Brep to Surface and strange lines

First is the process for the code attached:

I made 2 circles, a catenary between 2 points (one on each circle), and then I "rotate 3D" the catenary around the circle, and found the points on those curves that "intersect" a plane placed on Z=6 above the first circle. I did this to have a collection of points from which to choose 3 and make a 3pt-circle.

[this second circle "fits" the catenary at a certain height, that's what I wanted to do]

Maybe it's obtuse but anyway that's the way I managed it.. I then used the "intersection" of the top circle with the original catenary curve to "split" the catenary into 2 parts, I then "Rail Revolution" the first part of it around the axis of the original circle, using the circle as a "rail", and I get a Brep surface.

It is a "open brep" surface, so now i'm having the problem of managing it if I want to subdivide it with Isotrim or other commands to control the number of subdivisions.

Is there a better way to go about this?

I am attaching the file.

About the image, I checked my code about 10 times to understand why it has those "lines" every 1 meter in the Z, and they already appear in the "rail revolution" component when it is visible, but in the "brep components" I can see the individual points along the rail curve.

I think this is what might be causing the brep to surface problem, but for the life of me I can't understand why the rail is not smooth and is "divided" into the 7 points instead of just one smooth revolution...

Thanks! :)