Thomas & The Trucks

"I'm tired of pushing coaches. I want to see the world!"
Thomas was bored with his job of shunting coaches and complains to the other engines about it. One night, Edward offered to swap jobs with Thomas: he would shunt the coaches while Thomas took his trucks. Thomas happily agreed.
Unfortunately, Thomas did not know how troublesome the trucks could be and lost control of them. The trucks pushed him down a hill and Thomas was barely able to stop before some buffers, preventing a nasty accident. The Fat Controller appeared and advised Thomas that he should learn more about trucks if he is to become a Really Useful Engine.