In addition to philosophical questions, the Trolley Problem is also a good tool in psychology to study human ethical reasoning. It turns out that people's intuitive responses vary quite a lot based on details that seem like they shouldn't make a difference. If I'm remembering correctly, I believe that a lot more people say that they would divert the trolley if they imagine that they were observing the situation from a gantry high above the tracks, rather than in close proximity to the person who would be killed thereby.