Abstract: A wheeled dolly is provided having a fixed coupler which permits the dolly to rigidly connect to the end of the cantilevered reach of a wheeled trailer. The dolly and trailer can be connected together to form a trailer having a reach extending between spaced-apart sets of wheels.

Abstract: The present invention is comprised of extensible piston cylinders which extend between first points located on a trailer and second points located on a gooseneck which interconnects the trailer to a tractor. The gooseneck and the trailer are rotatably coupled to one another at a common pivot point and the common pivot point, the first points and second points are arranged relative to one another such that as the piston cylinder is extended or retracted the gooseneck and trailer are respectively raised or lowered relative to the ground. The gooseneck is arranged so that it substantially encloses the piston cylinders throughout their entire range of travel thereby protecting them from damage. In addition a locking apparatus permits locking the piston cylinders to both the first and second points to present rotation of the gooseneck relative to the trailer. Thus the gooseneck and trailer can be removed from the tractor as a single unit.