Thanks for contacting us. The main issue here is that the clipping spine and the surface are coincident. Internally RailClone, creates an array that is larger than the clipping spline and then performs a boolean operation to remove the excess. Because of this the surface needs to be larger than the clipping spline to ensure the edges don't deform in unwanted ways. You can then rotate the entire array using the generator's Clipping Area > Z Rotation property.
Please see the attached file for an example. I hope that helps, please let me know if you have further questions