Has anyone else run into this problem... I have quite a few Concor passenger cars with their "fixed" knuckle coupler that never seems to maintain the correct height to couple with an engine. They also seem too low to couple with Bachmann and Kato passenger cars as well. Short of replacing all the couplers/trucks with Microtrain products (which might prove to be the best and least aggravating option) has anyone discovered the "fix" to this problem? I can see no way where adding a shim would help this problem as it seems the entire car/truck assembly is too low and needs raised. Any ideas - because my Amtrak schedule is shot due to frequent decouplings and the LPPs are getting pretty upset.