Mavis:

Mavis is a young diesel who is full of her own Ideas. She arranged the trucks to make Toby cross. After helping Toby off a broken bridge, she was allowed  to come down the line. She works at the Quarry at Ffarquhar.

Debuts S3: Mavis

The Diesel:

The Diesel is a snooty chap who thinks that steam engines should be scrapped and diesels should take over. But his plans turned out for the worst as he conked out while rolling up to his coaches. Later he left two things behind as he left Sodor: a rather nasty smell, and a battered bowler hat!

Debuts S4 - Bowled out!

Iron Arry and Bert:

‘Arry and Bert are two of the meanest Diesels on the Island. They are great friends with Diesel and love to make steam engines “piggies in the middle”.

Debuts S5 - Stepney gets lost.

Salty:

Salty is a weather beaten dockyard diesel who works at Brendam Docks. He was first sent to work at the Quarry, but was unhappy to find that he would not be working by the sea. But after working there, The Fat Controller sent him to work at Brendam Docks.

Debuts S6 - Salty’s Secret.

Dennis:

Dennis is the newest Diesel to arrive on the Island of Sodor. I am sorry to say that his is the laziest diesel to come to the Island. He tries to avoid any work but gets found out. He was found out for his laziness and was soon sorry.

Debuts S9: Thomas’ Day off