I wanted one so badly, I made this one. It was in the "BC" era (before computers were common and information was more difficult to find). All I had were a few photos of UP cars taken at angles.
A Walthers roof, roof vents and six baggage car doors were bought, along with a pair of All Nation 6 wheel trucks, passenger car brake and generator detail. Both ends are built up in wood, with the standard end covered with a sheet of thin soda pop can aluminum with rivets embossed with a pounce wheel and straight edge. The opening end had hinges which were cut down to suit.
The car sides are made from aluminum roofer's flashing, sold in rolls at hardware stores. I made a paper pattern which was glued on with rubber cement to guide cutting out the door openings and making rivet lines. Scale Coat paint was used along with a set of Champ decals. Central Locomotive Works couplers are on it. Kadee O scale couplers had not yet been made. All told, not too bad a job.
BUT the model is a scale 10' too short! I could not find the length of the UP baggage car I modeled and made a 'guestimate' about that based on the photos. So here it is, built in 1975.
S. Islander