People mover wagon suspension

I saw this set up for a people mover recently. It allows very easy installation of a modest suspension system on a 4 wheel wagon frame. I have been looking for something like this. But the person who had this on his people mover couldn't tell me much. He said it was an Amish company that made the parts and he thought the word "Pioneer" was part of the company name. Does anyone have any knowledge of where these parts can be obtained?

How fast do plan to pull your wagon? We run a half dozen people mover wagons built on old wagon gears (no suspension). The wagons operate along unimproved dirt lanes at 5 - 6 mph without difficulty. So long as the tires are not inflated rock hard the passengers’ ride is actually quite comfortable.