You look uphill into a very long railway tunnel and see five men working in the middle of it. You see two of them stand up, hearing something at the far end of the tunnel. “It’s a train!” one of them shouts. “Run!”
The train appears in the distance, outside the far entrance of the tunnel. Next to you, there is a button on the wall that you can push to collapse the scaffolding that is over the far entrance. You can’t see the scaffolding, since it’s on the other side of the tunnel, but an indicator beside the button tells you that one man is working on it. You know that if you push the button, that man will fall to his death and his body will stop the train from going into the tunnel. Whether you push the button or not, you’re safe, since you’re outside the bottom of the tunnel and you can easily move aside.
You see the five workmen, now running down the tunnel as fast as they can. You know that they cannot get out. They are too much far from you, and the train will speed up as it goes down the steep slope.
There was an accident like this many years ago. The bodies of the men in that accident were crushed so badly that they were unrecognizable. You know that each of the five men you see in the tunnel will meet the same fate unless you push the button.
Do you push the button?
[Clarification: Assume that the train is empty. (Maybe it was poorly secured and rolled down the hill.) The only people affected in the situation are the people on the scaffolding or in the tunnel.]