Caroline is a vintage car owned by a cricketer from the Elsbridge cricket club.
When Stepney was visiting Thomas' Branch Line, some cricket players lost their ball in Stepney's hay truck and roused Caroline to wake her up and chase the Bluebell Engine in order to receive their lost ball. However, she broke down when she finally reached Stepney and could not continue. Ultimately, Stepney's driver and fireman forgave the cricket players and Caroline, and brought the old car back home on a flatbed. Since then, Caroline is always happy when Stepney comes to visit Sodor!
Later on, the Fat Controller used Caroline to get to his wife's birthday party when his car broke down. Unfortunately, Caroline overheated and the Fat Controller had to ride in George, but he fell into a ditch. So then he had to ride on Thomas.
Caroline enjoys taking leisurely drives along the beautiful Sudrian countryside. She dislikes being pushed along too fast, as it will overheat her engine. She is very calm in nature and appreciates the engines. She loves the occasional picnic where she is parked for the duration. She used to think railway engines were silly, until she discovered how they can save the wear on her wheels.
Caroline is painted red and gold with her name written on her sides in white.