I am designing the steel bunton sets in a mine shaft servicing a personnel/material cage, and trying to determine the appropriate lateral loads on the shaft steel for design. I have 3 applicable standards (SANS 10208-4; AS/NZS 3785.6; ISO 19426-5), all of which contain the same equation for determining the lateral load. This equation requires you to determine the "proportion of the conveyance mass effectively acting at a slipper plate", an equation that requires the variable h1 & h2. All standards define this variable using the same language: "the lever arm distances of the relevant slipper plate loads with respect to the relevant centroidal axes". I'm having difficulty determining the correct distance to use for this variable. No pictures or illustrations are offered as to what distance exactly this variable is referring to. Has anyone had any experience with this equation, or seen a labeled picture of how to determine this variable?