Disclosed is a load handling system including: a trailer capable of being hitched to a towing vehicle and/or to other trailers in order to form a conveyor train. Wheels and a shaft support a chassis equipped with a loading and unloading module for a load-bearing dolly. The loading and unloading module includes a conveyor defining a first incline for positioning the dolly, whereby the dolly is no longer in contact with the ground and is held in position on the trailer, and a second incline, the second incline having a symmetric position with respect to the first incline. The conveyor enables loading and unloading of the dolly on the first side of the trailer and on the second side of the trailer.