Abstract: A compound railroad track wherein the head rail is easily replaceable without replacement of the supports, which comprise two extruded mirror-image L-shaped members, periodically spaced U-shaped separators, and a base plate, all suitably bolted and welded together.

Abstract: An improved sliding door composed of articulated strips in which the novel features are a high guide containing a rotating vertical wheel that supports two adjacent strips and a rotating horizontal wheel that follow a curved track. Additional features include a floor guide that contains only straight segments that are not joined together the corner and a base guide attached to the articulated strips that travels within the floor guide without touching said floor guide during stationary or ordinary operation of the door.