Great. The last one isn't nescescarry. Im doing a map that REQUIRES being very large, and the trains are transportation.Curves round corners, yes. Just do curved path_tracks
Can be ridden on, yes as well. Just have a platform players can stand on
Can be built on, no. Since the train is moving (I assume it will be), then the buildings will move off and float in mid-air.
@Acegikmo: the problem is, that the buildings wont be moving with the train, they will stay where they are and float in the air.
It should be possible to make you able to build on it.
Using enable/disable on a trigger that's filtered to only affect buildables, that parents them to the train.
I just tried this out. I can post the test map here if you want to.
It's set to only attach engineer buildables which does not have the name "attached".
After attaching the buildable, it changes the name of it to "attached", so the trigger won't trigger again on an entity that's already parented.