Push-Back Racking for LIFO High-Density Storage

Push-back racking uses a series of nesting carts (typically 2 carts for a 3-deep system, 3 carts for a 4-deep system, and so on) that stack on top of each other at the front of the lane when empty. Each cart rides on inclined rails attached to the pallet rack beams, sloped at approximately 3/8 inch per foot toward the pick face. When a pallet is placed on the front cart, the operator pushes it back to place it behind the front position, nesting the carts together. Each subsequent pallet loads behind the previous one. When the front pallet is retrieved, the remaining carts and pallets flow forward under gravity to the pick face.

Cart capacity is a critical specification. Standard push-back carts are rated for 2,500–3,500 lbs per pallet position for 2–3 deep systems. Heavy-duty carts for 4–6 deep systems with heavier loads require structural-grade cart components and heavier rail sections. The incline angle and cart design must be carefully matched: too shallow an incline and pallets may not return to the pick face reliably; too steep and pallets arrive with excessive speed. Properly engineered push-back systems from Unarco, Mecalux, or other reputable manufacturers account for these variables across a range of pallet weights.

The operational advantage of push-back versus drive-in is significant in multi-SKU environments. In a drive-in lane, only one SKU can occupy the lane (any retrieval requires taking the front pallet, which may not be the desired SKU unless the lane is dedicated to a single product). In push-back racking, the front pallet is always the most recently loaded, meaning a single lane can contain multiple pallets of the same SKU loaded at different times, or in some warehouse configurations, different SKUs if LIFO rotation is acceptable for those products. The front-only access from a single aisle also means no sacrificial aisle is needed at the back of the system, recovering that floor space for additional storage.