STORAGE SYSTEM

The present invention provides a storage system (1) comprising a storage grid structure (104) having a top rail grid upon which container handling vehicles (200,300) work to store and retrieve storage containers (106) in and from storage columns (105) beneath the top rail grid, wherein the storage system comprises multiple transfer rails (110',111') forming a horizontal transfer rail grid (5) arranged at a level below the top rail grid, at least one transport vehicle (19) operating on the transfer rail grid, a picking/stocking station (8) for picking/stocking items between a storage container (106) and a packaging box (24), and an unloading/loading assembly (23) for unloading/loading packaging boxes containing such items, the transport vehicle (19) is arranged to move upon the transfer rail grid (5) in two perpendicular directions and comprises a carrier platform (20), wherein the transfer rail grid is arranged to allow access for the transport vehicle (19) to transport one or more packaging boxes at a time between the picking/stocking station and the unloading/loading assembly (23).