Diesels do not get measles, but some diesels like Mavis suffer from stripes. Then, there is friendly Rusty who works very hard and likes to keep clean, but working in a woodmill, he soon ends up looking like a ghost.
Daisy is another very proud engine who loves her name, her looks and her smart shade of green. BoCo is another really useful diesel who does not like pulling passengers, but loves to pull goods trains. Although he is well liked, BoCo does have a tendency to get in the other engines' way.
The best known diesel locomotive is simply called Diesel and he is often described as evil. Diesel often tells little fibs to amuse himself, but they often backfire on him.
- Diesel (does not speak)
- Daisy (does not speak)
- Mavis (does not speak)
- Rusty (does not speak)
- Thomas (cameo)
- Percy (cameo)
- Sir Topham Hatt (cameo)
- Diesel's bufferbeam is coloured black.
- It is said that BoCo doesn't like pulling passengers, although he has pulled them previously without complaint.