To my knowledge they haven't been introduced to AH III yet. And there was nothing 'AI' about them, they just rolled a set route every 10 minutes. Artificial Intelligence would at least indicate some degree of ability to react.
Didn't realize they might not be there. Although I could swear I can recall seeing barges since AH3, I could be wrong. When things happen doesn't particularly stick in my mind most of the time.
They may not be AI, but what would the AI difference be between a train and a bomber mission? It is going along a predetermined route and it will gun at enemies.
Wiley.