them. Duck arrives, and realises what is happening, but decides to let events play out. Diesel gets so frustrated with the trucks that he accidentally overturns some when their brakes snap. Diesel still cannot move the remaining trucks and is forced to give up.

Duck finally comes forward carrying some other trucks and Diesel asks Duck why he did not tell him about the others. Duck simply reminds Diesel that he was supposed to instantly improve the yard. Duck leaves happily, while Diesel fumes.

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. When the clean-up is over, Diesel, now unhappy with the trucks and with Duck, storms off back to the shed.

Characters

 * Henry
 * Gordon
 * James
 * Duck
 * Diesel
 * Sir Topham Hatt
 * Percy (cameo)

Locations

 * Tidmouth Sheds
 * Knapford Yards
 * Sodor Shipping Company
 * Brendam Warehouse

Trivia

 * This episode is based on the story of the same name from The Railway Series book, Duck and the Diesel Engine.
 * In Norway, this episode is called "Diesel Snarls and Snarls". In Germany, it is titled "Beautiful Rubbish, Mr. Diesel!". In the Netherlands it is named "Diesel Flops". The Croatian title is "Diesel Failed". The Italian name is "The Diesel Locomotive". In Japan, this episode is called "Here Comes Diesel". It is called "Diesel Locomotive Stays" in Finland. The Spanish title is "Diesel Gives the Note".
 * The title is a pun on the nursery rhyme, "Pop Goes the Weasel".

Goofs

 * In the scene where Duck is exactly side-on, a small space between the face and the model is visible.
 * Henry's tender is missing in the first shot featuring him.
 * When Duck passes James, Gordon, and Henry, there are only two tracks to the right of the water tower and it is not in line with the Sodor Shipping Company building. When Diesel and Duck arrive later on, there are three tracks to the right of the water tower and it is in line with the building.
 * Diesel follows Duck too quickly for the turntable to have turned to face him.
 * Gordon and Henry's eyes are wonky when Duck and Diesel leave.
 * When Duck and Diesel frown at each other Duck is missing his eyebrows. Duck is also missing eyebrows when Diesel first backs into the shed.
 * At the beginning of the scene in which Diesel passes through the Sodor Shipping Co., there is a truck directly behind him on the same track. This would have made it impossible for him to pass without shunting the truck.
 * Duck isn't in the siding when Diesel tries to pull the trucks.
 * Steam can be seen around Diesel when he was trying to move the trucks.
 * When the narrator says "Diesel lost patience", one of the trucks has a piece of hair on it.
 * When Diesel tries to push the trucks back he backs down onto the breakdown train, not the trucks. In the same scene, one of the buffer stops on the left is leaning over.
 * In one scene, there is not a truck in the siding that Duck is in before he goes to collect the other trucks. One appears in the siding during the trucks' song, then after it finishes there is not.
 * In the scene of Duck seeing Diesel after collecting the trucks, Diesel backs down to the trucks he had been struggling with - straight into them - then he comes forward a little so as to be directly in line with Duck. Last of all, when Duck leaves, he goes backwards suddenly before heading off.
 * After Duck leaves to get Gordon's coaches, there is still steam venting from the track.
 * Diesel clearly does not have a driver when he is on the turntable, but he somehow reverses into his shed.
 * In a rare picture, Diesel's siderods are crooked.
 * A brakevan should have been added to Diesel's train.