Thanks to everyone who has contributed to this thread and for keeping it going. I hope you will continue to post examples of your work and/or your thoughts, comments and questions here moving forward...a lot of really nice work (and great ideas!) have been shared so far! It would also be great to add some new contributors along the way...everyone is welcome here!
I haven't had time to work on any new 3RS (or any toy train-related) projects over the past couple months or so; however, I was looking through a photo disk recently and found a folder containing some pictures of the very first two freight cars that I added Kadee scale couplers to. I suppose I can say that this is where I got started with "3-rail scale"...