- “Help! I'm not a truck!”
- ―Percy on the coal tipper (UK narration only)
Middle Engine is the fourteenth episode of the sixth season.
One day when Percy was collecting coal trucks from the smelter yard to take to the coaling plant, but two diesels named' Arry and Bert play a trick on Percy by shunting trucks in front of him making him a middle engine. Percy had to go slow with trucks in front and behind him and James teased him as a slowcoach. Percy had to put his trucks in front of him to the tipper for the coal to be dumped.
Percy know it is against the rules for engine to go on the tipper's loading ramp, but when his driver and firemen left, Henry arrived to collected some coal trucks, but was unaware that Percy was there and Percy was lifted onto the loading ramp with his coal dumped out and was brought back down. The yard manager was cross at Percy for causing confusion and delay and reported the accident to Sir Topham Hatt.
That night at the sheds, Sir Topham Hatt was cross with Percy for going onto the loading ramp and sent him to work in the yard until the incident is sorted out. James, hoping no one could hear him brags that he can handle 'Arry and Bert, but Sir Topham Hatt heard him and nominates James to the smelters yard to do Percy's work tomorrow.
The next morning James met 'Arry and Bert at the smelters and tells them to shunt his trucks for him. When James happily collected his trucks, he was sure got 'Arry and Bert to behave, but 'Arry and Bert play the same trick on James making him a middle engine like Percy. James said he is not a middle engine like Percy and he refuses to move, so Percy has to pull James to the Docks. Percy then jokes that James is learning to be a middle engine, leaving James angry and embrassed.
- 'Arry and Bert
- Sir Topham Hatt
- The Coaling Plant Manager
- Thomas (does not speak)
- Henry (does not speak)
- Gordon (does not speak)
- Duck (cameo)
- Annie and Clarabel (cameo)
- Big Mickey (cameo)
- Farmer Trotter (cameo)
- The Coaling Plant manager has a Bronx accent in the American narration.
- Scrap models of Thomas, Gordon, James, Toad, and Donald or Douglas are seen.
- This episode marks two firsts, one each for 'Arry and Bert:
- The first time 'Arry is referred to by name.
- Bert's first speaking role.
- This is the second episode where a character says, "confusion and delay" after Oliver's Find, but the fourth episode where the phrase is used overall. In the other two episodes, Cranky Bugs and The World's Strongest Engine, it was said by the narrator.
- This is also the first time where it is said as, "You have caused confusion and delay."
- In the US narration, the same singular recording of the line "coal cars" from Duncan Gets Spooked is used throughout the episode. This is most noticeable when Percy is approaching the tipper.
- In the first close-ups of Arry and Bert in widescreen, James is meaninglessly standing between them: stock footage from later into the episode is used. James cannot be seen next to Bert on 4:3 centre cut prints of this scene.
- In the shot after Henry arrives, Percy is pushed onto the ramp. In the next shot, he is pushed onto the ramp again.
- When Percy gets pushed onto the ramp he is not tethered to it, but he is in the next scene.
- Percy's siderods immediately change position when he is on the loading ramp.
- When Arry and Bert roll alongside James, James and Bert's eyes are wonky.
- Percy's steam platform is visible when he leaves with James and the trucks.
- In a close-up of Percy being tipped over, the rails underneath him disappear.
- Percy's cab windows are blacked out when he is on the tipper.
- In some of the scenes of Percy being lifted, his wheels do not have counterweights.
- James said he would not move, but in the shots when Percy is pulling him and the trucks, steam is coming out of James' funnel, as if he was moving.
- Percy: Oh bother!
- 'Arry: Little green piggy in the middle!
- 'Arry: Little red piggy in the middle!
- Bert: Just like Percy!
- James: I am NOT like Percy. I am not a middle engine, and I'm not moving!
- Narrator: And he didn't.
- Manager: Right on time! But what is that big red engine doing in the middle?
- Percy: Learning.
- Manager: Learning what?
- Percy: Learning to be a middle engine!