Swap body

A change in structure ( also swap- swap, swap body, WAB, Exchange suitcase in Switzerland and alternating loading container or short WELAB ) is a replaceable carriers, which - can be separated from the carrier vehicle (truck ) - similar to an ISO container. For use in combined transport it must be equipped with devices that allow an envelope on the web ( UIC 592-4 ). This is achieved by gripping edges which are located on the underside of the interchangeable body. Cranes in container terminals have this special gripper arms, which includes interchangeable bodies laterally and can be lifted. As the ISO container swap body on the intended for their transport trucks, trailers ( carriages ) and freight cars are by pins (so-called twist locks ) connected. The locking standard size of a swap with 5820 mm corresponds to that of a 20-foot ISO container, so that swap and ISO containers can be transported on the same carrier vehicles without retooling. An advantage of the interchangeable body against ISO containers are its range width and the flexible options in dimensions.

There are different container classes:

( - Length 7150 mm, 7450 mm, 7820 mm EN 284) for articulated trains especially the C container with 16 tons total weight are suitable. These containers four support legs are folded down on the sides, then the vehicle can - be lowered and moved out under the parked construction - by venting the air suspension bellows. This form is commonly referred to as a swap body.

Another variant of the C- containers are stackable swap bodies. These are part of European standardization in the preparation; they exist only in the length of 7450 mm.

More hoppers are the A containers. They are suitable for transport on the saddle chassis, have no supporting legs, have a total weight up to 34 tons and a length of up to 13,670 mm ( with a tunnel- shaped cutout at the front of the bottom, for receiving the reinforcing bars of the semi-trailer to its coupling).

The unique design feature of the supports is that they are in a recess on the side bottom edges of the WAB and thus along housed within the WAB WAB width and above the lower edge of the direction of travel while driving. At the booth they are - first a piece pulled out laterally parallel, then folded at a hinge down, fixed with a brace and at least highlighted on erdweichem underground with a stable block - by hand. The lateral pull by about 20-30 cm is also laterally enough space to eject the load-bearing chassis.

In order to maneuver the trailer of a articulated train under a WAB, it takes practice, precision, patience, and also space. However, train trucks have front usually a shunting with which the trailer is zurückrangieren geometrically easier and with direct vision.

Unlike ISO containers, swap bodies are more suitable for road and rail transport.

There are interchangeable bodies with tarpaulin roof, curtainsider, closed box bodies and a number of special bodies. Similar to megatrailers there is also a variant with an internal height of 3 m. These so-called jumbo swap bodies are equipped with a pop-top, make optimum use of the volume.

For the transport of liquids in cylindrical containers are steel frame in focus ( Liquitainer ) and can then be treated as interchangeable bodies.

Historical Development

The emergence of modern alternating structure began in the early 1950s. At this time began, the U.S. freight forwarder Malcom McLean to develop exchangeable superstructures that could be transported by truck, both on the road and by boat. His ideas led eventually to the world today used ISO containers, which are no longer an integral part of the international transport. In Europe in the early 1950s began the German Federal Post Office with the introduction of the so-called Weber- container. These were standardized container package for road and rail vehicles, which were placed in a precharged state on the transport vehicles. Both McLean's ideas as well as the Federal Post Office it was mainly a matter of finding a way to speed up the handling of goods and to avoid long downtimes for the vehicles used.

In 1971, the German forwarder Dachser developed then the swap, a swap body with fold-out support legs. While a crane or special truck to change the structure was still required in the previously common swap bodies, now enabled this development to depose the complete change structure without any additional aids from the truck or take. Since the swap as opposed to ISO container is a European development, the dimensions of which are adapted to the dimensions of euro pallets. The C- container according to EN 284 feature in the version with 7150 mm length over 17 EUR pallet spaces, with 7450 mm over 18 and with 7820 mm over 19 parking spaces. Nowadays, there are also cases and refrigerated box swap bodies, which have a double-decker charger. Such equipment makes it possible to better use at correspondingly low pallets, the volume of the interchangeable body and loaded into 2 layers, without having to stack the pallets thereby directly.