Note: Vehicles are not to scale.
Because of their operational characteristics, freight transportation modes have different capacities and efficiency levels. While trucks are the mode that has the least capacity, they have a level of flexibility (speed and door-to-door services) unmatched by rail, maritime, and fluvial transportation. Intermodal capacity in TEU for trains and trucks depends on the type of container being carried, with a 53-foot container, the equivalent of 2.65 TEU. Air cargo transportation capacity is more complex to assess since about 50% of the global air cargo is carried inside the bellyhold of standard passenger planes. Further, older passenger planes are converted into cargo planes to extend their commercial life. For instance, a 747 passenger plane can carry 8 to 12 metric tons in its bellyhold, and these planes are being retired, with some converted to cargo-only services. A dedicated 747 freight plane can carry 100 metric tons or more depending on the freight density and range.