A transport system for a storage and retrieval system having an array of storage levels, each storage level having respective storage areas, the transport system including a vertical conveyor having a frame and support shelves movably coupled to the frame, each support shelf being configured to hold one or more uncontained case units in predetermined areas of the support shelf, and transfer vehicles disposed on respective ones of the storage levels, the vertical conveyor having a conveyor to transfer vehicle interface configured to transfer the uncontained case units substantially directly between the support shelves and the transfer vehicles for transport to the storage areas in substantially one transfer vehicle picking operation.