Hi,
The clipping path uses the RailClone object's local axes to determine the X/Y area, so you must rotate the Z axis of the RC object and the spline align. However if you are using the generator's Z Rotation property to create the diagonal patterns, you may have issues with the style in a vertical alignment. To prevent this, set Z Rotation to 0,manually rotate the railclone object and then reasign the clipping spline.
I hope that helps, if you are able to upload your file I'd be happy to look at it in more detail.
Kind regards,
Paul