I didn't do this job, but I saw your question. The divider track is probably a Kirsch ripple fold track mounted to the ceiling. I can tell from the drapes that they have a Ripple fold header ( Ripple fold Headers have a "wave" appearance. They are great because they use the least amount of fabric and they have the smallest stack back.) Another inexpensive idea that I did for a divider in our basement was an Ikea ceiling mount track with the panels. See picture below.