Mark,

After attending Frank Hodina's clinic on making resin masters for
single sheathed box cars, I am much more willing to try to create
something new than I was before. And you don't have to make masters.
You can just make two identical sides from styrene. The trick is
to have the correct dimensions and draw right on the styrene base.
Rivets come last (Frank uses tried and true Athearn donor rivets)
and trimming and sanding the parts is the final step.

So all you have to do is figure out how to kitbash those 3/3/3 ends
and you're almost done!

Frank fabricates hat sections with .005 styrene base (.060 wide?) with
a styrene strip (.040x.060?) for the raised part. (You can figure out
the correct sizes to use if you have a drawing.) He says a standard
horizontal board width was 3 1/4" (or something like that) that you
can use standard Evergreen strips for. DON'T USE scribed siding --
use individual boards up tight against each other or use a sheet of
styrene and scribe the board lines. Frank used to use the scribed
sheets but he finally seems to have mended his ways!

Just doing a side should not take you more than a couple of evenings.
Once you do one side, the next one should take half as long.

P.S. Frank uses Testor's liquid cement -- he says it works much more
slowly than Tenax. He uses it generously on the hat-sections and the
styrene actually melts slightly, rounding itself off and filling in
the corners to create a convincing hat section! Obviously you should
experiment with this before trying it on the car side.