In the terrain editor forum are posts documenting this current terrain I'm building with screen shots to demystify the process. Everything from the 1:1 art file laid out full size to map everything to cutting and sculpting terrain so no surprises with Hitech. Hitech has had months to review every screen shot and has made suggestions along the way. You are required to contact Hitech with some kind of mock up of your idea to get feed back. Then it helps to post screen shots and things you are developing which gives Hitech an opportunity to tell you no, or give you assistance or insights. He helped me with the bridges and now they work. He told me exactly "NO" when I put a 32,000ft wall completely around the out side of the game space to keep strat runners on the map. He is also kind about not dinging you for making rooky mistakes with the terrain editor.
I always direct players to Easyscor and the AvA terrain team for in-depth help on the minutia. They will not let you fail if possible and Hitech will give you advice if you ask him.
I wade into things because many of you are sharing as common knowledge misinformation about processes and how they work as your presumptions for how your wish list items will play out. Or you think Hitech will magically make it happen, which is not far from reality with programing.
In the case of AI trains, it's a neutral idea, it will be a giant PITA for a Melee arena builder to tweak into his terrain equally for three countries. Who did you think would put them into a terrain? It's like the wish for berms to hide tanks behind. Waffle can make them as objects that a terrain builder has to get down to a few feet from the ground and drop in. Then he will have to keep running a build, exiting out and going offline to drive around where he put them to see if they make any GV combat sense. If not, exit the game, back into the terrain editor and make a micro move a few feet of those objects. Rinse and repeat. What you see in the terrain editor inside of a 1\4mile circle is completely scale wise different than what it will look like when you drive around in that circle. There is still no guarantee after the terrain goes live that GV players will see any advantage in using that 1\4 area as part of their combat strategy. You also cannot build a terrain by committee if you ever want to get it finished, especially if your committee will not be there with you at your computer while you do all of the work. So yes, I don't have ESP so different players will not like various different things about my terrain. So what, at least it's a new terrain to have purse fights over.
The AvA terrain guys can tell you years of stories about the obscene number of hours it takes to build these labors of love, especially as they increase the numbers of their own custom objects they create for the AvA terrains.
This is why I tell everyone to build their own terrain to get exactly what you believe is your Aces High utopia.