|Mavis the Quarry Diesel|
|Color: Black with yellow stripes|
|Occupation: Quarry diesel|
|First Appearance: Tramway Engines|
|Performer: Emma Watson|
Mavis is a diesel quarry shunter.
Mavis is a feisty diesel engine usually found working at the Quarry. Thomas often turns to her when the steamies and diesels need to work together.