Rosie is a lavender tank engine who idolises Thomas.
Rosie is a tomboy tank engine - feisty, fun and very free spirited! She idolizes Thomas and wants to copy his every move. While this sometimes drives Thomas crazy, he has come to realize they can Really Useful Engines together. 
Rosie and the other 382 engines of her class were made in Iowa and Pennsylvania in 1942 and shipped to Britain in 1942. After the D-Day landings the engines were sent to mainland Europe to assist with the war effort. in 2006, Rosie made her way to Sodor.
Rosie was brought to Sodor in 2006 to help Thomas to shunt trucks at the shunting yard but she and Thomas couldn't get along really well until then Rosie was told to stay with Edward in his shed until she and Thomas could learn to get along with each other. Rosie later tried to convince Thomas to have fun in the rain but Thomas told her that he didn't want to get muddy and that he didn't like getting wet Rosie felt terrible but when the Troublesome Trucks pushed her into a landside, Thomas and Rocky came to her rescue. Then Rosie took part in the Sodor Championship but she had an accident whilst speeding down a hill and she was derailed but couldn't get back on the rails no matter how hard she tried. Later, Rosie tried to show Thomas how well she can comunicate with nature but Thomas didn't believe her and left. Rosie is sometimes unbelievable.
Rosie is a friendly and respectful tank engine. She and Thomas like to have fun and also like to help each other when they are doing work.
Basis EditRosie is based on a SR USA Class 0-6-0T. Ironically, fifteen of these engines were sold to the Southern Railway where they were used as dockyard shunters, replacing the ex-LB&SCR E2s, Thomas' brothers.
- Teresa Gallagher (UK; thirteenth season onwards)
- Jules de Jongh (US; thirteenth season onwards)
- Rosie's model is currently on display at Drayton Manor.
- Rosie has both her whistle and connecting rods in different positions compared to her prototype:
- Rosie's whistle is positioned behind her rear dome whilst her prototype has its whistles positioned on the right side of the middle dome.
- Rosie's connecting rods are attached to her middle driving wheels whereas her prototype has its connecting rods attached to the rear driving wheels.
- In Red for Rosie, one image has her with a tender.
- Rosie's whistle sound is really Thomas' in a higher pitch.