I run a heavy haul transportation company. These trailers are common in our field. You have a truck, "jeep" (the short trailer hitched to the truck), the lowboy trailer with a "stinger" on the back. The stinger has a pivot point on it, but when backing, they lock it straight with a hydraulic or manual pin. In essence, the whole rig pivots like pulling two trailers. Thus, to get it to go right, you steer right. Go left, steer left. Because it is a long trailer and the short jeep is up front, it's not as hard as you would think to an experience driver. Especially since he started with it straight and all he had to do was to keep it straight.