I used a couple of types on my track, they are both made of plastic.
This type comes from the local pizza place, they place it in between the pizza and the cardboard box they come in 12"x12" sheets.
I'll be replacing it with the black fencing material.
The black material was once used to line freezer cases where I used to work. They were going to throw it out so I ask if I could have it. I've had it for years.
I used solid strand wire to secure the fence to the posts. The horizonal rails are made from coffee stirrers hot glued into place
The posts were made from a store display stand that held hanging packages of product and that once again were just going to be tossed out. Bolt cutters made quick work of cutting them to size.
Window screen does look good for HO scale fencing but it's a bit off scale for 1/32.