What is it with me and couplers??? I have fallen in love with the Athearn F59 locomotives, for some reason. I bought an Amtrak a few weeks ago, and haven't had any problems with it. It's coupled to a Kato P42. I also recently purchased a Santa Fe and yesterday a Southern Pacific. For some reason, these two won't stay coupled. I have tried all different positions. Back to front, back to back, SF in front, SP in front, etc. At first I thought it was the tight curves (9-3/4" radius), but they come apart on straights too. Apparently they're McHenry couplers, which I don't have any experience with. I haven't had any problems with them staying coupled to cars with MT couplers. I also have two Athearn cabooses with McHenry couplers, and haven't had any problems with them. It looks like I could replace the couplers on the engines with MT couplers fairly easily, but is there anything else I can do?