I suspect many of the USRA rebuilds spent their last days in various lease fleets. The Soo Line found itself short of boxcars after WWII and ended up leasing 1500, IIRC, cars. What they received was a motley collection of USRA steel rebuilds and decommissioned 40' auto cars; impossible to tell which roads they came from as the lease included repainting and application of Soo graphics. These only lasted 3 or 4 years and then they were gone. I assume other roads finding themselves short of boxcars did likewise.

Dennis Storzek