Push Back rack systems use a dynamic cart-on-rail system in which deeper pallet loads automatically advance when the front pallet load is retrieved, they work by gravity, placing pallet loads on a series of nesting carts that run on rigid structural steel rails. This system allows you to store from 2 up to 5 pallets deep while retaining easy access to a variety of different products. Each level and lane is independently accessible and allows much more product storage than selective rack systems. Pallets are placed by forklift on nested carts riding on inclined rails. Each pallet is then pushed back by subsequent pallet loading, exposing the next cart. When unloading, the front pallet is removed, allowing the other carts to roll gently to the front. Gravity moves the pallets forward to the aisle on the carriages during unloading.