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Solution Spotlight: SpanTrack Lane Carton Flow Rollers


What is Carton Flow?

Carton flow, also known as flow racking, roller racking, and gravity flow racking, is a dynamic storage solution that can dramatically improve space utilization and order picking efficiency within warehouses, order fulfillment centers, retail stores, and manufacturing facilities. Carton flow tracks are conveyors - either roller or wheel-based - that are cut to a size that will span the length of a bay of pallet racking. Conveyor tracks create storage lanes within pallet racking designed for increased material flow, better space utilization, and improved efficiency throughout a facility. These storage lanes use gravity to flow products through the rack to allow for streamlined replenishment and order picking.

Most carton flow comes in a variety of options like light-duty, standard-duty, and heavy-duty; steel and aluminum rollers; plastic wheels or steel skatewheels. In this article, we are going to explore all things carton flow rollers as we dive deep into The Original Carton Flow Track: SpanTrack Lane!

UNEX SpanTrack Carton Flow

UNEX-Spantrack-Lane-Carton-FlowWhen it comes to storage, solutions like SpanTrack carton flow help order fulfillment operations, retailers, logistics providers, and manufacturers maximize space utilization and accelerate processes. SpanTrack is ideal for facilities with case picking or each picking operations, and manufacturing facilities looking to improve efficiency with flow-through workstations, lineside storage racks, and manufacturing supermarkets

UNEX SpanTrack is a patented solution for warehouse storage, order picking, and part picking. SpanTrack is unique because it drops into existing pallet rack, making installation a breeze. SpanTrack carton flow provides the most surface contact with items. Unlike older-style carton flow and plastic wheel rails, SpanTrack carton flow tracks prevent hang-ups that disrupt flow, ensuring products move seamlessly to the point of pick.

SpanTrack Benefits

  • Versatility: SpanTrack can be added to any new or existing pallet rack. No shelving or intermediate support is required. 
  • Superior Flexibility: SpanTrack provides the flexibility to store products with a wide variation in size and weight. 
  • High Capacity, Durability: SpanTrack takes the abuse of active warehouses and assembly plants. 
  • Unrivaled Flow: SpanTrack provides maximum carton support and up to 300% more product contact than plastic wheel rails, resulting in better flow, fewer hang-ups, and increased throughput.

Get The Definitive Guide to Carton Flow Storage and The Ultimate Order Picking Checklist. Download the guide today!


All About SpanTrack Lane Carton Flow Rollers

SpanTrack Lane is one of several UNEX carton flow solutions. Efficient, durable, and dependable, SpanTrack Lane carton flow rollers are highly configurable with different flow options, capacities, and end treatments to meet the needs of any operation. Guard rails, slow-down strips, swing stops, and more accessories can be added to optimize performance based on your needs. Plus, all SpanTrack carton flow tracks come with a comprehensive seven-year warranty. 

SpanTrack Lane Key Features

  • Provides 300% more product contact than plastic wheel rails
  • Integrated label holder system
  • Interior notching to save vertical space
  • Freezer/cooler rated to below zero 
  • Optimized for product stacking
  • Ideal for case picking
  • The original carton flow track

Like all UNEX solutions, SpanTrack Lane is engineered to order. What does this mean? It means we offer full, free engineering support on all projects and will work with you and your preferred material handling reseller to create solutions that are optimized to be no more or less than what you need to maximize space and increase efficiency across your operation. This saves you headaches, time, and money on your project. 

To provide these tailor-made solutions, UNEX offers many ways to outfit your SpanTrack Lane to meet the unique needs of your operation.


Selecting the Correct Track Width for your SpanTrack Lane

SpanTrack Lane is available in 6 different widths at varying capacities. The width of the items you are flowing will be the primary factor in determining which SpanTrack Lane width is right for you. Cartons can overhang lanes up to 3" on either side and still maintain proper flow. So, there is a big opportunity to increase space utilization by selecting the narrowest width possible without compromising flow. Below is a handy chart that will help you determine the best SpanTrack Lane track width based on the maximum width of what you’re trying to store and flow:

SpanTrack Lane Width Guide

SpanTrack Lane Flow Options and Capacities

SpanTrack Lane is offered in 3 main capacities or “series”:

