i hate this "how are skis on rails" question.
there really is no such thing as a bad rail ski.
there are softer skis and stiffer skis, but that is all preference.
sure a pair of hellbents might not be ideal for lip 4 pretzel 4 ing a rail, but to someone else they may be exactly what they are looking for on rails, good for presses, whatever.
moral of the story, chronics will be fine on rails, just like any other park or all mountain ski.