Amtrak derailment near Philadelphia

Used as the worked example of the Five Whys root-cause technique. Tom walks through alternative causation hypotheses — texting, drugs, rock-dropping from overpasses — that were being explored in the press at the time.

Take the Amtrak derailment. Why did the train outside of Philadelphia a couple weeks ago derail? Too fast. It was going too fast into a curve. Why was he going too fast? I was just reading the paper this morning, and on page two they said he wasn't texting on a cell phone. He didn't test positive for drugs. Originally there was a question of whether someone had dropped a rock from an overpass, which happens all the time. Teenagers go to overpasses and drop rocks on top of speeding cars. They kill people. It's not a smart thing to do, and in busy areas they build big fences so the teenagers have to throw overhead.