Great looking scene, T! I've always wanted a trestle like that...
There was an article in a recent Model Railroader about model photography. It discussed the lighting, and I applied those techniques somewhat to my picture taking. Essentially, you have one light above the layout, one directly on the target area, and another highlighting the spots missed by the other two. By varying the distances of these lights, you can get different effects.
I've also found that the backdrop is essential in getting a good photo. It has to provide enough reflection so that the darker foreground scene stands out.
And, of course, you could always take the layout outside...but that might cause more problems with washouts...
I not a photographer. I don't even play one on TV!