If you are modeling the Santa Fe, they really don't cross very many impressive rivers. The Colorado at Needles, Ca is probably decent, but most will look more like dry washes with a trickle of water in the bottom if your lucky. I'm not sure whether you can find anything suitable on a commercial level. In addition, any river of size won't turn tightly enough to disappear behind the bridge. What would be the best bet would be if you could take a vacation to the area you want to model and do a little exploring to find that perfect river to get pictures of. The Santa Fe doesn't run anywhere near it; but if you ever get out to the Sedona, Az on vacation, I think the Verde River might make a perfect picture to make your own picture into a poster for a backdrop. I don't know if there is anything suitable in the Midwest. Your bridge isn't nearly big enough to cross the Missippi.
