There was a GN Historical Society Reference sheet published on
this topic in 1989. It was entitled "The Andrew Kolb coal shed". Hope this helps. The sheet has a scale drawing of the shed, which is
fairly typical of their appearance.
Robert I'm modeling several feed mills and elevators on my 1954 Mopac layout and have been looking for a drawing of a coal shed so I could scratch- build a couple sheds to go with the grain operations - could I trouble you for a scan of the drawing?