Hi,
Unfortunately RailClone will only import the object directly referenced by the RailClone object, but not its dependencies. The only option, as you point out, is to collapse the stack or add the preset to the existing scene using Application Menu > Import > Merge instead. Although for the latter you lose the benefits of using the library browser.
However we're grateful for the useful feedback, and we'll look at how we can implement this feature in a future release.
Many thanks,
Paul