Trains, trucks and barges are on the way back. Bustr and I are both working on MA terrains with them in and in doing so are helping HT to de-bug them.
If you want to see them in action set up a custom arena online and select "bearpit" as the terrain. This terrain has trains to all the strats except the cities as well as trucks to all the vehicle and airfields. The ports have barges running on adjacent rivers.