: These include lowboys, step decks, and removable goosenecks (RGN) . They are engineered to transport oversized cargo like heavy machinery or military gear.
: These are the gold standard for heavy commercial and agricultural use. A gooseneck hitch is designed for pickups and flatbeds, offering a towing capacity of up to 30,000 lbs and a tighter turn radius than standard bumper hitches.
If you are looking for information on high-capacity, heavy-duty hauling equipment—which might be the "substantial" trailers you have in mind— Heavy-Duty Trailer Types