Automatic storage apparatus particularly adapted for storage retrieval of information-bearing documents is described. The apparatus is particularly adapted to enable precision high-speed storage and retrieval operations in extensible storage systems. An outer frame securely supports an extremely rigid inner frame via shock mounts and an equalizing apparatus. The equalizing apparatus permits slight movements of the inner frame for facilitating precise colinear interconnections of a plurality of modular cabinets comprising the storage apparatus. A traveling elevator is precisely mounted on the inner frame for movements through a plurality of the connectable cabinets. Several embodiments are shown.