Watch Out Wilson / Wilson’s Smooth Moves

S1, E216: The trainees are trying their wheels at pulling rolling stock around an obstacle course. Ambitious Wilson tries the fire wagon. The course seems easy - until Dunbar tells them they have to do it backwards! / The chuggers are learning to carry passengers comfortably, using dummies specially made to wobble if the ride isn't silky smooth. Wilson struggles and Eddie has an idea of how to help him. Will he be able to become a smooth mover in time for the test?