Seems the coupler nuckle shape is different in all truck designs just slightly. Maybe the moldes or just the design of them. I to had trouble with a sound box car. I luckly had some new style trucks a forum member sold me. I unscrewed just the knuckle piece off each truck and swaped them. Now the car works with anycar I have. So not sure how slight the difference in the knuckles themselves, but ones worked fine and the others did not.
The reason I had to remove the knuckle only is the coupler shank piece was to long on the ones bought here off the forum as apposed to the ones on my box car. Different lengths probably for different cars such as hoopers and tankers.
I liked these couplers at first. The first cars I got with them worked great. After buying several ps1 box cars used with the old design swivel coupers with hidden tabs. I see what everyone is saying. I now have changed my mind about these new couplers. Especially having to file and grind on them right out of the box to get them to play well with all my other cars.
Maybe the old post war design with the hidden tab and tab on the side for manual uncoupling could be brought back. This design always worked. Just my 2 cents here.
