GEF,
I'll keep that in mind - good idea. 
One quick tip I've discovered is that too flat is no good. This area of the layout is on my list for improvement since it has flats that are no thicker than the front wall itself. As you say, that makes achieving a sense of perspective difficult.
If you can at all spare the extra few inches needed, vary the thickness of the flats from building to building. If you have no more room, at least extend the upper floors out over the tracks a little. It will add lots of visual interest.
Also, break up long stretches of flats with some over-the-tracks feature such as this stone overpass. It will create more opportunity for some interesting scenes to avoid the monotony of nothing but flats. In the first photo, a simple bridge is installed to carry a street across the tracks to accomplish the same thing.
Jim
