Those are scale cars. As mentioned above, most detail is cast on. The ladders and brake wheels and a few details are add-on. They are based on real prototype cars also, so they are models of real cars, not imagineered.
As far as I can tell, they are the same cars as many in the Atlas O trainman line today. I have compared the gondolas and the bodies are the same. I have looked at photos of the other cars such as the "sliding Door boxcar" and "plug door boxcar" they appear to be the same bodies.
The changes that Atlas O made this time around was to totally revamp the frames, underbodies, couplers and trucks. The new trainman cars have diecast underbodies as far as I know, and diecast trucks that appear the same as the trucks in the master line. These are big changes.
However, for the price the old kits and built up atlas cars from the 80s are a very good deal. You can usually get them pretty cheap and then change out trucks and couplers and add weight if you like. It is fun to fiddle with them. If you mess up, you haven't really lost much.
I think the line offered then was the sliding door boxcar, plugdoor boxcar, ore car, the 52 ft steel gondola, and a wide-vision caboose.
I don't think Atlas has released the ore car in its trainman line.