Yeah that’s true but a lot of work to do 10 cars. Do you think this is something that can be cast? I’d be ok buying one car to make masters from if that’s plausible. I’m leery about how things the casting would be.
You coulf fabricate fairly fast with a jig and parts from Central Valley and Tichy. Might find the corner gussets from someplace else too or just have them 3-d printed. 3-d has come a long way but is not yet to the point of being cost effective for this whole project.
Having something like that 3D printed would probably cost more than the auto rack in the first place. Plus the time and effort in developing the model is going to be a considerable undertaking. I’d just ebay the flats (even at a loss) to help finance buying auto racks
I like that picture. My father used to have a 1959 Plymouth Savoy that he restored. As for an answer to the original post, I’m afraid you’ll probably have to make your own. I think Athearn used to have a kit for the 50 foot autloaders to convert a flatcar into an auto rack but I don’t think anybody’s made 89 foot racks by themselves.