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What causes a derailment?

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What causes a derailment?
Posted by Ulrich on Monday, March 9, 2015 3:35 PM

I know there must be a few possible causes, but which one or two account for most derailments? The reason I ask: these oil train derailments seem to be an almost weekly occurrence now. Two weeks ago it was CSX and this week its CN (again). Is it an operational problem (train crew not running the train properly) or is it mostly a track issue or a combination of issues?

 

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Posted by cefinkjr on Monday, March 9, 2015 3:44 PM

As with most things like this, it depends.  In the case of derailments, it depends on who answers the question.

If an operations guy answers, it was clearly a track or equipment failure.  If an MoW guy answers, the crew was running too fast or it was an equipment failure.  And, finally, if an MoE guy answers, the track failed or the crew was running too fast.

And that, friends, is why the 1st three people to arrive at a derailment (after the crew) are representatives of each of those three departments.

Chuck
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Posted by Ulrich on Monday, March 9, 2015 3:50 PM

But politics aside there are probably (in keeping with Pareto's Law) a very few causes that lead to the vast majority of derailments. Maybe 80% of derailments are caused by broken rails. Or maybe 80% of derailments are caused by defective rolling stock components. Or maybe its train handling. I don't know.  

 

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Posted by Euclid on Monday, March 9, 2015 4:26 PM
I am not sure of the distribution of causes, but there are many, many causes.  I don’t believe that one cause stands out as a major problem area.  I am not sure how many derailments get fully resolved as to the finding of cause.  Maybe most of them do.  Maybe somebody can provide a source for the information.  The news always assures us that the cause is under investigation.     
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Posted by Euclid on Monday, March 9, 2015 4:41 PM
 
 
Here are derailment causes that come to mind:

1)    Broken rail

2)    Broken rail joint

3)    Broken wheel

4)    Broken wheel flange

5)    Broken axle

6)    Bearing failure cutting off axle

7)    Broken truck side frame

8)    Broken truck bolster

9)    Broken truck bolster center bearing

10)Picking a switch

11)Picking a crossing frog

12)Getting struck by a highway vehicle

13)Washout of roadbed

14)Collapse of bridge

15)Tornado

16)Softening of roadbed

17)Landslide

18)Rockslide

19)Flash flood

20)Car structural failure

21)Severe slack run-in

22)String-lining from pulling too hard through curve

23)Pulled drawbar dropping on track and derailing train

24)Undesired Emergency Application

25)Dropped brake beam

26)Sun kinks

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Posted by Ulrich on Monday, March 9, 2015 4:47 PM

You forgot meteor strikes, acts of terrorism, rabid bear attacks, and Big Foot.   I know there are many possible causes; however, there are probably only one or two causes that are responsible for 80% of derailments.. After every derailment there's an investigation, what do these investigations show? I would bet that one or two causes dominate over the others.. If they fixed those then the weekly derailments and resulting fire clouds would go away for the most part.   

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Posted by Convicted One on Monday, March 9, 2015 4:54 PM

I would guess that the more frequent "causes" are likely the least spectacular. Such as deviation in the guage allowing a wheel to touch down.

For all the work that gets done maintaining track, I sure see a lot of unusual wear and tear type deterioration.

 I recall recently seeing a molten suplhur train  where the roadbed was so badly beaten up that the track would raise completely off the ground a good foot, in between the wheelsets. The rails would come up with the ties still hanging from them, under  each car as the train passed.  Then I noticed that not ALL ties were coming up with the rail, just most of them. And hitting pretty hard when the rails came down.

 You start missing many ties and maintaining guage would appear challenging.

 

Just my anecdotal observation.

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Posted by nyc#25 on Monday, March 9, 2015 4:55 PM

On my railroad "picking a switch" was not a valid cause to submit on a

derailment report.  It was the result of something else such as a

switch out of alignment or it could be broken switch point.  The bosses

would want to know why the derailment happened at the switch.

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Posted by Ulrich on Monday, March 9, 2015 5:02 PM

Is mishandling of the train ever cited as a cause for derailment? Last night on the news they interviewed a "safety expert" who suggested that railroads need to use their top locomotive engineers on these trains. His comments implied that these oil train derailments are the fault of poor train handling.

 

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Posted by nyc#25 on Monday, March 9, 2015 5:09 PM

Yes,  improper train handling is a valid cause for some derailments.

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Posted by Randy Stahl on Monday, March 9, 2015 5:20 PM

Ulrich

Is mishandling of the train ever cited as a cause for derailment? Last night on the news they interviewed a "safety expert" who suggested that railroads need to use their top locomotive engineers on these trains. His comments implied that these oil train derailments are the fault of poor train handling.

 

 

 

The expert implied... should we assume he has a collection of downloads and evidence to support his assertion ?

I assert that many of these trains are being run with the assistance of the "leader" system and I have not seen one finding laying fault on the engineer (save one).

 

Randy

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Posted by ACY Tom on Monday, March 9, 2015 5:29 PM

One "cause" can be dismissed immediately:  Trains do not JUMP the track, although it's possible for a wheel to be forced over the rail head for a number of possible reasons.

