A lift structure of a rack storage system including a pair of vertical post, a pair of guide rail portions stacked one on top of the other, a mounting brace, and a mounting platform attached to the pair of vertical post. The mounting brace includes an adjustment mechanism to adjust an alignment between the pair of guide rail portions fastened together by a clamping plate. A load handling station is secured to the mounting platform to support loads transported to and from the rack storage system, wherein the load handling station is located by locating a position of the mounting platform.