Stacking Shipping Containers Efficiently: Truck, Train, and Sea

Shipping containers are stacked in a manner that ensures stability and safety, similar to how empty-calorie junk food boxes are organized in warehouse storage. This process involves specific techniques and equipment to prevent containers from falling during transportation. Whether on trucks, trains, or ships, the stacking protocol follows stringent rules to minimize the risk of accidents and damage.

Stacking on Ships

For containers stored below deck, the process is straightforward. They simply sit between the container guides. However, for those above deck, more sophisticated methods are employed. Locking devices are placed between the fittings on the upper corners of the lower container and the lower corners of the upper container. These devices provide both tensile and compressive coupling, ensuring that the containers cannot shift or fall.

Diagonal tensile cross ties are also used across the ends of the container stacks to add additional stability. Ship operators take extra measures to minimize any heel or rolling motion of the vessel. These precautions are necessary to prevent containers from becoming unbalanced or shifting during transportation.

Stacking on Trucks and Trains

Two containers are never stacked directly on a truck. The typical container height is around 8 or 9 feet, and a chassis height of 3 to 4 feet brings the total load height to approximately 11 to 13 feet. Given that the federal highway design clearance for bridges and overpasses in the USA is 16 feet, it is rare to see trucks with two containers. If such a sight is encountered, there will likely be a chase truck with equipment to clear any hazards.

Containers on trucks are secured to the chassis using corner locking twist locks. These locks fit into sockets at each corner of the containers, ensuring a secure connection. On trains, it took some time to develop low-slung flatcars capable of holding two stacked containers. Railroads faced similar height limitations to highways, so two containers are not typically stacked on a railcar. When such arrangements occur, the bottom container is secured to the flatcar with twist locks, and the top container is secured to the bottom container with twist locks in the four corner castings.

Securing Containers

Twist locks are essential for securing containers on trucks and railcars. Each container has sockets at the corners, and a twist lock pin is inserted to lock the containers together. This process is crucial for preventing container movement and ensuring safe transportation.

Understanding and following these stacking and securing protocols is vital in the logistics industry to ensure efficient and safe transportation of goods. Whether on land or sea, the proper arrangement and securing of shipping containers help prevent damage, accidents, and delays.