|This article is about the Story Library book. You may be looking for the character, the Buzz Book or the episode.|
- “I'll show that fusspot Toby!”
Mavis, re-titled Mavis the Diesel Engine in 2012, is the tenth book in the My Thomas Story Library series.
Mavis has high-spirits which one day puts Toby in terrible danger. She soon rushes to his rescue and the pair become good friends.
- This book is based on the stories, "Mavis" and "Toby's Tightrope" from the Railway Series book, Tramway Engines.