Mike,
I have the same problem as we use loads of LGB R5 switches, but you can easily just bend the USAT pickup skates slightly so that they don't get stuck, or even better is to replace them with massoth shoes as they are just that little bit fatter that they don't seem to fall in. I normally just replace the shoes on most of my USAT geeps as I know then that I won't have that problem.
All the best,
Gavin