"If I take him he will find ways after we get home to get out and drink." If you don't take him, HE WILL FIND WAYS AFTER YOU GET HOME TO GET OUT AND DRINK. Whether you take him or not is a moot point. He can, and will, get out and drink if that is his desire. I think this is an area where you are still attempting to exert some control over his addiction.
It's great that you are not going to drive him to the train. That is certainly a positive step that will benefit you and your kids. Now just let him drink if he wishes. Should he start shooting his mouth off, go to another room, drive to the store with the kids, go visit family or friends. A drunk without an audience soon looses some of his steam.