Tom

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Posted by Euclid on Monday, March 9, 2015 5:34 PM

Ulrich

You forgot meteor strikes, acts of terrorism, rabid bear attacks, and Big Foot.   I know there are many possible causes; however, there are probably only one or two causes that are responsible for 80% of derailments.. After every derailment there's an investigation, what do these investigations show? I would bet that one or two causes dominate over the others.. If they fixed those then the weekly derailments and resulting fire clouds would go away for the most part.   

 

You may be right that one or two causes predominate, but I tend to doubt it.  There is a long list of obscure causes that pop up one by one.  They derail trains every day. 

So the list of causes that I provided is not far fetched at all. They happen in rotation day in and day out.

Neverthe less, your question about more widesread, common causes is interesting.  So I look forward to hearing what others think. 

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Posted by Ulrich on Monday, March 9, 2015 5:51 PM

I agree.. not far fetched. Was just funin with you.  But it seems to be a law of nature that a few inputs produce the vast majority of outputs. In the average workplace 20% of the workers produce 80% of the output. 80% of all car accidents are the result of 20% of the driver population etc. 80% of all wealth is concentrated among 20% of the population.  So one might expect that 80% of derailments are caused by 20% of all likely causes. Maybe 80/20 is the wrong ratio, the point is that all possible causes aren't equally likely contributors... there are likely to be one or two or five maybe that are responsible for the vast majority of derailments.

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Posted by Randy Stahl on Monday, March 9, 2015 5:51 PM

Euclid- ice, ice, ice. At least its seasonal..

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Posted by dehusman on Monday, March 9, 2015 7:17 PM

It depends on how fine you want to cut the data.  If you just go track caused, human caused, equipment caused, or environmental caused, yes you can get down to one major cause.  It also depends on what you are considering as derailments.  One wheel down in a yard track or just FRA reportable?  Probably track and human caused are the two biggest.

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Posted by PNWRMNM on Monday, March 9, 2015 7:21 PM

If you really care this is all on the FRA's website.

Mac

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Posted by samfp1943 on Monday, March 9, 2015 7:24 PM

PNWRMNM

If you really care this is all on the FRA's website.

Mac

 

See link @ http://www.fra.dot.gov/Page/P0001

Very 'searchable'

 

 


 

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Posted by CAZEPHYR on Monday, March 9, 2015 7:58 PM

Trains do jump the track.   The PRR had two K4's eastbound on the down hill grade above Horseshoe curve leave the inside track on the and cleared the outside track many years ago due to not controlling the downhill speed.  It never touched the outside track.  

It is rare and involves a lot of speed.

RR

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Posted by edblysard on Monday, March 9, 2015 7:59 PM

The three major causes of derailments are human factor related, and mechanical failure and track defects.

The first consists of things like lining a switch under a car, not properly lining a switch/failing to secure the handle in the latch, attempting to couple cars with mis-aligned drawbars and couplers and excessive coupling speed.

Following those, impropper train movement, like shoving blind, and improper clearance, (cornering cars) exceeding track authority/running a signal.

Failure to secure cars/train, while a big issue in the news, accounts for a small but very "public" amount of derailments caused by roll aways.

Mechanical failure can consist of a whole slew of things from failed bearings, (not that common anymore, current story included) brake rigging failure, also not all that common, wheel defects, everything from cracks to sharp flanges to excessive flat spots and, even more rare, bolster/truck failure.

Last is track defects, stripped joint bars, not an issue on most Class 1s main lines as they are almost all welded rail.

Worn frog points, and broken rail, (several causes from failed subsurface/fatigue) to wide gauge, caused by sun kinks, (expansion) pull aparts, (contraction) failed ties.

If you question concerned the recent "oil train" derailments, I believe you will find almost all of these were caused by track or wheel defects.

MOW forces are streched pretty thin right now, the last summer and winter have both been somewhat extreme.

The commodity itself, crude oil, has been hauled since the early 1900s...the recently raised "sloshing" debate is construct for entertainment...ask any locomotive engineer if sloshing makes a difference in how they handle the train, the answer is no.

In fact, it is the residue cars, cars that have a small amount of product left in them that cause sloshing issues, the baffels in the cars don't slow or stop the residue.

While the media, and the public are concerned with the commodity, the railroads are more concerned with the derailments themselves, which of course should not have happened.

If you are looking for a singular cause, good luck, but in my opinion you already answered the question, it will turn out to be a combination of car defect and or track defect.

 

 

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Posted by ACY Tom on Monday, March 9, 2015 8:24 PM

CAZEPHYR:

I am duly chastened.Embarrassed  I guess excessive rail pounding, plus a curve, could do it.

Tom

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Posted by Ulrich on Monday, March 9, 2015 9:15 PM

PNWRMNM

If you really care this is all on the FRA's website.

Mac

 

 

Only covers US. We seem to have a disproportionately high number here in Canada, maybe due to weather. I don't think the FRA covers Canadian incidents.

