For my On30 roundhouse I'm trying to add details that would have been common in the 1920's.  I've been able to visit roundhouses in Baltimore (Ma & Pa) and Savannah (Central of Georgia Railway) but most of my inspiration has come from internet searches.  The Savannah roundhouse had wood block floors and rectangular smoke jacks that I copied.  The Baltimore roundhouse had wooden truss framing that I used in my modified Thomas Yorke model.  I added inspection pits based on Central Pacific RR drawings.  I also added a drop pit with a hydraulic lift

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