i have been following this idea on another site and here are some issuses they raised with real water usage:
1) shorts, plus humidity is not good for scenery), and partly because water does not "scale" properly.
2) Beside the fact that real water looks out of scale there's another "scale" problem - namely the deposit that builds up when water evaporates repeatedly. These are the minerals and whatnot in the water, and leave a whitish film behind. I suppose distilled water wouldn't have this problem,
3) I also tried the real water with the algae problem being the biggest deterren
i do not know about real water and model ho or n scale trains
check this link out they have ideas and stuff listed in more details
http://www.the-gauge.com/thread14787-us ... water.html
hope the owners of this site do not mind the cross post to another train site