Stacking containers as optimally as possible at the terminal or depot minimises the number of unpaid handlings. In order to most effectively position containers, the crane operator and/or reach stacker driver needs information about the subsequent steps in the container’s journey. Based on these steps, the crane operator or reach stacker driver determines the stack position. However, when the terminal is busy and the stacks are pretty full, even the most experienced crane operator or reach stacker driver may struggle to keep track of all activities. Depending on the operator’s experience and on how busy the terminal is, they may not always select the most optimal stack position. To make the allocation of stack positions more consistent and transparent, so-called stacking rules are used. In this article, we explain the digitisation and automation solutions we can provide when it comes to implementing stacking rules.
Unique stacking rules per terminal
Each terminal site has a different infrastructure. Furthermore, various types of cranes are used. A stacking plan is drawn up based on logic and differs from site to site. The working method of a crane operator or reach stacker driver can also vary from one terminal to the next, depending on the terminal’s objectives and any agreements with the customer (such as maximum truck dwell time at the terminal, for example, or customers calling containers on-demand). So, the stacking rules at a terminal depend on factors such as infrastructure, site layout and objectives. The characteristics of stack positions also play a role here; two examples are stacks equipped with reefer racks to accommodate reefer containers and stacks specifically geared to the storage of containers carrying hazardous goods. There are various ways in which this process, the allocation of stack positions, can be optimised and automated. Again, the most suitable optimisation for a specific situation differs per terminal. In the following paragraphs, we will discuss three different optimisation options for implementing stacking rules we currently use for our customers. Towards the end of the article, we will also discuss additional optimisation options to keep unpaid handlings at the terminal to a minimum.
Optimisation option 1: Automate stacking rules using planning boards
Different types of stacking rules apply to inbound and outbound truck traffic. The locations which are assigned to export containers delivered by truck are established in one set of stacking rules, for example, and the stacking or retrieval locations regarding the delivery and collection of empty depot containers in another set of rules. These stacking rules are digitally recorded in our planning boards. The Modality system ‘reads’ these stacking rules and communicates the optimal location. Because the planning boards are linked to the ‘Gate control module’, the Modality system can already indicate the recommended stack position the moment the truck enters the terminal. As a result, the counter employee can advise the driver of the most optimal stack position when they report to the counter or gate. The planning boards basically run in the background. When stacking rules are amended, terminal employees can easily implement these changes in the planning boards.
In practice, planning boards are mainly used to assign stack positions to containers delivered and collected by truck. Of course, planning boards have just as much added value for allocating the most optimal stack positions for rail and maritime containers.
Optimisation option 2: Automatically generate an advised stack position
A second option for optimisation entails automating the stacking rules that the crane operator or reach stacker driver uses when selecting a stacking position. By this, we mean the decision-making rules that are made every day based on human insight. We inventory and categorise these decision-making rules and next incorporate them within an algorithm. This algorithm considers various parameters such as current stack occupancy, collection date, container type, cargo type, etc. The current position of the crane can also be a possible parameter within the algorithm. If this is the case, then an interface between the crane’s PLC system and the Modality system is needed. With this interface, the Modality system continuously receives the exact location of the crane as well as all lock and unlock actions. The Modality system inventories all information and generates up-to-date stack position advice based on the parameters within the algorithm.
Automatically generate an advised stack position
Optimisation option 3: the generation of automated handling orders
In the previous example, the crane operator or reach stacker driver sets their priorities regarding the tasks they must perform that day. For example, they start with unloading a barge or truck, whereby the Modality system offers advice regarding the most optimum stack position. An even greater degree of automation is possible as well. For example, the Modality system can automatically generate ‘work orders’ or automated handling orders. Here, the system not only proposes a stack advice but also determines the priority/order of the movements to be performed. Consequently, the system is leading in determining the order of all activities the operator or driver must perform daily. While the system still plays an advisory role in other situations, it is guiding in this specific situation and the operator or driver no longer has any influence on selecting the stack positions.
Other terminal optimisations: graphical stack overviews and reading stowage plan data
When a terminal is crowded and has a high occupancy rate, it becomes more difficult for the operation to keep track of all activities. Our graphical stack overviews offer support in this. The name says it all: the various stack positions are displayed visually in the graphical stack overview. The graphical stack overviews make it possible to filter on specific outbound journeys or unloading addresses, for example. Since the graphical stack overview also uses different colours, containers with the same unloading date can be visually displayed in the same colour, for instance. This gives both terminal (yard) management and crane operators and reach stacker drivers a convenient tool that supports them in manually determining the most optimal stack positions. If the Modality system is linked to the crane’s PLC system, the operator no longer has to change stack positions during movements within the crane range manually; furthermore, any changes are automatically displayed in the graphical stack overview as well.
Another option for optimisation is the automatic reading of stowage plan data into the Modality system via EDI. This allows the crane operator to see the specific loading location of containers on the barge or determine the position of containers that need to be unloaded from the vessel.
The ideal situation when allocating the most optimal stack positions
The most optimal or ideal (automation) situation for determining stack positions varies per terminal. For example, generating automated handling orders is only possible if an interface with the crane’s PLC system is present. If the terminal mainly uses reach stackers to stack the containers, one option could be to transmit the current location to the Modality system by means of an interface with OCR software in combination with GPS. Is full automation of the stacking rules not yet possible? Then the graphical stack overviews constitute a useful tool for keeping track of containers and manually determining the most ideal stack positions. Depending on your own situation, you can choose the optimisation options that suit you best.
Would you like advice on the automation of stacking rules and the other options we provide regarding terminal optimisation? Our Sales Department will gladly tell you more about previous customer case studies. Please contact our Sales Department directly via sales@modality.nl or +31 (0) 180 531 035.
