Mavis is a female tramway quarry Diesel. She works at Ffarquhar Quarry and likes to rearrange trucks into different sidings.
When Mavis first arrived on Sodor, she does not take kindly to Toby's advice and ended up got stuck on a Level Crossing due to icy rails and Toby had to help her. But Mavis redeemed herself after saving Toby from a collapsing bridge and continues to work at Ffarquhar Quarry. Although Mavis likes working at the quarry, she also loves to see the rest of the Island of Sodor, so whenever a large train of stone trucks is too much for one engine, Mavis always offer to help and gets to see the rest of the Island, especially the seaside.
- HO Scale
- She was the first Diesel engine that Bachmann produced for their Thomas & Friends range.
- An early prototype image depicts her model's paintwork as being light grey.