The man from Purdue beat me to the punch. Atlas couplers have to issues -- the centering springs and the knuckle springs. Both are way stiffer than they need to be. To add to the mix, some of the older couplers also had zinc rot/zinc pest. I'm examining some Kadee 700 series to see what I'd have to do to get them into an Atlas box, which is actually nicer than the Kadee box in my opinion.
Down the road, if you want to replace the Atlas couplers with Kadees, the Kadee boxes will mount on the standard Atlas mount if you use 2mmx8mm metric screws in the holes, but you'll have to shim the boxes down a bit as they'll be abut 1/16" too high.
