A few remarks: The CSX train hasn't been an unmovable concrete wall. Its movement of 15' as well as the damage to the CSX lead unit has dissipated part of the crash energy.
On the Amtrak train locomotive as well as cars used up energy as the broken car shows.
In European passenger trains all cars have their own crumple zones. The first unit has to dissipate 75% of the crash energy the remaining cars 25% of the total of 6MJ. Besides using up the crash energy the CEM elements must be designed to limit the average deceleration in the cab to 5g and the maximum to 7.5g.Regards, Volker
Shadow the Cats ownerThis is a modern car hitting a wall at 120mph. This should give you an idea of the forces involved in a crash.
That's cute (cue Gene Wilder as Willy Wonka meme) but it gives you no idea of the forces involved in a head-on railroad collision where the following train pool-cues the head end, as here.
The automobile only has to dissipate its own momentum ... which is enough to disintegrate its flimsy structure. Watch what happens to it if you run 10 or 12 loaded semitrucks nose-to-tail right behind it into the wall at 120mph, then come back and comment on the sort of forces involved in this crash.
As Emeril would say - Bam! Lets kick it up a notch!
Never too old to have a happy childhood!
This is a modern car hitting a wall at 120mph. This should give you an idea of the forces involved in a crash.
https://www.youtube.com/watch?v=R7dG9UlzeFM
I said, there are accident scenarios that are not controllable with the best crashworthiness measures.
The European standard is one example for a more modern crashworthiness design. The scenarios for the European crashworthiness standard were filtered from 900 accident investigations so that about 80% of these accidents would be covered.
If this accident would fall into these 80% I don't know. At least the shear-back couplers and CEM anticlimber would have helped to avoid overriding I think.
If you think the requirements are not high enough, you can change them.
The Volpe Institute has reserched a lot regarding CEM and done a number of tests and FEM analysis. Their result in a special test series was that passengers are safer in cars designed to European standards compared to American standards.
The Siemens ACS64 was designed for 800,000 lbs buff strength, head-up collisions with other locomotives at max. 25 mph, and a collision with a truck at 68 mph. There are no posts.
www.apta.com/previousmc/rail/previous/2012/papers/Papers/Ward-D-The-New-Siemens-High-Speed-ACS64-Electric-Locomotive.pdf
The FRA approved this concept.Regards, Volker
VOLKER LANDWEHRFor those who are interested the European Standard 15227 crash scenarios on the Voith website:
Leaves you with a hollow ache compared to what happened on 91.
"Scenario 1" -- goes all the way through compression of the crumple zone just to where the 'survival space' (narrow as it is) is left. With collision velocity of 36km/h. That's going to prove much, much slower than the speed of impact in this accident.
Here's the beginning of a report on P42 crashes
I think both locomotives are ac4400CW. They are more than twenty years old. The crashworthiness requirements have gotten higher and alternate crashworthiness designs are possible.
There are accident scenarios that are not controllable with the best crashworthiness measures. On the other hand FRA follows a path that the automobile sector left with the introduction of crumple zones in the early 1960s.
On American freight locomotives pure strength is the still the first goal. Only for passenger locomotives with speeds higher than 125 mph FRA requires Crash Energy Management (CEM) elements. One example for CEM is the Siemens ASC64. In Europe CEM is standard for all modern locomotives. But the crash scenarios in European standard cover only 80% of the crashs.
NTSB has found in a number of accident investigations that the anticlimbers often don't work as intended. That is the reason that locomotive that don't have CEM like the Siemens Charger are equipped with energy absorbing shear-back couplers.
For those who are interested the European Standard 15227 crash scenarios on the Voith website: http://voith.com/corp-en/scharfenberg-energy-absorption/din-en-15227.htmlReagards, Volker
And just three days ago I watched this again:
Crash posts and crumple zones are great and save lives, but above a certain point there's enough energy involved that there isn't a lot that can be done.
I'd say that pending an investigation report on what actually happened, anything is speculation. I'm also pretty sure that by looking at the aftermath that the Amtrak locomotive was airborn and that the bulk of crew safety design is for impact more or less on the ground and from a front or side impact, not the result of a very damaging impact at speed from the front and then falling a number of feet.
Our community is FREE to join. To participate you must either login or register for an account.