USA Trains 4 bay hopper rail clearance?

[gmpullman]

Hi, Folks
I just put my three new USA Trains four bay Center-Flow hopper cars on the layout for the first time. While pushing the cars by hand to check out their tracking characteristics I heard a scraping sound.
Upon further investigation I found that the hopper door operating mechanism was actually scraping the rail head. This was at a point where there was a very slight crest of a small rise in the track.

I wonder if anyone out there has found a cure for this aside from cutting off all that nifty hardware for the door mechanism?
I'm guessing the simplest solution would be to shim the truck bolsters and then sajust the coupler height accordingly.

Anyone know of another cure?

Thanks, ED