If you have a backyard that slopes (is on the edge of a hill), you may wish to consider a vanishing edge (negative edge) pool, where one or more edges of the pool create the illusion of a horizon line (where the ocean meets sky). Sometimes, the effect is similar to that of water appearing to be suspended in air since the vanishing edge side of the pool remains invisible to an onlooker standing on the other side of the pool. The solution: PCS developed a “Rail Track Assembly” and unique tracking system that permits the installation of track on the vanishing edge side(s) of the pool without interfering with the vanishing-edge effect or the smooth extension and retraction of the cover.