'Arry and Bert play a trick on Percy by shunting trucks in front and behind him, which leads to Percy being pushed onto the coal tipper by Henry by mistake. Percy is sent to work in the yard until the incident is sorted out, and the Fat Controller nominates James to do Percy's work after he makes a snide comment. When 'Arry and Bert play the same trick on James, he refuses to move and so Percy has to pull James to the Docks. Percy then jokes that James is learning to be a middle engine, and James gets heavily embarrassed.
Tropes featured in the episode:
- Bully Hunter: While he didn't bother to defend Percy since he teased him earlier, James declares that he won't let 'Arry and Bert make him a middle engine. He was wrong.
- Characterization Marches On: When 'Arry and Bert first appeared in "Stepney Gets Lost", they were seen as villainous in attempting to scrap Stepney even with an unsettling voice saying "Bye bye, Stepney". In this episode, they are nothing more than mere bullies always harassing steam engines.
- Jerkasses: 'Arry and Bert. Even James didn't help Percy's cause.
- Karma Houdini: 'Arry and Bert are not punished for their misdeeds.
- Kick the Son of a Bitch: 'Arry and Bert does this by putting trucks in between James.
- Laser-Guided Karma: James who teased Percy for being a middle engine gets one as the diesels made him one as well. Now it was Percy's turn to laugh at him.
- Never My Fault: The Fat Controller blames Percy for going on the tipper although it was Henry, who had pushed Percy to it with his coal cars. Though in Henry's defense, he didn't know Percy was there, because he was collecting coal cars and the coal cars bumped into Percy, causing the little green engine to be hoisted on the hopper.
- The Worf Effect: Duck makes a cameo showing the concept of middle engine. Though how he ended up that way isn't shown, it's likely he fell for 'Arry and Bert's tricks too.