Sliding rack is also known as mobile rack, it is similar to standard rack. It is considered a dense storage method. It requires fewer aisles and the rack rows move to create a lift truck aisle. Mobile racks are standard single deep pallet rack rows or back to back rows that are placed on to movable bases. Sliding rack is designed with minimal 6-in sections of back to back movable rack rows, one lift truck aisle, and at each end of these movable sections a single deep standard rack row. The sliding rack has a ratio of four - five pallets high to one deep. A sliding rack moves to the side and creates a forklift truck transaction aisle between the required rack rows. It provides high pallet position density and good accessibility. There is only one mobile aisle used to access several rows of racks. The location of the aisle is changed by sliding the rows of racks along guide rails in the floor. Moreover it is found in library racks.