Imagine that 5 people are trapped on the rails and the train comes speeding towards them and will kill them all in a few seconds. You have the choice to switch the rail key and direct the train to another track. Unfortunately, there is one person trapped on this other rail which will be killed if you switch the key. The question is, will you switch the key to save the 5 people? Think of this answer first
Now here is another test. These 5 people are still trapped on the rails. There is no key for you to switch. Instead, you stand on a tall bridge right above the rails. There is one man with you. If you drop this man outside the bridge he will fall on the tracks, the train will definitely kill him but the driver will stop the train and the 5 people will be saved. This is a trickier question, will you push this man to his death to save the 5 people?