We have a sliding door in the lounge with the usual track at the top.
The bottom of the door does not have a track of any sort but has a groove running centrally along the bottom edge which runs over a small block of wood or nylon to stop the door from being moved out of line vertically.
The block is placed adjacent to one of the door jambs and is always covered by the door itself. The door travel is limited by a rubber door stop screwed to the floor in line with the block.
Hope this helps if I'm not too late?