A swap body is a type of intermodal container that can be swapped from a truck chassis to a railcar. This swapping is accomplished through lifting the container while supporting its bottom. Swap body dimensions are made in conformance with the International Standards Organization (ISO), and are typically 8 feet (about 2.4 m) wide, with varying lengths.
These shipping containers have foldable legs to support the containers in-between the two transport modes. Swap body transport is commonly used in Europe. A swap body both weighs and costs less than standard shipping containers.
Other names for swap bodies are cargo containers, freight containers, or storage containers. Swap bodies differ from ISO containers in that the tops may be open. They cannot be stacked on top of each other, due to differences in the strength of the walls and top of the swap body.
Swap bodies are part of the intermodal transportation system. The standardization of a swap body allows economical rail shipment to be paired with the accessibility offered by truck transport, using a container that can easily be moved from one mode of transportation to another. This configurability allows shippers to service remote markets that are not accessible by rail, but are accessible by roads.
A typical journey of a swap container may begin by mounting it on a truck chassis at a swap body facility in a city. The semi-trailer then delivers the swap body to a rail depot, where it is swapped again. From there, the container will travel by rail, then be transferred to a truck chassis that will deliver the goods to the final destination.
Malcolm McLean, a truck driver from the U.S., is credited with inventing the shipping container in 1956. This innovation revolutionized the movement of international freight, decreasing the costs and time to load docked ships. The latest innovation in swap bodies are containers designed to be portable living facilities, which are useful for off-site work projects.
One concern with shipping containers is the possibility of criminals hiding dangerous or illegal materials, including fissile material, inside them. Since it is tremendously difficult to thoroughly search a tightly packed container that may have travelled through many countries, governmental authorities cannot possibly inspect each one for the presence of dangerous materials. Knowing this has led to public fears of terrorist attacks. To prevent unauthorized placement of items in a swap body container, it is becoming more common for swap bodies to have a hard surface on top, instead of a fabric-type covering.