i would do a couple of things differently with her - first she would not have shoes on and second her ankles would be tied spread and fixed so that she would be facing the passing train. Just some thoughts to enhance the humiliation.
When I lived in Tokyo I enjoyed exposing my nude body to passing passenger trains in a small local park. On one side of the small park there were wooden benches where I would just lie naked in full view of the passing trains. On the other side of the park there was a low wooden fence that faced the train track. I enjoyed sitting naked on the fence with my legs apart so my cock was clearly visible to the train passengers.