Thanks for all the great replies. Here is the official update;
Simon- P&D makes great brass Blombergs but they are for horizontally mounted motors which would require extensive work to the existing Atlas configuration. I believe Atlas used the P&D F unit shells but not the original drive train layout.
Jim- I am going to email you, thanks for the advice. I am going to try the RS-1 wheels for one of my F's, we'll see what shakes out.
PRR 1950- P&D has the replacement wheel sets for Atlas F's and GP's in P48 and for the Atlas SD-35 in standard O . With NWSL going through a transition, they are not currently taking orders but hopefully the new owners will pick up where things left off.
BobbyD- I have been trying to get an answer out of Atlas but am having some difficulty doing so. I usually try to go straight to the horse before I put it out on the forum but you know how some of these companies can be. 
So nice to have all these replies, this forum has been a HUGE help in all my O scale endeavors! Keep up the great work.
Mike
