AI dropping off cars

I have looked high and low but I do not see any mention of how to get the AI train to drop off cars?
I see many good tutorials about setting up Player Trains and picking up and dropping off cars but not so much about the AI trains doing this?
I would SURE appreciate someone pointing me in the right direction.
I have "Googled" my fingers sore looking and looking and looking.
Thanks so much!
Greg
I see many good tutorials about setting up Player Trains and picking up and dropping off cars but not so much about the AI trains doing this?
I would SURE appreciate someone pointing me in the right direction.
I have "Googled" my fingers sore looking and looking and looking.
Thanks so much!
Greg