Diesel Day! is a magazine story.
James is having a sneezing fit at the station. Thomas reminds James that "coughs and sneezles spread diseasels". No sooner had James sneezed than Diesel oiled into the station. Then BoCo, Mavis, Daisy, The Diesel, and Diesel 199 all arrived. Thomas was cross as he thinks that James caused all the diesels to arrive. The Fat Controller tells the engines that its "Diesel Day" at the station where people can admire the diesels. Thomas tells them that the thought of a "Diesel Day" makes him feel ill, so he calls it "Diseasel Day".
- Sir Topham Hatt
- Diesel (does not speak)
- BoCo (does not speak)
- Mavis (does not speak)
- Daisy (does not speak)
- The Diesel (does not speak)
- D199 (does not speak)
- The phrase "coughs and sneezles spread diseasels" is a reference to the second season episode, The Diseasel.
- D199's buffers and coupling are conjoined to his face.