If any of you are into vehicles, mostly HO, there is a great website that has thousands of trucks, trailers, cars and detail parts. The name is truckstophobbies1-87.com. The owner's name is Steve Beekhuizen and he is extremely helpful. Yesterday, when the pup trailer idea hit me (posted on another thread), I called him. Please see the following link. https://www.truckstophobbies1-87.com/ He had the part numbers memorized for the proper dolly for the front of the rear trailer, and the hitch for the back of the front trailer. He added them to an existing order so that I did not have to pay shipping twice. It is fun just browsing the site. I have bought over a dozen trucks from him.