A summer heatwave brings record numbers to the railway, though joy turns to despair for the staff when it looks like the railway will be prevented from running its iconic steam engines through a tinder-dry national park. Through a series of expensive preventative measures - including hiring in a couple of heritage diesel trains and having a makeshift fire truck follow every engine - boss Chris manages to keep the business running. The engine shed workers are also kept busy trying to get star locomotive Eric steaming again