  • 98 Series: Our 98 series rollers are our lightest capacity tracks. 98 Series SpanTrack Lane carton flow rollers are .75” inches in diameter and can be made in aluminum or steel. 98 Series SpanTrack Lane is rated starting at 35 lb. per linear foot. If your application does not require high-capacity tracks, choosing this light-duty solution will provide the maximum space savings. In other words, if you can get away with a light-duty carton flow roller, take advantage of the cost and space savings! To learn more about light-duty carton flow solutions and when it's appropriate to choose this option, check out this related reading: Advantage of Light-Duty Carton Flow for Order Fulfillment
  • 99 Series: Our 99 series carton flow rollers are considered standard-duty and are typically the most common, as this mid-range option is a sweet spot that has become a go-to for many operations. Like 98 series rollers, 99 series SpanTrack Lane is also .75” in diameter and can be made in steel or aluminum. 99 series rollers are rated starting at 50 lb. per linear foot so they can take more of a beating than our lightest-duty carton flow. 
  • 100 Series: Our 100 series carton flow rollers are our heaviest-duty carton flow solution. 100 series SpanTrack Lane rollers are 1.38” in diameter and are made of galvanized steel with bearings. Our 1.38” roller (also known as our “JRS” roller) is the same heavy-duty roller used in our most rugged gravity conveyor solutions. These rollers span (pun intended!) the test of time. 100 series roller lanes are rated starting at 100 lb. per linear foot.

For a more detailed look into our light, standard, and heavy-duty carton flow roller options, you can refer to this handy chart to help determine capacity per linear foot depending on the length of your tracks. This and more can be found in our SpanTrack brochure!

SpanTrack Capacities

SpanTrack Lane End Styles

Once you’ve determined which capacity suits your needs, you’ll want to consider your SpanTrack Lane end style options. End styles refer to how the tracks are situated within your pallet rack beams. Will they sit on top of the beams or nest between beams using hangers? Do you need your tracks to overhang your structure? When considering end styles that are right for you, you’ll want to think about the best way to integrate SpanTrack with your existing pallet rack beams to maximize space. But you will also want to consider the needs of your application. For example, if you are creating bays for each picking, you may opt for a knuckled end treatment that will angle the track toward the pick face. This maximizes space utilization while increasing visibility into split cases where workers are picking eaches. 


Here is a quick walkthrough of our SpanTrack Lane end style options, what each is for, and when to use them:

  • Low Profile: Low profile carton flow tracks nest between beams on hangers for maximum use of vertical space. Low profile tracks can be used for full case or each picking applications, and are perfect for racks with pallet storage above.
  • Low Profile Knuckle: Low profile knuckled tracks can be made in 12", 16", 20", and 24" lengths. At the pick face, a 20-degree angled front end tilts cartons forward for increased efficiency in each pick applications within the rack structure.
  • Hangerless: Hangerless tracks do not require the use of a hanger to sit within your pallet rack beams. With hangerless SpanTrack, an adjustable length track sits on the ledge of step beams in the front and rear, keeping the face of the beams clear.
  • Pushback: To create pushback racks using SpanTrack Lane carton flow rollers, notched tracks can be placed on top of your step beams with stops on the front and rear of the tracks. Pushback carton flow is ideal for applications where items are loaded and picked from the front of the rack.
  • High Profile: High profile carton flow lanes rest on the top of rack beams. High profile tracks can easily be adjusted for various contouring options. Because these tracks overhang the structure, you can significantly increase storage capacity. So, if high profile tracks are feasible for your application, you can take advantage of the extra storage space the increased length of the track provides.
  • High Profile Knuckle: High profile knuckled tracks also rest on top of rack beams but they also incorporate a knuckled end treatment. High profile tracks can overhang structures up to 24" with a 20-degree angled front end for increased efficiency in each pick applications. Increasing storage capacity and visibility? Now we’re talking!
  • Add-On Pick Trays: In addition to various track end treatments, UNEX also offers pick trays that can be added to your SpanTrack Lane.
    • Pick Trays come in 12” and 15” depths with 2” lips and can be up to 96” wide.
    • Adjustable Pick Trays come in 18” and 24” depths and can be made with 2” or 4” lips.

Selecting the Correct Roller Centers

What the heck are roller centers?! Simply put, when someone mentions carton flow “roller centers” they are referring to the spacing between each roller. As product increases in length, additional space can be added between rollers to optimize flow. Other factors like humidity, condition of boxes, bottom surfaces of totes, the weight of your boxes, and more need to be considered when choosing the right roller centers for your SpanTrack Lane. Having closer centers can increase flow reliability with these other factors. 


