mooniteman wrote:
This is friggen fascinating. And you would think that the ride would require little heat and more cooling for the mechanics. Can't imagine they would have a furnace blasting so hot that it would burn it like that from the inside. Seems rather unlikely. Although I did have a bed that went near black in parts from sitting against a furnace - so who knows.
There's nothing mysterious about it.  It has nothing to do with heat or burning.  Furnace heaters are simply dirty.  That's why they have filters.  You get soot stains on nearby walls and ceiling sooner or later.  And of course there is a heating as well as cooling system in there.  It's like a large warehouse.