The Fat Controller
Thomas has an accident by trashing the Stationmaster's breakfast and has to be sent to the Works. The Fat Controller orders a diesel railcar named Daisy to help out in his absence. Daisy is rather vain, neurotic, and convinced she knows it all, and decides that she is only going to do the work she wants. After a stern talking to and an accident by Percy, she is allowed to stay, a wiser engine. At the end of the book, Thomas comes back.