RailClone uses surface by projecting the geometry along the RC object's local Z axis, so you will get better results if you align the object so that as much of the surface as possible is perpendicular to this axis. In the attached file I've rotated the object as you can see here:
I've also turned on the Segment's Align Y with Surface
option so that it deforms to follow the curvature of the surface on the X and Y axes.
I hope that helps, please let me know if you have any further questions.