Mike,
Not trying to talk you into anything, but if you really want scale, you might want to consider 2 rail. That said you likely want mostly 40 foot box cars (which meant 40 foot inside dimension) which were common with steam. Atlas used to offer several different numbers of the same car, and they are as nice as any, barring some brass versions. I would look for them and depending on what type of track you use, you could run 2 rail cars and ditch the lobster claws and pizza cutters. I would recommend you get on you tube and look some of both kinds of layouts before you choose. Here is a good 2 rail video with a real nice 8X16 2 rail layout included:
https://www.youtube.com/watch?v=HAjrZ_t6w28
PS: No such thing as semi-scale....it's either scale or Not.
Simon
