When Carly first arrived to Brendam Docks, Cranky feared that he was going to be replaced. However, he later warmed up to her. She was so keen that she took on all the work, which made Cranky jealous and he frantically tried to outdo her. However, their hooks became entangled and they found themselves stuck fast and unable to move. As they both tried to pull away from each other, Salty told them that they needed to work together. After they were able to do so, Cranky apologised for being jealous, while Carly also apologised for appearing to be desperately trying to hog all of Cranky's work.
Later on, Thomas managed to talk her into loading him on a ship heading away from Sodor, but it caused worry for the others when they found out.
Carly is a bubbly crane who is happy to help out. She is friendly and is able to make friends with almost anyone. While she can be a bit over-enthusiastic about her work, she only wants to be really useful.
Carly is based on a Chinese portal crane built by Xinxiang Kehao Machinery Equipment Co., Ltd, which is extensively used to load and unload at ports and material handling at shipyards and metallurgy industry. Cassia is also a member of this class.
Carly's main body is painted bright yellow and has dark blue railings and stairs. Her name is written in dark blue on each side of her cab and she has a dark blue section above her face and has black hazard stripes on her superstructure and base.
- Series 21 - Cranky at the End of the Line, New Crane on the Dock and A Shed for Edward (cameo)
- Series 22 - Forever and Ever (cameo), Seeing is Believing, Apology Impossible (cameo), Thomas' Animal Ark, Rosie is Red (cameo), Counting on Nia (does not speak) and Hunt the Truck (cameo)
- Series 23 - Chucklesome Trucks (cameo)
- 2018 - Big World! Big Adventures!
- Lucy Montgomery (UK/US)
- Misa Ishii (Japan)
- Dolores Mondragón (Latin America)
- Birgit von Rönn (Germany; Seeing is Believing only)
- Ines Nierstenhöfer (Germany; Thomas' Animal Ark only)
- According to Lee Pressman, Carly was originally meant to be called Mildred. However, the name was changed as the producers felt it sounded too old. Salty called the Sea Serpents Mildred in his story as a reference to the original name.
- Carly is the first character to be based on a machine built in the 21st Century.