CHINA TRAILERS manufacture Nicolas model SPT (Self Propelled Trailer), Drive axle units can be operated independently or assembled into any combination. The units overcome the need for ballasted heavy duty prime movers, which improves manoeuvrability and flexibility of use. Optimum applications include the on-site movement of bridge units, pre-assembled piperacks and structures requiring adaptable support conditions, but not the high carrying capacity of Self Propelled Modular Transporters (SPMT’s)