TEDW, yes I meant R2 = 1K of course, my mistake, duh. Anyway glad that is working for you.
I have my first few cars done using grj's roll your own modules with R1 of 12 ohms and R2 of 100 ohms. This gives an output range of about 12 to 100 ma. The cars are 15" so I am using 14" long led strips, with 21 leds per car. For a first run I have them set at 90 ma output, so just over 4 ma each, and they are quite bright. For now I like how they look, I may run them a while like that then crank them down a little. Time will tell.
In thinking about the photocell variable brightness idea, I guess it would be overkill and unnecessarily complex. Plus everytime the train went under a bridge or through a tunnel the lights would dim, which would look kind of odd. 
Rod
