|Actually, the Silver City car drawings were in the May/June 1992 Gazette. I have never seen any other drawings of these cars.
I wonder if the Silver City cars might have been using some common design parts? The reason I say this is that there is a photo in book, Rails of the Couer D'Alene, which shows a 3' gauge mining line with a train of ore cars that remind me of the Silver City cars. Has anyone else seen this? I don't know much about the design and origin of either railroad's cars, but the design certainly seems robust and well-thought out.