Push Back Racking
Is push-back racking FIFO or LIFO?
It is LIFO because the last pallet loaded into the front of the lane becomes the first pallet retrieved from that same front face.
Does the forklift enter the rack?
No. Forklift access is from a single front aisle; pallets are deposited into the lane from that aisle and the forklift never drives inside the rack structure.
What is the main engineering difference between push-back and pallet flow rack?
Push-back racking uses nested carts or shuttles on inclined rails for LIFO storage, while pallet flow rack is designed for FIFO movement with pallets advancing from the loading end to the picking end.
Push-back racking is a high-density pallet storage system that stores multiple pallets deep in a single lane using nested carts or shuttles riding on slightly inclined rails. New pallets are loaded from the front and push existing pallets backward; retrieval takes place from the same front face, providing last-in, first-out (LIFO) flow.
Push-back racking is a good fit when a warehouse or plant needs more pallet positions per square foot but still wants aisle-side access. Forklift operators work one front face, loading and unloading pallets without entering the lane. Each pallet placed on the outer cart pushes the previous pallets back on inclined rails; when the outer pallet is removed, the remaining pallets gravity-advance forward. This is practical for incoming raw material buffers, packaging materials, and finished-goods staging where the most recent delivery is the first to be issued. Because the lane stores pallets in depth, WMS slotting must record a lane-level location and align lot or pallet IDs to that physical sequence. Consistent pallet condition, load weight, and footprint keep carts moving smoothly, while the density gain reduces forklift travel and opens floor space near production or shipping.
Expiration or lot-control mismatch: The lane releases the newest pallet first, so perishable or date-regulated goods can sit buried while newer stock ships. Eventually the operator is left with expired inventory, spoilage claims, and compliance exposure.
Load and pallet incompatibility: Mixed pallet sizes, damaged pallets, or uneven loads stop carts from rolling and nesting cleanly. Lanes jam, loads skew, and forklift drivers struggle to seat the next pallet without striking the rack.
Throughput and maintenance issues: When inclined rails, carts, or rollers fall out of spec, gravity-assisted movement becomes sluggish or stops. Receiving and picking bottleneck at the face, and maintenance hours climb while throughput drops.