What I don't get is why you allow alcohol on the train in the first place. On a recent trip to the Nevada Northern, we happened to be on the same train as a group of German (or some other European country) tourists who loved the train and loved their beer, although a bit too much. It made the ride quite unenjoyable, and uncomfortable for many families with small children.
While I can understand that railroading, even tourist railroading, is a hard business to be in, and every little cent counts, I think that if some trains temporarily discontinued the alcohol sales during events that would draw such families as the disappointed post writer above, more money would be brought in.
Another idea would be to have, on certain days of the week, the higher-class cars open to minors as long as there is appropriate adult supervision, and advertise them as such. I for one would prefer one of the "real" passenger cars over the converted gondolas, flatcars and boxcars and would go out of the way to book a train for my (future) children on such days if this idea is implemented.