That's why I don't feel so bad for keeping my ancient RSD-12s that I built. They don't run like an Atlas, but they look right. The one problem with the old Model Power trucks is that they were geared high. Even with the old GSB "Tan Can" motors I installed, they have a rabbit start. I hook up a Proto 2000 SD-9 with them and it keeps them in check because the RSD-12s are kind of light.
I actually have a pair of Atlas RSD-12s and I find that their small discrepancy in overall length is not a big deal. Yes they used the RS-11 components, but it still looks like an RSD-12 to observers and modelers alike. I actually want to have a couple more like the existing pair.
I agree Blaine... Of course, my models will never see a RPM meet, but I'm alright with that. I'd love to have ANY RSD-11, 12 or 15, even if they're a little off. Show winners, no - but chunky looking, smooth running ALCos, absolutely!!
Carmine, CEO, Chief Engineer, and Bottle Washer- The Pacific Belt Model Railroad, est. 1975!