Welcome to the forum, Steve! A coaling station is a structure that is unique to steam engine operation. It's a huge bin that contains coal for the engines to burn. Usually, it straddles the tracks so the engine can position it's tender below a chute. Once the chute is opened, the coal pours into the tender until it's shut off, again. A coaling station will normally include a conveyor or crane of some sort to reload the bin; by extension, a pile of coal or a coal car would be at the other end of the crane or conveyor's reach.