I own 2 cars with the new truck design. One is the new milk car with the hidden uncoupling tab. The other is a camera caboose with the ugly thumb tack. I tested both cars last night and found the caboose with the ugly thumb tack actually works to connect it to my existing fleet. In addition, the coupler is the same height as my other couplers. The coupler fits loosely into other trucks and will close fairly softly and with out issue when mating into other trucks. The new truck design with the hidden tab, droops badly and does not work with my existing fleet. It will not close and I almost have to really force it to fit with my existing fleet. So it would appear that the new truck design can work if you have the thumbtack version. The hidden tab version of the new trucks is a bust and does not work.