Bottom track

Thanks for posting. This looks like a track with recessed grooves for convex rollers. If that is correct, see our 23-240 and the other-sized variants I have listed on this page. A track with the overall shape like yours is no longer made; but so long as the distance between the grooves matches, as shown below, I think this can work for you. Take a look and let me know if you have further questions.

Profile view of sliding mirror door bottom track