Deconstructing Accidents

Accident assessments consist of examining a series of potential factors and ruling them out, and if not, what role the factor played. It can get complicated. A factor may or may not be the single competent cause of the accident. It may be a contributing factor. It may be dependent or independent.

In the immediate Amtrak scenario (Amtrak train 188 derailed Tuesday evening, May 12, 2015, en route from Washington DC to New York just north of downtown Philadelphia), based on the information I’ve seen, and I’ve been looking at this closely, I can speculate on some potential factors. Mind you, I have no basis to arrive at a conclusion of causality. This is merely an exercise geared to look at some pieces of the puzzle.

I am adding the latest potential piece: the possibility that a projectile hit the train. See:

Amtrak Train Possibly Hit Before Wreck

At a news conference on Friday, Robert L. Sumwalt, the safety board official who is leading the investigation, said an assistant conductor had reported that she believed she heard a radio transmission in which an engineer on a regional line said his train had been struck by a projectile and the engineer on the Amtrak train replied that his had been struck, too.

Mr. Sumwalt said that investigators had found a fist-size circular area of impact on the left side of the Amtrak train’s windshield and that they had asked the Federal Bureau of Investigation to analyze it.

Starting with known facts:

The train was traveling at 106mph as it entered a 50mph curve and derailed. The train had been accelerating and the engineer applied the emergency brakes only seconds prior to the crash. See, Here’s everything we know about the crash of Amtrak 188:


  • Stress:

“The derailment culminated what had already been a difficult day for him [Bostian].”

Tuesday afternoon, before the accident, Mr. Bostian was driving an Acela Express train from New York to Washington when the electronic signals malfunctioned, forcing him to carry out a long series of safety procedures, including slowing the train…Mr. Bostian was able to pull safely into Washington using the signals he could see on the trackside, but he was 30 minutes behind schedule.”

  • Fatigue:

“Because of the delay, Mr. Bostian only had an hour of rest, most of which was probably taken up by switching trains, filling out paperwork and doing equipment checks…”

  • Projectile:


If verified, what role – if any – did this play?

Likely ruled out:

  • Reportedly, toxicology (of the engineer, Bostian) was negative.


  • Reportedly, the train had no malfunctions.


Also, reportedly, the trip had been uneventful up until and shortly prior to the crash (an assistant conductor believed she heard a radio transmission in which the engineer replied that his train also had been struck by a projectile).

By now investigators know the weather conditions, light conditions, conditions of the tracks, and conditions of the signals (and other things I am unaware of).

The overall equation considers 1) Human factors, 2) Machine (train, switches, signals, guardrails tracks, etc.), and 3) Environment (weather, visibility, earthquakes, flooding, etc.). I’ll add a 4th) Other/Unexpected: a car stalled on the tracks; kids throwing things at the train; a projectile hitting the train; criminal acts; food poisoning; gas/toxic exposure; etc. This includes Unknowns (factors not known and that we may never know).


As I see it, the main hurdle is the 106mph speed of the train that slowed down to 102mph at the moment of derailing. And that only an hour or so after Bostian successfully arrived at Washington, D.C. in control of an Acela, did he assume the control of another Amtrak train, Train 188.


How do you explain this?



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