Great work, guys.
Jerry, I really like those lights at the gas station.
MLW, nice cars and engines, but I really like the looks of the brickwork on that building.
Mike, looks like you're going to have a really nice train set there. The smoke from that engine on You Tube looks better than most American smoke units I've seen. How are things out on the desert.
Jeffrey, looks like you'll have nice, dilapidated coaling towers when you're done.
Gramps, I guess you could try the old cotton smoke trick like Bob said. Get some cotton, paint it dirt color, paste a few small rocks and weeds on it, and glue some behind each tire. It would probably look pretty convincing.