Logistics of Intermodal Transport

 

Wharfs and ports always fascinated me and made me wonder how the huge ships, cranes, trucks and most of all the containers are stacked like building blocks? What are the processes of container ports like this? How are containers unloaded? Where do they go, and what happens next?

 

We’re going to find out if containerization is as orderly as it seems, or if there is some chaos in these neatly stacked rows – and what opportunity and challenges automation has brought to the shipping industry.

 

Containerization has changed the world. Previously ships would hold multiple smaller loads all jumbled together into a cargo hold – now the sorting of cargo into containers is done before the cargo is loaded.

 This allows ships to have a greater efficiency when loading and unloading cargo. But is has also brought new challenges for organization, as gigantic ships dock in large ports and need to unload hundreds or thousands of containers at a time.

 

Container terminals are hubs of intermodal transport. That means that the containers are switching modes of transport, from a ship, which travels on the sea, to either road or rail. Containers can also be moved by air – but this is not usually the focus of container ports. Switching modes of transport is not quite as simple as loading a cargo container from a ship onto a truck – multiple steps and organizational challenges are involved before the container rolls out of the freight yard.

 

 First – the container must be unloaded from the ship. This is achieved with huge gantry cranes that are able to lift the several tones of container and its cargo. Cranes can be hinged to allow for passage of large ships beneath, or can be fixed, to reduce airspace being taken up.

Freight terminal cranes are either semi-automated, or fully-operated by a human, and some ports have a mix of both. Cranes connect to containers by their corner fittings – which, like most other parts of a container are standardized throughout the world, by the International Organization for Standardization.

 

Another international standard is the unique identifier number which helps to keep track of each container. The containers are typically loaded onto Terminal Tractors.

These funny-looking trucks are meant for short-distance haulage, in order to get the container from beside the ship, into the storage yard where the containers wait to be picked up by a truck or a train.

In order to move containers around a storage yard, and onto trucks and trains, there are several options for machinery – 2 of the most interesting are reach stackers and rubber-tyre gantries.

 

Rubber-tyre gantries have wheels, and are cranes that are able to fully straddle containers. Larger versions may run on tracks, rather than tyres, and can straddle multiple rows of containers. Reach-stackers have a long arm that can easily be used to stack containers several rows deep, or to negotiate them onto semi-trailers and rail cars.

 

Every step of the process described so far has the capacity to be fully- or semi-automated. And in fact, at some of the terminals at the Port of Rotterdam in the Netherlands – they all are, at least partially.

 A crane operator remotely operates the gantry crane via computer software that unloads containers from a ship. The container onto a fully automated terminal truck which drives it to the storage area to be unloaded by an automated stacker crane.

This is one area where logical planning augmented by computers can provide a huge benefit. Knowing exactly what date and time a container needs to be picked up, a computer can plan the most efficient way to stack containers. This ensures the container isn’t buried too deep in the stacks when its time comes to leave the yard, reducing the number of operations required to access the required container.

 

 

There are still some storage yards around the world that used a paper-based tracking system. For some of these yards, this means that containers are simply stacked according to when they are brought in to the storage yard – so that when the time comes to take them out again, they might be at the bottom of a stack of containers.

 

 Like many other industries, computerized automation provides some unique benefits over human-operation, such as accuracy of repetitive tasks and logical planning of efficient processes – until something goes wrong and many hours are spent trying to troubleshoot and fix the issue.

 

 For now at least, humans maintain the advantage of adaptability over fully-automated machines. Automating a container port is very expensive, but ports implementing this technology hope to gain benefits such as increased productivity, and increased safety. Of course, even at ports where automation exists, humans are still employed to oversee and maintain the machines and rectify problems as they arise.

As automation continues, concerns about job-losses are always on the forefront of debate. There is also the real cost to society with a smaller income tax revenue stream to fund things like roads and rail – the very things the transport industry relies on.

 

Ideas have been put forward for a robot tax to help subsidize this loss. However these problems are dealt with in the future, it is clear for now that the inevitable march of the machines will continue. Perhaps the solution lies balanced somewhere in the middle. With human operators and overseers able to quickly adapt to unforeseen problems, with machines performing dangerous tasks for us, and with organizational systems augmented by computerized calculations.