The modular trailers come in different modular units that include 2, 3, 4, 5, 6, and 8 axle models. The maximum load per axle is up to 40 tons. A larger number of axle lines means that the modular trailer has a higher loading capacity.
Self-propelled modular transporter (SPMT) are used to transport heavy cargo, which in most case is more than a hundred tons. The special vehicles are also widely used to carry over length goods that other heavy haulers cannot transport.