Thomas the Quarry Engine

S18, E9: When Thomas and Diesel are sent to collect trucks from the Ffarquhar Quarry, they argue about who should be the back engine. But then Diesel suggests he take the trucks with Mavis and leave Thomas to look after the quarry until they get back. When they don't come back, Thomas gets fed up and decides to take another load of troublesome trucks on his own and then there is trouble!