Sirenwerks: Yes, I knew they were the same cars, but wondered what the GN used them for before renumbering them. Apparently general purpose boxcars?
To make things even stranger, the GN reused the 21950-21964 series in 1961, although stopping at 21961, for a small group of wood-sided steel frame cars. These cars had roof hatches added, to transport foundry sand, even though covered hoppers were in common use by then. 21953 (2nd) seems to have been the only GN car ever painted Vermillion Red with the BSB-style lettering.
So there was at most two years, and possibly only a few months, between the PS-1s being renumbered and the series being reused.
