Guys I'm trying to make myself a car that has both Microtrains coupler and the old style coupler I'm using a gondola which I weighted and figured because of the low center of gravity would be a good choice for this type of car. My problem is that the micro coupler fits so loosely on the pin that it flops around if I had a washer that fit the post it might help but the one they give does not fit. I've tried all the combos that came with the coupler kit and it still keeps derailing.It is an aurora trix car. Any advice????