Vehicles is an ongoing project.
Yes the train works.
Got a 20 player DogFight map now as well

(that's Planes not Dogs ... lol)
Also got new weapons, including, mines and flamethrowers.
MohRadiant is the map editing app, get it from
http://www.mohaa.ea.com
And no it's not all you'll need

... but it's a start.
TMT TheModdingTheater
http://www.modtheater.com is where i mainly hang out now, and you'll find masses of info about modding mohaa on there.