Hi!
Yes, WIA used a simplified command system that reflects the style of the era. So no division, no corps, no "real" armies... and off course no railroads
WIA just uses normal stacks.
Another big difference: no supply forwarding! Feeding your troops on the wilderness is not and easy thing (and pushing supply carts around the forest and mountains isn't either!
Even if the game system is the same, WIA and AACW campaigns have a very different feeling because of the changes done on the engine to better represent the different historical situations.
A great thing IMHO
