What would bend a full-size Amtrak passenger car into, basically, an L-shape?

[Ken Burch]

The image that most stays with me from the Philly derailment is this:

One of the cars was actually bent so badly it was nearly in the shape of an L.

For that to happen, what kind of torque would that car have to put under? How fast would it have to be traveling(and would it be within state and federal regulations to run a passenger train through an urban area at such a speed?)and would that sort of bending be caused by a direct collision with something or by the cars in fromt and behind that car swinging in opposite directions as the train left the tracks?

[malaise]

1. Hitting a bridge?

I heard someone suggest that one carriage hit a bridge - we'll see as the sun rises

[jberryhill]

2. Completely fact-free speculation with high probability of being wrong here:

Okay, on the basis of not much whatsoever other than years spent as a frequent rail commuter in Philadelphia, I have two working theories, having spent a full 15 minutes or so watching local news coverage last night:

1. Extraterrestrials

When something is not immediately explained, it is usually extraterrestrials. If they start talking about swamp gas or ball lightning, that will nail it down for sure.

2. Switching Error + Speed

That particular area has a number of switches to side tracks, as the route is shared among Amtrak, NJ Transit, and SEPTA trains. The switching and signaling system is archaic and requires multiple humans to do what they are supposed to do. A combination of high speed, failing to observe signals, and a switching error might, on the basis of my complete absence of any knowledge of the mechanics of rail switches or train coupling mechanisms, impart a significant torque on the train.

On edit:

Likely irrelevant support of uninformed speculation:



You see the curve and the multiple tracks there.

[mnhtnbb]

4. I suspect your switching error + speed is a very good guess.

We rode Amtrak from DC to Cary a few weeks ago. The conductor told us once
when we were stopped that we were literally waiting for someone to come and manually
throw a switch! Yikes. Doesn't give you much assurance.

[jberryhill]

5. Here's another view of the area

http://media.nbcphiladelphia.com/images/620*42/Frankford+Junction+Map.jpg

It's really something when you are on one of the regional commuter trains creeping along after being switched onto one of the side tracks when an Amtrak train comes by. The pressure wave sometimes pops the covers off of the ventilation system inside the train with a loud *crack*.

This was the last derailment at the same spot in 1943:

http://www.nbcphiladelphia.com/news/local/Another-Deadly-Train-Derailment-Happened-at-Frankford-Junction-71-Years-Ago-303557531.html

[n2doc]

3. Hulk Smash! n/t

[FSogol]

6. Huh? It is simple to bend what is essentially a hollow tube into a "L" Take a paper towel roll

and push in at ends. It is pretty strong. Now bend in into an "L" from the middle. Very easy. Now add speed, a collision, and a violent stop while mass behind you keeps moving forward. Very easy to destroy the car like that.

[dixiegrrrrl]

7. I just woke to the news....was there a fire also reported?

[Renew Deal]

11. Not that I saw or heard about

[AngryAmish]

8. Someone on tv said speed was a factor.

Too fast for the curve.

But anyrhing now is speculation and I am really not qualified to offer any advice.

[NuclearDem]

9. By God, someone get the chicken wire, we have a mystery to solve!

[Renew Deal]

10. Someone last night said it hit an electrical pole

[hobbit709]

12. Basic Newtonian physics.

Rail cars are not light. Factor in velocity and you have a mess.

[ProfessorGAC]

13. They're Also Not Strong On The Sides

The center of the side is the weakest part of the car. So, it would be like the crumple point on the front end of a car. Big heavy thing times deceleration due to impact on a weak part of the structure.

Same thing happen when the Amtrak train hit a truck at a crossing in Kankakee a few years back.

[JaneyVee]

14. E = MC2

[hobbit709]

15. Actually you start here

And then follow Newton's Laws.

[MannyGoldstein]

27. Irrelevant

There was no significant exchange between matter and energy.

[nadinbrzezinski]

33. Mope, not even close.

This is a Newtonian event, not a relativistic event.

[Fumesucker]

35. E=1/2 MV^2

Kinetic energy is equal to one half the mass times the velocity squared.

[snooper2]

16. you do know they are designed to be light to save on fuel costs

not like they are built like a Brinks truck LOL

[hobbit709]

18. Light is a relative term. Average weight for a passenger rail car is about 100,000 lbs.

[randome]

17. That's an easy one.

[hr][font color="blue"][center]Birds are territorial creatures.
The lyrics to the songbird's melodious trill go something like this:
"Stay out of my territory or I'll PECK YOUR GODDAMNED EYES OUT!"[/center][/font][hr]

[Ilsa]

23. Copied. Thanks! LOL. nt

[yuiyoshida]

36. loves me some

Gojira!

[Panich52]

19. One knowlegable on trains said passenger cars on Amtrak are lacking in side support

Cars were largely built in 70s and it dosn't take much to cave one in from the side. He referenced an accident where a truck broadsided such a rail car.

There are passenger cars w/ stronger side support but, of course, GOP cutting funds makes them less likely to be used. Even on a route highly utilized by politicians.

[Abouttime]

20. Lack of funding=GOP obstruction

The blame for this tragedy falls 100% on the repub senators and reps in congress! they have cut funding for amtrack repeatedly, now we see the results of their greed and short sighhtedness.
President Obama needs to hammer this home, we need infrastructure spending and the millions of jobs that will follow.

[yeoman6987]

29. The President can't. He signed the deductions.

Someone else might. Of course driving 50 miles over posted speed probably had more to do with it.

[catnhatnh]

21. Nano-thermite? N/T

[Brother Buzz]

22. Are we looking at the same Amtrak crash?

I see cars jacknifed, but not actually bent

[Ken Burch]

25. At the right of the picture, just slightly away and to the left of the still-linked line of cars

Not only bent, but completely crushed-in.

here's another angle of what i'm talking about:

[Brother Buzz]

34. Ah!

I later saw a photograph that showed an I-beam t-boned the car and bent the beam like a Sherman bow tie.

[Xithras]

24. Modern Amtrak train cars are built of pretty thin steel.

Many of the multiple deck passenger cars don't even have the heavy steel frames under them anymore that older passenger cars used. The design provides more passenger space and consumes less fuel, but they have all the rigidity of an aluminum soda can in an accident.

The cars are large enough that their overall weight is still high, so there's lots of potential energy being transferred in an accident. Lots of potential energy + lightweight materials = major structural damage.

As for what caused it... It's entirely possible that the train car simply dug into the dirt and came to a halt. If the dirt was soft enough to allow the car to dig in, nothing else would have been required. The momentum and potential energy of the cars still moving behind it would have been more than enough to crush it and rip it apart.

[peace13]

26. 100+ mph on a curve rated 50mph.......

....is gonna do some terrible things. So sad.

[jwirr]

28. Well we know that the train was traveling 102 mph. IMO that car may have been twisted between

the engine and the car behind it while they were still connected to each other or went flying end over end.

[pinto]

30. From what I've heard - hit a vertical bridge support girder, sideways, as it left the tracks.

[RobertEarl]

31. Pics confirm that

There exists sets of overhead bars every fifty feet or so over the tracks. Each overhead bar is supported by steel pillars, and one can see a missing pillar where the train went off the track. Another pic shows a pillar type piece of steel entrained in the car that is L shaped.

[Puzzledtraveller]

32. velocity.