A ruse I’d like to have tried in replicating these wagons would have been to imitate the dents etc. that accompanied the flaking paint and rust patches.
What I had in mind was to remove the odd panel or two and replace with annealed brass ‘plates’ which had been subjected to a spot of ill-treatment with the odd tool or two.
I had a bash at this several years ago during my dark-side days, but on a replacement brass fabricated fuel tank of a cheap Bachman GP38 in Ho gauge.
The dents look a little severe but the inspiration were taken from actual prototype loco sporting these deformities, which were gleaned from myriad photos of US locos I found on the web.
The tanks still needing finishing in the accompanying photos, including further detailing, and the body looks a little high on the chassis as it was just ‘plonked-on’ for the shoot.
Perhaps you might like to give it a go to see what they’d look like?
Jonte