A retired agent-operator tells me that the structure covering the platform at the Keokuk Union Depot (photo below) was called the "train shed." We preservation project volunteers sometimes call it the "canopy," but my understanding is that a better term for this type of structure is "platform umbrella." In my reading over the years I have seen the term "train shed" used to describe a large structure spanning several tracks at a major terminal, usually with skylights and vents to let smoke out. I am thinking maybe there was such a train shed at Chicago's Union Station, and that the term was adopted to designate the platform structures at smaller CB&Q depots even though they did not actually cover trains. Can anybody supply the standard terminology for this structure? Thanks!