Most model railroads are effected by humidity of some sort, wehter from environemtal encroachment to an improperly set air conditioner, humidifier, etc. Get a dehumidifier that is 3-5 times over sized for the sapce you railroad occupies. Dependant on the space you you layout occupies (i.e. a separate room or area) try to isolate it from other areas of your dweliing if possible (a separate room with sealed doors-you can apply weather stripping to any regular door with a little ingenuity). This makes the dehumidification process more energy efficient and effective. Take care of your de-humidifier. Too dry, simply leave a flat pan of water out somewhere (if you have pets, other disturbances, etc. leave a vessel out that they cannot get at). You can humidify your space through other methods but this one seems to work best for me. Whatever works for you.
As for accelerating drying times for paint, gliue, etc. a heat gun (preferrable one of lower wattage or fully adustabel settings can help. I use a heat tool made for embossing plastic-like materials for the scrapbookingnhobby. You can use any safe source of heat, really. Heat gun, space heater, hot surface, whatever works for you particular applications. The low setting on any hair dryer works well also.
-Maxwell R. Holmquist