A modular storage system for installation on a floor includes a plurality of carts. Each cart includes a base that generally has a length that separates opposed ends of the base, a storage structure that is operably attached to and carried by the base, at least three pivotable wheel assemblies, the wheel assemblies being operably attached to and extending below the base to provide a rolling surface adapted to roll on the floor, and at least one track follower mechanism that is operably attached to one end of the base and having at least a portion of which is selectively vertically movable to engage the track.