The U.S. Military is considered the inventor of the first standardized shipping container

The CONEX box: a direct precursor of the container

Developed by the U.S. Army shortly after the end of World War II, the CONEX box can now be considered the forerunner of today’s conventional containers. It anticipated many of the container’s features and impressively demonstrated the practicality of a standardized container concept. Above all, its use in transporting and storing supplies and military goods during the Korean and Vietnam wars anticipated the subsequent rapid expansion of containers. Learn more about this box, its rudimentary precursors and the versatile ways in which it has been repurposed.

Of course people were thinking about standardized transport containers long before the 20th century. Back then, freight was packaged in wooden boxes, pallets, crates, barrels or simply in sheets. Loading and unloading these goods was labor-intensive, costly and slow.


Numerous historical forerunners

In the 19th century, British merchants largely used early, semi-standardized “containers” that could be transported by horses and trains. This could be considered a first attempt at multimodal transport, especially for bulky cargo such as ore and coal but also for bringing live fish to the towns farther inland. Then, in the early 20th century in England and the US, people started using “lift vans,” stable wooden crates with metal eyelets at the upper ends. The holes made them easier to load by crane, for example onto horse-drawn carriages. However, at first the lack of standardization inhibited broader usage. Although the lift vans became more popular once people had agreed on their dimensions in the 1920s, their success was limited by the rounded tops, which made stacking impossible.


The military as a driver of innovation

The next development step came, as so often, as a result of a conflict during war. Similar to pallets and forklifts, the ultimate refinement of these old ideas and widespread implementation of the container concept took off during World War II.
The U.S. Army began experimenting with containers at the start of the war to quickly deliver food and ammunition to the front lines and gain time during loading and unloading at the ports. They also wanted to avoid theft and transport damage during deliveries. They designed rectangular boxes with a stable steel frame, which proved reliable for shipping but couldn’t be stacked on top of each other. On the other hand, they did fit nicely on train cars, flatbed trucks and into ships’ holds. These boxes were optimized continuously, but the combat ended before anyone managed to design the first robust and stackable container that was worthy of the name.


Boost from the Korean War

In 1948, the time had finally come. The U.S. Army’s transportation corps came up with a “transporter,” a rigid, corrugated metal container that could carry slightly over 4,000 kilograms of cargo. It was 2.59 m long, 1.91 m wide and 2.08 m high, with double doors at one end and lifting rings at the four top corners. The Army started with only 67 units, but it was immediately clear that the “transporter” would be very useful, especially right at the start of the Korean War. For that reason it was further developed into the container system “Container Express” – CONEX – at the end of 1952. The size and capacity of the CONEX was roughly similar to the modified precursor it was based on. The system was also made modular, e.g. by adding a smaller unit with half the size. Up to three of these boxes could be stacked on top of each other and, thanks to their construction, they could protect their contents in any weather. The concept proved reliable in military use; at the same time, the inventor of today’s standard container, Malcolm McLean, was working on a “civilian version” on the other side of the world.

Versatile and practical: the CONEX box

Versatile and in demand in Vietnam

By 1965, the U.S. military had about 100,000 CONEX boxes and acquired another 100,000 by 1967. This was due to the increasing escalation of the Vietnam War and the need to adequately provide for the American GIs in South-East Asia. It was the ultimate breakthrough and the world’s first intercontinental use of a standardized, intermodal transport container. However, the containers reuse as originally planned during the Vietnam War was only partially successful. More than three-quarters of the CONEX boxes were shipped only once and actually remained in the combat zone. Because to the soldiers, the containers themselves seemed just as practical as the contents they transported. They were used as permanent storage options, formed temporary shelters in outposts and even served as makeshift reinforcements of defensive structures.


“Out of service” but still in use

As the scope of U.S. involvement in the war continued to grow, the armed forces turned to Malcolm McLean and his company “Sea-Land Services,” whose ISO container was already causing a sensation by this time. Again, the priority was to ensure a rapid supply for the U.S. military and the legendary transportation entrepreneur had no problem providing the required services. As the story goes, the decision makers were completely won over when McLean explained about the containers’ locks: this finally meant that they could effectively stop the rampant theft by Viet Cong sympathizers. Malcolm McLean’s company profited twice in this deal: after the troops were supplied, the empty containers were used to send back merchandise from Japanese ports to the USA. It was a win-win situation and at its peak, the deal was allegedly responsible for 40% of the revenue of Sea-Land Services.

Subsequently, CONEX boxes were replaced by the much larger ISO containers in emergencies, when large amounts of supplies had to be moved quickly. In 1991, for example, as part of “Operation Desert Storm” in the Middle East, about 40,000 commercial and military containers of both kinds were shipped.

Even with their now reduced scope, CONEX boxes continue to be used. By now there have also been further developments, such as the QUADCON, BICON and TRICON.  The term CONEX itself continues to be used frequently by the U.S. military, even to refer to the now familiar shipping containers according to ISO standard. And the “little box” is still a long way from the junk yard, since the military continues to find new uses for it: most recently, the U.S. Air Force succeeded in converting a CONEX box into a low pressure capsule to transport patients infected with COVID-19. Very clever!