The firemen help maintain the engines, along with the Drivers, keep the engines in control and provide a voice of reason when the engine is being difficult.
While the train is moving they stoke the fire and keep the water level where it needs to be. After a trip, they clean the firebox. They also couple the engines if a shunter isn't around. A fireman's uniform is blue trousers, a white shirt, and a black tie, with a blue jacket over it, and a blue cap.