Michael,

If you enhance the Rail Revolve to work like a sweep, please keep the old option as default.

Both the scale factorization and the center axis attributes of the Rail Revolve have a particular behavior that comes in handy.

And the scaling works in a radial direction from the pivot, which yields predictable results.

The scaling could be applied to the "non-linear" Z direction. This might produce a different result then sweeping. ..worth a try.