Screen cap is what I am using as guard rails. I purchased it at Home Depot. It's very flexible . I bought a 16' square piece of square molding and cut it 1 3/4" pieces to use it as a guard rail(s). Now you need to find the perfect "Watkins Glen" blue to paint the rails.
I was at The Glen in 2016 when the had the 50th. anniversary of the Trans/Am series. It was awesome. I took some of my slot cars with me and took pictures of them together.