A group of children were playing near two railway tracks, one still in use while the other disused. Only one child played on the disused track, the rest on the operational track.
The train is coming, and you are just beside the track interchange. You can make the train change its course to the disused track and save most of the kids. However, that would also mean the lone child playing by the disused track would be sacrificed. Or would you rather let the train go its way?