Air date: October 22nd, 1986
Adapted from: More About Thomas the Tank Engine, "The Runaway"
One day, Thomas wakes up feeling ill. Workmen are unable to make him feel better, so the Fat Controller is forced to send Thomas to the works for a while. He then asks Duck to take over Thomas' duties on the branch line. Duck is delighted to be given such a responsibility.
Duck is already friends with Percy, and quickly befriends Toby, Bertie, and Terence, who tells Duck to take extra special care with Annie and Clarabel. Duck is very gentle with them, and both coaches are left very impressed with the Great Western engine and remark on what a pleasure it is to go out with him. When Thomas returns from the works, the two coaches tell him how well Duck had managed on the line. Thomas doesn't feel jealous, as he's just happy to be back home.
Although he's back from the works, Thomas isn't in complete working order. His handbrake has been left very stiff, meaning it can feel like his brakes are hard-on when they're not. Because of this, Thomas begins to overrun the station platform, embarrassing him greatly. Eventually, Thomas' crew learns to compensate for the handbrake, and they stop in just the right place.
Thomas' fireman falls ill one day, and a relief man takes his place. Thomas arrives at the station and the new fireman couples him to Annie and Clarabel, then joins the driver and stationmaster on the platform while they wait for Henry to deliver his passengers. However, the relief fireman has forgotten about the stiff handbrake. Soon, Henry starts to approach with his train. But as Thomas' brakes aren't completely on, his wheels start to move, and Thomas can't stop or whistle a warning without his crew. Before anyone realizes what has happened, Thomas has left everyone stranded on the platform.
Annie and Clarabel scream for Thomas to stop, but he has plenty of steam and keeps going. Soon, an alarm goes out about the runaway train. An engine inspector makes a plan, boards Harold the helicopter, and flies to a station where Thomas is due to pass.
When Thomas reaches the station, he's very tired and is moving far slower than normal. The inspector then makes it to the platform And when Thomas passes, the inspector scrambles aboard the cab and puts Thomas' brakes on, finally bringing the tank engine to a stop. Both Thomas and the inspector are very relieved and thank Harold, who tells them it was no problem.
The inspector tells Thomas that they must make sure this never happens again. Thomas, exhausted, agrees with him.
Tropes featured in the episode:
- Big Damn Hero: Harold.
- Compressed Adaptation: Also counts as Disneyfication. References to Thomas and Percy still on bad terms from the book version of "Thomas, Percy and the Coal/Double Trouble" are omitted, since the show resolved their feud in the same episode.
- Dissonant Serenity: Averted for once. Duck and Edward have visibly concerned looks towards Thomas' ill bout. Arguably played straight with Henry, as he still has his smiling face, when Thomas begins to run away, looking visibly distressed (although it is possibly a blooper).
- Downer Beginning: The scene where Thomas felling ill and is miserably taken to the works.
- Green-Eyed Monster: Subverted. When Thomas came back, Annie and Clarabel told him how well Duck had managed while he was at the works. Upon hearing this, he was so happy to be home that he forgot to be jealous.
- Halfway Plot Switch: The first half of the episode deals with Duck taking over Thomas' branchline while he's away and how Annie and Clarabel become as fond of him as they are with Thomas. Once Thomas returns, the plot switches to him dealing with his faulty handbrake and how it leads to the titular runaway.
- Jerk with a Heart of Gold: This was the first time Harold showcased his helpful side towards the engines, despite how he looks down on them and right after his debut episode.
- Oh, Crap!: Thomas after he begins to move and can't stop without his crew.
- Runaway Train: Thomas due to his faulty handbrake.
- Stock Footage: Stock footage from "Thomas and Bertie", "Old Iron" and "Percy and Harold" is used. A deleted scene from "Thomas, Percy and the Coal", an alternate shot from "Old Iron" and a mirrored one from "Percy and Harold" are used too.
- Think Nothing of It: Harold says this to Thomas in the end after he thanked him for bringing the inspector to put his brakes on.
- Title Drop:"Stop the runaway!"
