I would just make it a 0 movement, which recieves +1 movement from factories/harbors whatever. Once you put it into a sea zone its stuck, so there isn't much reason to put it there unless you intend to finish building it that turn
I discovered the 0 carrier cost thing a long time ago (I think it was version 1.4) so hopefully it isn't changed in the future
Yes but that system has shown to have a lot of problems and its probably why I never got to releasing that ww1 map.
I was trying to avoid having trains themselves on the map, to reduce micromanagment and simplify things a bit. But Ive found I really didn't like the resulting feel that i got