A nullhot sparenull method for facilitating the seamless transition from a failed robotic mechanism to backup unit is provided. A spare robot is located inside a storage library on a section of rail (robotic track) from which it can be utilized on any rail layer in a multi-layer architecture. In one embodiment of the present invention, a motorized elevator assembly is used to transport the spare robot to the proper library level, which allows a single redundant robot to support multiple robots on multiple library rail levels. In another embodiment, a hot spare robot is used on each rail level and is utilized if needed on that particular level. In both embodiments, the spare robots are available for immediate backup without direct user intervention.