An etching kit maker called World Craft in Japan has put on sale the Chichibu Railway Teki 100 boxcar (HO scale). The appearance of fine vertical grooves on the sides is exactly "Transco Side." ATSF's Bx-86 and CB&Q's XM-4 are associated. On the Internet, I found a model of the latter with 3D printer. Do you know other prototypes? Have you built the model?
Kuriu, KotaroKyoto, Japan
I cannot get the picture to show detail clearly, but if these are Transco Tri-Rib sides you may find the PDF of the Transco parts catalog valuable in deciding what some of the details should be.