Large Train Station

I am soon beginning construction on a Train station. I want it to be a grand one and not a replica. An original. It will be either 6 or 9 feet long with a boarding platform. In the process of designing one I noticed that it will require a great deal of windows. This brought me to a few big questions.

How hard would it be to make a mold for window casings and doors?
What material should I use? plaster or a plastic?

Has anyone attempted this method or is it a waist of time and is there a better method?