S1·E22 Thomas in Trouble

There is a Quarry at the end of Thomas's Branch Line, and he has to take the trucks to and from it. One day a new Policeman starts work and tells Thomas off because he has no cowcatchers and sideplates. It turns out this is the Law, so the Fat Controller will have to build them for Thomas. Thomas says he will look like a tram. But rather than give Thomas a tram overhaul, a much better idea has come into the Fat Controller's mind...