The floor is basically a sheet of heavy brass with the long side edges rolled to slide into the bottom of the body. Holes drilled out for screws that attached to soldered on L channels with tapped holes in corresponding areas along the inside flanks of the body. All the details are attached to this sheet of brass. When the builders put a lot of these together the heat I assume perhaps cause the brass to warp and or the way the parts sit on the sheet causing some shearing forces and resulting in the twist. Furthermore the sides, ends, and rood were all formed and built up I think separately off the floor. With no way to control the squareness, the body was compromised. It is a relatively easy fix and worth doing. If you don't do this some I mean some, not all of them will sit crooked or lean funny. I have found that a minor adjustment on the bolster is all some need. Truly these were hand built models. I wish they used a form in the process than building them on their laps watching TV!
The troubles ones are all easily fixed. I have several that were perfect right out of the box. And depending on the builder the severity of the issue was better or worse. I had a gentleman tell me they are all "junk-junk! - garbage".... I tried to explain that any competent modeler could repair the problems, well worth the effort, well there you have it, "effort". But I forget often, today many of these folks are arm chair modelers.. If they can't take it out of the box and run it its junk to them. Fortunately for O scale especially for these cars PSC did us a HUGE favor for importing these fine models, all of them.. freight, passenger, and locomotives.. All I need to do is pull them out of the box adjust here there and paint, final detail. Sure beats the Hell out of a box of sticks and some sheet styrene! Now we enter the RTR era and a lot of good stuff is made in RTR.. but what stuff? I need exactly what Atlas is refusing to produce.. "no market for a run of 15,000 so we are not going to make a injected model of that.", Enter - brass models. go figure. GGD has made us 8-1-2, 12-1 Pullman cars and select PRR head end cars in RTR injected plastic, but they are loaded with inaccuracies that I am not willing to live with, over size vestibule doors, sitting too high (3 rail origin), funky coupler mounting adventures, lack of details, etc. These PSC cars are not without errors either like the contour of the roof ends but that was an Ooops on behalf of Robert Hundman's G.O.D.'s PSC used to build these with. I personally don't see the big deal.. One look at the oversize doors on the GGD's and you learn to look past it real quick, at least I do.
The PSC heavies are spectacular, I wish they would have done more like an 8-5 or 6-6 Poplar series cars..
But I am very happy with the cars they did and I am very pleased with the results. Yes I needed to tweak and fiddle a little; it's O scale not a plastic N scale car.. Look at Louis Bartig, can you imagine what he is thinking when these ignoramus dingy guys say things like, "If I can't drop it on the track out of the box and watch it go, well then it is junk!!!"