Excellant point on availability - over analysis is a risk - but theDave
Sunshine and Speedwitch now offer 50' resin kits, so that
helps. And most 50' cars in your era were composite wood,
and there are even more kits for that. The SP fleet of 50'
steel cars in WWII was about 2,500 cars, a large fleet for
that era -- 80% were double door automobile cars.