This seldom modelled but very common structure was found in any number of locations on the railroad. It housed a small amount of coal used for the caboose stoves and a section containing coal oil (kerosene) for the lamps used by the train crew and for switch signals. They were always found where cabooses were stored and often near stations, and way buildings where small amounts of coal for the stoves and a spare supply of coal oil was needed.  Surprisingly these little buildings were in used well into the age of the diesel. The footprint is 3" x 1.75"