- "Its not fair! Why can't I be in a book like the others?"
- ―Frank, Jock the New Engine
Frank is a grumpy diesel who lives and works on the Arlesdale Railway.
Frank was constructed at Arlesburgh Works around 1967 out of bits and pieces from several other engines. He is powered by a Perkins diesel engine, and was named after its creator. He is a shunter, and is used for maintenance work and empty carriage workings across the Arlesdale Railway.
When Small Railway Engines was first published, Frank became infuriated when he found out that he had been left out due to the Thin Clergyman not being aware of his presence. He then refused to come out of the shed the next morning, but when he did, he only resulted in running into the back of the shed, cracking a shed support. He then felt ashamed of what he had done, but later redeemed himself by rescuing Rex when his steampipe leaked and needed his train. Believing Frank shouldn't have to do rescues, the Small Controller realized the railway needed another engine, which was Jock.
Frank means well and has a good heart, but can tend to be grumpy.
Frank is painted light grey with a red stripe around his body. He has red nameplates with his name in gold on his sides.
- He is named after engineer Frank Perkins, creator of the Perkins diesel engine.