“That's me, the world's strongest engine!”
“Is that all you can haul? Henry's loads are longer. Is that all you can haul? Henry must be stronger.”
―Troublesome Trucks

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


When Henry has had an accident pulling a goods train and is sent to the works to be mended, Devious Diesel unfortunately is the only spare engine available. The engines are not very happy about this, seeing that they know Diesel is troublesome.

The next day, as Diesel is working at the docks, he brags to the trucks that when the Fat Controller sees how good he is at shunting trucks, he will get rid of steam engines once and for all. The trucks tease Diesel as he is shunting them, saying how Henry can shunt more trucks than he is, so he boasts he can push them all at the same time.

Diesel then arranges a line of twenty trucks, but soon finds he is unable to move them (unbeknownst to him, a shunter has put the brakes on), so Diesel decides to pull them instead. He pulls so hard that he breaks loose and falls off the quay and onto a barge. Henry, who is now repaired, arrives at the docks with the Fat Controller. He is cross with Diesel and sends him home in disgrace.

Henry then backs up and pulls away from the docks, pulling the line of trucks easily and the engines all agree that even trucks can be helpful sometimes, like helping to get rid of Diesel.


  • Thomas
  • Henry
  • Gordon
  • Percy
  • Diesel
  • Sir Topham Hatt
  • James (cameo)
  • Duck (cameo)
  • Oliver (cameo)
  • Annie and Clarabel (cameo)
  • Big Mickey (cameo)
  • Farmer Trotter (cameo)
  • The Storyteller (cameo)
  • Salty (deleted scene)


  • Tidmouth Sheds
  • Brendam Docks
  • Calla


  • S.S. Vienna from TUGS can be seen.
  • This episode may have been inspired by the magazine story, Showing Off.
  • Some shots of Diesel attempting to move the trucks are sped up.
  • This episode marks several things for Diesel:
    • His first speaking role since the third season episode, Tender Engines.
    • His only appearance in the sixth season.
    • His first appearance since the fourth season episode, Rusty to the Rescue and although he did not appear in the fifth season since his music video cameo.
    • His first time trying to pull a line of cars with the brakes on since Pop Goes the Diesel
    • The last time he was sent away from Sodor. Stories afterwards state he is a permanent resident of Sodor.
    • The last episode to feature him as the main character until the fourteenth season episode, Diesel's Special Delivery.
  • In both the UK and US versions, Diesel shouting "HELP!" as he falls off the quay is later used for Duncan in the episode later on in this season, Dunkin Duncan.
  • Salty was intended to have a role in the episode as he appears in a deleted scene.
  • In the first scene, Clarabel is facing the wrong way.
  • 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, filming equipment can be seen to 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, he 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 "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.


  • Books - Diesel and the Troublesome Trucks
  • Magazine Stories - More Mischief! and Sodor's Strongest Engine
<< Season 5 Season 6 Season 7 >>
#01 Salty's Secret #10 Twin Trouble #19 Buffer Bother
#02 Harvey to the Rescue #11 The World's Strongest Engine #20 Toby Had a Little Lamb
#03 No Sleep for Cranky #12 Scaredy Engines #21 Thomas, Percy and the Squeak
#04 A Bad Day for Harold the Helicopter #13 Percy and the Haunted Mine #22 Thomas the Jet Engine
#05 Elizabeth the Vintage Lorry #14 Middle Engine #23 Edward the Very Useful Engine
#06 The Fogman #15 James and the Red Balloon #24 Dunkin Duncan
#07 Jack Jumps In #16 Jack Frost #25 Rusty Saves the Day
#08 A Friend in Need #17 Gordon Takes a Tumble #26 Faulty Whistles
#09 It's Only Snow #18 Percy's Chocolate Crunch
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