Freight transport is divided into unimodal and multimodal transport. Unimodal transport uses one mode of transport (e.g., road), whereas multimodal transport uses at least two modes of transport with loading units being transshipped between them. During the transshipment process, the loading units (e.g., containers) can be opened, shipments can be temporarily stored, resorted and transshipped

In intermodal transport, which is a subtype of multimodal transport, goods are transported in one and the same loading unit via more than two modes of transport. In this process the closed loading unit is always handled as a whole.

In contrast to intermodal transport, Combined Transport (CT) is defined as a freight transportation system that integrates at least two modes of transport in a door-to-door transport chain, where pre- and on-carriage are kept as short as possible.

One variation of CT is combined road-rail freight transport. Along this transport chain, the goods are shipped by road in the pre- and on-carriage and by rail in the main-carriage.