Compare 4-Way vs 2-Way Shuttle vs Crane ASRS
| 4-Way Shuttle | 2-Way Shuttle | Crane ASRS | |
|---|---|---|---|
| Pallet accessibility | Every pallet location in the 4-way racking is accessible by all shuttles using transfer lanes and lifts | Locked to one lane until manually relocated | Full within its own dedicated aisle |
| Cross-lane movement | Automated using omni-directional 4-way shuttles | Manual — craned or forklifted between lanes | Not applicable — one crane per aisle |
| Storage density | Very high — no dead or blocked lanes | High, but limited by single-lane access | Very high, aisle-for-aisle |
| Typical investment level | Moderate — scales incrementally | Lower entry cost per lane | Highest — dedicated crane per aisle |
| Scalability | Add shuttles, lifts and racking lanes over time | Add shuttles per lane; relocation stays manual | Fixed once installed — capacity is not incremental |
How 4-Way Racking Works — Shuttle Plus Cross-Transfer
An integrated system of reliable 4-way shuttles, lifts, racking, and a smart fleet management software accesses every pallet location for their automated storage and retrieval. One fleet of shuttles can work a whole block instead of a single run.
Pallet presented to in-feed conveyor
Forklift or AMR presents the pallets to infeed conveyor, pallet goes through dimension, weight and pallet label scanning check before entering the 4-way system.
Lifts move pallets between levels
A pallet lift moves the pallet between levels through a seamless transfer between chain conveyors and 4-way shuttles.
Automated pallet put-away and retrieval
The 4-way shuttles transfer the pallets to (or from) lifts to the pallet locations via transfer lanes. Every pallet location is accessible by one shuttle fleet. The target pallet is retrieved and presented to out-feed conveyor through the system.
Powered by an intelligent fleet management software
The Warehouse Control System software intelligently links to the WMS and ERP, plans storage locations, manages shuttle fleet and lifts in a user-friendly interface.
4-way shuttles travels through the transfer lanes to access the pallet locations; the lifts moves the shuttles and pallets across levels.
Full Location Access — Every Pallet, Any Lane
Because the shuttle can leave its lane, no pallet position is ever sealed off behind another load. Every location in the block stays reachable from every aisle it serves.
Total pallet accessibility
No pallet is permanently behind another — the shuttle can always reach it from another aisle.
FIFO or LIFO by layout
Design the transfer point positions to support first-in-first-out or last-in-first-out picking.
No blocked or blind lanes
Removes the “stuck behind a full lane” problem that limits 2-way shuttle and double-deep bays.
Retrofit-friendly
Options available to convert your traditional 2-way radio shuttle racking system to a smart fully automated 4-way system.
Every lane reachable from every aisle — no dead stock.
Built for High-Throughput, Multi-SKU Operations
Multiple lanes can be worked in parallel by one shuttle fleet, so 4-way racking scales from a single aisle trial to a full lights-out block as volumes grow.
Parallel lane operation
Several lanes can be loaded, cycled or picked at once instead of queuing behind one shuttle.
Scales toward lights-out
Add shuttles and lifts over time without redesigning the racking frame.
Integrates with your WMS
Lane, depth and transfer instructions can be driven directly from your warehouse system.
Flexible design to suit your operation
A conveyor system tailored for customers pallet movement needs can be seamlessly integrated with the 4-way racking layout.
Multiple lanes, one shuttle fleet — sized to your throughput.
Safety, Compliance and Efficiency Engineered Together
Structural & Seismic Design
Every layout is engineered to AS/NZS 4084 for load rating and seismic performance, with footings, bracing and beam locks specified for your site and zone.
Transfer Point & Guarding
Cross-transfer rails, column guards, meshed transfer lanes and pallet stops protect stock and structure at every lane and aisle interface
Inspection & Compliance
Scheduled structural and shuttle inspections, damage reporting and load signage keep the system compliant and safe long-term.
Designed, engineered and installed to AS/NZS 4084
AS/NZS 4084 is the joint Australian/New Zealand standard for steel storage racking — covering structural design, load rating and seismic performance. Every Southward 4-way layout is specified against it, with shuttle and transfer-point safety interlocks assessed for the equipment your project uses.
Deployable Across Every Warehouse Type
Space Efficiency
Cross-aisle travel removes dead lanes, lifting pallet positions per square metre beyond 2-way shuttle.
Compliance
CE certified 4-way shuttles. Racking engineered to AS/NZS 4084 with NZ seismic requirements.
Maintenance
Southward Warehouse Automation provides local service with quick turnaround; stocked with critical spares for the 4-way shuttles and racking components.
Suits sites across every industry Southward serves
Horticulture Coolsores, Dairy, Food & Beverage · 3rd Party Logistics (3PL)
Controls, WCS/WMS & System Intelligence
Intelligent control at every level. PLC and sensor I/O at the shuttle and transfer-car level, WCS/WES orchestrating multi-shuttle movement and lane sequencing, and integration with your WMS, WES and ERP to drive put-away rules, FIFO/FEFO rotation and retrieval priority – with every movement recorded for audit and SLA compliance
Frequently Asked Questions?
Not Sure Which Storage Solution Fits Your Site?
Every warehouse layout is different. Book a consultation and we’ll assess your site, pallet types and throughput needs to recommend the right storage solution — 4-way shuttle, 2-way shuttle or a hybrid approach — for your operation.
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