Looking online at descriptions of the trolley case, I can’t find anything placing me on the trolley. I think my version comes from Philippa Foot and I don’t remember how she says it. It’s been a while. I believe there was an accompanying case where one is piloting an airliner crashing into the center of a populous city. One has just enough control to steer for a suburb.   Perhaps I just ran the two together in my mind over the years.