We have it pretty much reverse engineered, both from other of our cars and from crawling under D&S and other cars with cameras and tape measures, we're just looking for all available info and trying to do a period setup for the straight air to modern air configuration, the way it was done back in the day. To show people what they were, we have built a Miller Hook coupler for one end of the car from the engineering drawings. Another of our static cars has link and pin on one end with knuckle coupler on the other to show people the safety advances.