I was on my facebook page, and it gives page suggestions that you might like. This time it showed me "Paper model terrain". I went to it to check it out. The guy makes buildings, terrains, bridges, and sets for "Battle Tech war gaming". He posted a link to all the models, and there are alot of them. They are free to the group, but anybody who comes across this page can also see the link, so I guess anybody can download them. I think you could use these models for all kinds of things (Rail Road, dioramas, and what ever). Here is the link to the models http://www.sarna.net/files/media/cardstock/
Here is some pictures of the models.
Here is some pictures of the models.
