I had been reluctant to purchase Atlas locomotives due to the fact my layout contains some of the old 24" radius curves. My Weaver locomotives negotiate these curves with no problem other than a slight filing of the shank on the 805 couplers.
I received an Atlas U-23B from the bay and placed it on my tracks. It went around the curves with no problem. Temporarily I have placed one of my old AHM "C" liners behind it with truck mounted couples to pull the train. All is well!