Request for script help.

Here is my latest effort to script a chain.
It is unsuccessful so far.
The sweep goes into endless calculation, trying to sweep a scripted circle over the scripted rounded rectangle.
Based upon the Pipe2 script, it should work, but it uses a scripted rail, not an interactively selected rail.
Is it a problem with the rail? Is the rail a list or an object, with one or multiple parts?

Studied quite a bit Michael's and Martin's posts, asynchronous sweep, .calculate() versus .getCreatedObjects(),
and did a lot of permutations, but the sweep does not work. (Many tries ago I did have a sweep formed when changing the profile radius, but
that version is long gone...)

- Brian

Edit, deleted obsolete chain maker script draft