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This article is about the episode. You may be looking for the Philippine, Swedish or South African DVD.

“Is that all you can haul? Henry's loads are longer. Is that all you can haul? Henry must be stronger.”
―The Troublesome Trucks

The World's Strongest Engine is the eleventh episode of the sixth series.


Henry ends up having an accident pulling a goods train thanks to some Troublesome Trucks and is sent to the works to be mended, and the Fat Controller tells the engines that Diesel is the only spare engine available. The engines are not very happy about this, knowing how much trouble Diesel is. Percy and Thomas both hope that Henry is mended soon, claiming Henry moves more trucks than three diesels put together, while Gordon declares that trucks are no one's friends.

The next day, as Diesel is working at the docks, he brags to the trucks that the Fat Controller get rid of steam engines completely once he sees how good Diesel is at shunting trucks. The Troublesome Trucks suddenly have an idea; they begin to tease Diesel, saying how Henry can move more trucks than he can shunt. This makes Diesel cross, so he decides that he will push them all at the same time, claiming himself as the world's strongest engine.

"Grease and oil!"

Diesel arranges a line of twenty trucks and couples up to them, but unbeknownst to him, a shunter has put the brakes on the trucks. Despite that they already know about it, the trucks encourage Diesel to push them anyway. But with his efforts to move them, the trucks do not move, so he decides to pull them instead. As he pulls, the trucks sing at him, making Diesel very cross. He pulls even harder, but he pulls so hard that he breaks his coupling from the trucks and he runs out of control, falling off the quay and landing onto a barge containing flour bags. Diesel is disgusted and humiliated by the predicament, as all the trucks laugh at him.

Henry (who is now repaired) arrives at the docks with the Fat Controller, who is very cross with Diesel and sends him home in disgrace. He asks Henry to make up for lost time, and Henry reverses to the trucks. After the shunter releases the brakes, Henry pulls away from the docks, pulling the line of trucks easily, and the engines all cheer. Thomas and Percy agree that even trucks can be helpful to the engines sometimes, such as helping to get rid of Diesel.




  • S.S. Vienna from TUGS can be seen.
  • This episode may have been inspired by the 1997 magazine story, Showing Off.
  • Some shots of Diesel attempting to move the trucks are sped up.
  • Diesel's theme in this episode was released on Junior Campbell’s official YouTube channel.
    • Additionally, in the upload, there was a musical ditty intended to be played during the scene where the Troublesome Trucks say, “Push us all that’s the longest, push us all you’ll be the strongest!", but for unknown reasons it was muted in all versions.
  • This episode marks several things for Diesel:
    • The first time his siderods are black instead of silver.
    • His first individual speaking role since the third series episode, Tender Engines.
    • His first leading role since the third series episode, Diesel Does it Again.
    • His only appearance in the sixth series.
    • The first time his third series snarling face is used on-screen.
    • His second time trying to pull a line of trucks with the brakes on, the first being in Pop Goes the Diesel, his debut episode.
    • The last time he was sent away from Sodor. From the seventh series onwards, it has been reported that he permanently became one of The Fat Controller's engines on Sodor.
    • His last leading role as the main character in the Classic Series, and last overall leading role until the ninth series episode, Flour Power.
  • This is the second time the narrator says the phrase "confusion and delay," after Cranky Bugs. But it is the third time it was said overall, in the fifth series episode, Oliver's Find, it was said by a character.
  • The shot of Diesel bragging to himself when he arrives at the docks is shot in a 4:3 aspect ratio, as opposed to the 16:9 aspect ratio the rest of the episode was shot in.
  • In both English dubs, the recording of Diesel's shout "HELP!" as he falls off the quay was later used for Duncan later on in this series for the episode, Dunkin Duncan.
    • In addition, the final recording of "And he pulled" in both English dubs is repeated once before Diesel breaks the chain.
  • The pupils on the face for one salt van are actually pieces of tape.
  • In the book adaptation, Diesel and the Troublesome Trucks, it is said for Diesel to have crashed in Bulstrode the barge.
  • This episode marks Henry's only major role in the sixth series.
  • This episode marks the first appearance of the Sodor Slate Quarry in the television series.
  • The trucks sing rudely to Diesel in different tunes in the respective UK and US dubs.
  • This marks the last of a few things for the trucks:
    • The last episode to feature NER Vans with faces.
    • The last episode to feature Salt Vans with larger faces.
    • The last episode to feature Cattle Trucks with faces.


  • In the first scene, Clarabel is facing the wrong way.
  • Oliver and Duck have the same whistle sound.
  • One of the workmen who comes to rescue Henry is tilted.
  • At Tidmouth Sheds, the buffers behind Thomas are resting on top of the rails.
  • When Diesel pushes the trucks back, his side rods are going forwards.
  • In the close-up of Diesel going in between the trucks bragging to them, studio equipment is visible on his left.
  • Diesel starts with three trucks and adds four more, but the narrator says he starts with five.
  • After shunting the trucks, Diesel runs on the third line, but he should have travelled on the first line; the next scene shows the third line is blocked by the trucks.
  • After the trucks shout "Push! Push! Push!" steam is seen going into Thomas, indicating reversed footage.
  • When the Fat Controller looks down at Diesel, there appears to be a rip in his suit.
  • When Diesel gets very cross that he cannot pull the trucks, his face moves slightly when he rolls his eyes.
  • During the final scene with Thomas and Percy, both of their roofs are crooked.
  • When the narrator says "then fifteen," Diesel jumps backward from one spot to another, indicating a film cut.
  • When the trucks sing "Push us all, that's the longest!" the cattle truck has a dented roof.
  • When Henry leaves the docks, the leading two trucks are cattle trucks, even though two vans were in front of them when Diesel had shunted them all together.
  • In the first shot of Diesel at Brendam, he passes the cruise ship moored at the docks. But in the next shot, he passes it again. Also, the trucks are arranged differently in the two shots.
  • While Thomas is observing Diesel shunting his trucks, his eyes are wonky.


Gordon: Trucks are no one's friends.

Diesel: When The Fat Controller sees how good I am, he'll get rid of steam engines once and for all!


In Other Languages

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Language Title
Chinese Mandarin 世界上最强大的火车
Czech Nejsilnější mašinka na světě
Danish Verdens stærkeste lokomotiv
Dutch De sterkste locomotief van de wereld
Hungarian A Világ Legerősebb Mozdonya
Italian La Locomotiva più forte del mondo
Japanese せかいさいきょうのきかんしゃ
Korean 망신 당한 디젤
Norwegian Verdens sterkeste lokomotiv
Polish Najsilniejsza Lokomotywa na Świecie
Romanian Cea Mai Puternică Locomotivă Din Lume
Russian Самый сильный паровоз
Slovenian Najmočnejša lokomotiva na Svetu
Swedish Världens starkaste lokomotiv
Welsh Injan Gryfa'r Byd

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