For adding on to a tape automation system, a base unit is provided having at least one tape cartridge magazine having a plurality of tape cartridge receiving locations, a tape drive, a tape cartridge pickup which transports the tape cartridge from a tape cartridge receiving location after extraction to a tape drive in a first direction, a tape cartridge pickup guide along which the tape cartridge pickup travels, and an elevator system which moves the cartridge pickup guide in a second direction perpendicular to the first direction. The base unit has a removable cover. An add-on unit is provided having at least one tape cartridge magazine having a plurality of tape cartridge receiving locations. The cover is removed from the base unit and the add-on unit is placed on the base unit. The base unit elevator system is used to retrieve tape cartridges with the cartridge pickup from the add-on unit cartridge magazine and also from the base unit cartridge magazine.