The Superlink flatbed semi trailer is also called superlink flat deck trailer, Mongolia interlink flatbed trailer, Mongolia double semi trailer, interlink flatbed semi trailer, and a few other names. It refers to a special combination semi-trailer that is used for over limit transportation of large equipment and is attached between the lead vehicle and the trailer to increase the number of vehicle axles. This design and structure is in responding to oversize transportation and weight-based charging policies. There are usually three forms in perspective of axes: one line two axes, two lines four axes, and three lines six axes.