This mod turns possible to players and AI build walls over trade routes. If you want a better looking, build gates on the walls placed on the trade route, so it will open when the travois/train passes by it.
Differently from another mods, you can build all the parts of the walls over the trade route (posts too!).
Installation: place the protoy.xml file on "Age of Empires 3/data/"
This mod works with The Asian Dynasties expansion pack.