SpanTrack Lane roller centers are offered in standard 1”, 2”, or 3” spacings. Below is a quick breakdown that can help guide you on roller center selection based on the minimum length of the objects you’re flowing:

  • 1” Roller Centers: 1” roller centers offer very minimal spacing between rollers. We recommend a minimum carton length of 4” and up to 8” max for flowing objects on 1” roller centers.
  • 2” Roller Centers: 2” roller centers offer a moderate amount of spacing between rollers. We recommend a minimum carton length of 8” up to 12” for flowing objects on 2” roller centers.
  • 3” Roller Centers: 3” roller centers offer a significant amount of spacing between rollers. We recommend a minimum carton length of 12” for flowing objects on 3” roller centers.

Centers Guide

SpanTrack Lane Accessories and Options

UNEX offers a full line of accessories and options that set SpanTrack Lane apart from other carton flow rollers. Whether you need infeed guides, impact zones, or slow down strips, you can rely on The Original Carton Flow Track to keep your processes and profits flowing! 

SpanTrack Lane accessories can be used to further tailor the solution to your specific needs. UNEX offers SpanTrack Lane accessories to ease replenishment, strategically slow down product flow at critical places in your tracks, and more. SpanTrack Lane accessories include:

spantrack-carton-flow-accessories-slow-down-plateImpact Plate: The impact plate is a sheet metal plate that goes on the front or rear of your SpanTrack Lane to strategically slow product down. These plates create friction for more surface contact to reduce impact on your carton flow tracks. Impact plates can be used to reduce impact when loading products and can also be used for slowing down product flow at the pick face. Impact plates simply snap on over your carton flow rollers or wheels.

spantrack-carton-flow-accessories-impact-zoneImpact Zone: An impact zone is a dense area of rollers that are typically made of steel and placed at the rear of your SpanTrack Lane. Impact zones are built directly into your carton flow tracks. Typical impact zones sit at the rear of the lane and consist of a 12” area of steel rollers that are on 1” roller centers. The rest of the track consists of 2” or 3” roller centers. The dense area of rollers in the rear of the track provides more surface area contact, taking the abuse off the loading process where impact is higher.

spantrack-carton-flow-accessories-ramp-stopRaised Pressure Relief Ramp Stop: A Raised Pressure Relief Ramp Stop is a sheet metal plate that easily snaps onto your SpanTrack carton flow rollers at the front of your bay. It is used to lift up the front of your product so it does not become wedged against the front beam or end stop. Ramp stops are effective in slowing down material flow and relieving back pressure from the foremost carton on longer spans.

spantrack-carton-flow-accessories-slow-down-stripsSlow Down Strips: Slow Down Strips are one-inch wide sheet metal strips that easily snap onto SpanTrack carton flow rollers. They create friction to slow product down before it reaches the front of the rack to prevent product from crashing into the front beam or stop.


spantrack-carton-flow-accessories-lane-infeed-guidesInfeed Guides: SpanTrack Lane Infeed Guides are metal guides that attach to the outer channels of SpanTrack roller Lanes. These infeed guides allow employees to place product in the correct locations when loading product from the rear of a SpanTrack bay. SpanTrack Lane Infeed Guides easily attach to the side channels of your SpanTrack lane with a nut. Fixed guides force product to be placed in the correct location for optimal flow.

spantrack-carton-flow-accessories-lane-guard-railGuard Rails: SpanTrack Lane Guard Rail are steel side guards that keep products in their designated lanes. Guard rails are used to contain product on roller lanes. They easily bolt to the side channels of your SpanTrack Lane and keep product flowing straight from the rear to the front of your bay.


spantrack-carton-flow-accessories-swing-stopSwing Stops: A Swing Stop is a stop that is placed on the front or rear of your SpanTrack and can be positioned up or down to facilitate product loading and unloading. Place the stop in the up position when product is flowing and being stored. Place the stop in the down position when picking or loading product. Swing Stops can be added to SpanTrack Lanes and are installed directly onto your tracks.

Related Reading: SpanTrack Carton Flow Accessories and Options

Discover the Difference with UNEX SpanTrack Lane Carton Flow Rollers

As the maker of The Original Carton Flow Track, UNEX is uniquely qualified to be your trusted advisor on all things carton flow rollers. SpanTrack Lane is a first-of-its-kind product that has stood the test of time, offering customers the following benefits (and more) for over 30 years:

  • Increased storage capacity and pick facings
  • Full-depth storage
  • Safe, ergonomic picks
  • Easy restocking and FIFO stock rotation

Contact our team of SpanTrack Lane experts today to see if this solution is right for your next project!

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