Episode XVIII: The Devious Diesel was uploaded on May 19, 2016 and is the 2nd episode of the third season. It is the first of a two part story.
The story will be a flashback of when Diesel first arrived on Sodor, only showing how the Fat Controller found out about his lies and sent him away. Basically, it will be what happened while Duck was at Wellsworth.
- Sir Topham Hatt
- Duck (does not speak)
- Percy (cameo)
- Thomas (cameo)
The following appear in present day
- Donald & Douglas
- D199/Ted (cameo)
- Thomas1Edward2Henry3 was always disappointed that it never showed how Diesel got his comeuppance. He was originally going to use it for a NWR Origins episode about Diesel, but scrapped it as Diesel is not part of the NWR 11.
- Events from Duck and the Diesel Engine are shown.
- Originally, this was going to be one episode, but the script proved too long to be squeezed into 15 minutes.
- As of November 3, 2016, this is by far the shortest episode of The Engines of Sodor, with a length of 7:52. However, this is partially due to the shorter intro then previous seasons and the fact that it was originally supposed to be one episode. But even with the longer intros, this still would be under 9 minutes, still making it the shortest.
- This episode features a custom arrangement of Diesel's theme by Thomas1Edward2Henry3.
- Because of the limited faces of Diesel's 2012 model, the 2006 model had to be used for some shots.
- Ironically, both this and Double Muddle open with the rain sound effect.