Here is a Scale Model Railways boxcar from the AAR-10-A mold, which interestingly has a refrigerator car side with a box car side along with an "A" and "B " car end.
Another photo shows the roof and underframe mold. This car was built from five aluminum casting I was given several years ago to see what I could do with them. The roof was one of them, but I did not get an underframe casting, so I made one along with a wood floor for this box car. The roof, sides and car ends were epoxied together, and not fitted over a wooden block. Modern adhesives make building these old cast aluminum models a lot easier than it was in the1930's!
Yes, I know I posted these photos before. However, this thread specifically mentions Scale Model Railways.
In addition, I've included a cast aluminum two bay USRA hopper which is also built with aluminum castings like those in the first photo of the Scale Model Railways molds. This 80+ YO model has a commercially made coal load for the Intermountain two bay hopper, and it fits perfectly.
S. Islander