Why was Thomas' carriage taken away in Thomas and His Friends?

When Thomas arrived in the yard, he met Caitlin. Caitlin is a very fast train. Because of this, Caitlin's screws need to be repaired in the garage. Thomas left Anne and Crabbe in the yard.

Caitlin went back to the yard. Charlie told Caitlin a joke at work. Charlie told a joke about bees happily, which made Caitlin laugh. Charlie was very happy, too. Because Charlie spoke too seriously, he didn't pay attention to hanging Annie and Crabbe behind Caitlin's car. Annie and Crabbe are sleeping, thinking that Thomas has come back. As a result, Anne found that Thomas had just returned to the yard.

I didn't realize that Caitlin also offered to compete with another train, so I took Anne and Crabbe and started running, which made Anne and Crabbe feel very painful. Thomas, who chased Caitlin all the way, was panting, but the speed was too poor to keep up. Fortunately, Caitlin was finally stopped and Thomas finally got his carriage back.