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Posted by BaltACD on Monday, March 9, 2015 10:49 PM

Ulrich
PNWRMNM

If you really care this is all on the FRA's website.

Mac

Only covers US. We seem to have a disproportionately high number here in Canada, maybe due to weather. I don't think the FRA covers Canadian incidents.

While Canada may not use the same exact codes - the causes that the codes describe apply equally in the US, Canada and any other railroad in the world.

http://safetydata.fra.dot.gov/officeofsafety/publicsite/downloads/appendixC-TrainaccidentCauseCodes.aspx?State=0

Train Accident Cause codes

1. Track, Roadbed and Structure
2. Signal and Communication
3. Train Operation – Human Factor
4. Mechanical and Electrical Failures
5. Miscellaneous causes not otherwise listed
Train accidents are frequently the culmination of a sequence of events, and a variety of conditions or circumstances that may have contributed to its occurrence and have met the dollar criteria for reporting. Appendix C provides the Train Accident Cause Codes to be entered on FRA, form 6180.54. Refer to FRA Guide for Preparing Accident/Incident Reports, and Chapter 7 for detailed information about Train Accident Cause Codes.

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Posted by oltmannd on Tuesday, March 10, 2015 11:58 AM

Looking a the FRA report for 2010, almost 40% of the cost is track defect related.  About 20% is freight car running gear related (trucks, wheels, axles, bearings) -mostly bearings and wheels.  About 15% of the cost is human factors.

Total cost for train accident damage was $265M in 2010.

(I would think a "smart" freight car could knock the stuffing out of that 20% -but that only buys you ECP for about 1-2% of the fleet.)

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by BaltACD on Tuesday, March 10, 2015 12:11 PM

Since 2010, on my carrier, both the number of 'Defect Detectors' as well as the kinds of defects they are looking for have expanded at great deal.  On my carrier many of the Detectors are also equiped with a Car Identification Scanner and when a defect is encountered it creates a notice to the appropriate operating supervision, in addition to a broadcast of the defect over the road radio channel to the crew of the train.  The occurrence of the defect is also logged in the cars computer history along with it's relative severity (various defects have increasingly severe level - some levels only require monitoring and others requrie immediate action).

In addition to the normal Hot Box, Height & Width and dragging equipment detectors, the new varieties also measure Wheel Impact levels, Unbalanced weight distribution and about 20 other elements of rail car health.  Some defects permit the trains, after on the ground inspection, to continue to a terminal at reduced speed to set the car out; other defects require immediate setout at the nearest location and restricts the train to 10 MPH to that location.

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Posted by Paul_D_North_Jr on Tuesday, March 10, 2015 10:16 PM

Would be interesting to know if any of the WILDs (Wheel Impact Load Detectors) has ever picked up anything in a crude oil train during acceleration or braking that would correspond to a 'sloshing' effect.  I'm thinking not, but it might be an interesting test to run a couple of times. 

A few more thoughts on 'sloshing':

  • No way would sloshing generate enough heat energy to affect the steel of the car.  To do that would require so much horsepower in addition to that needed to haul the car (say, 2 HP/ ton = 250 to 300 HP per car) that it would be noticed by the operating officials and investigated.  It's too late tonight to do the math and post it, but essentially it involves converting HP-Hrs. to BTUs, and then applying the BTUs to the many gallons of crude oil in each car.  (Recall that one of the units of energy - the Joule or BTU, I think - was defined by the amount of energy needed to raise 1 lb. of water by 1 deg. Fahrenheit, using a paddle in a tank of water = sloshing).  
  • A partially-filled tank car slowing down would act a lot like a hydraulic shock absorber - no sudden impact in an instant as with a load of steel beams, but a more gradual build-up and relaxation of force.  The corollary to that is that the analysis and prediction of the train forces - "buff" (push, or compression) and "draft" (pull, or tension) - from that is extremely complex, seemingly almost random without a lot of data oin the cars, grade, speed, etc., etc., and a sophisticated theory and computer program to match.  There's a great quote in a "Letter to the Editor" from a Westinghouse Air Brake Senior Scientist named Norman Vautz about simulating air brakes and train dynamics in response to a David H. Hamley article about air brakes in Trains from the late 1960's (if I'm recalling all this correctly . . . ) that goes something like: "The occasional buckled boxcar reminds us that the agreement between theory and practice is, at times, poor."  Smile, Wink & Grin

- Paul North.

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Posted by Deggesty on Tuesday, March 10, 2015 10:42 PM

Hey, Paul, I've been out of school longer than you have, and I remember that a BTU is a measure of heat, and a Joule is a measure of electricity.Smile

Johnny

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Posted by erikem on Tuesday, March 10, 2015 11:28 PM

They's both units of energy, though the BTU is the amount of heat needed to raise the temperature of 1 pound (mass) of liquid water (presumably 68F) by 1 degree Fahrenheit. The Joule can be defined as 1 Newton-Meter and was the MKS/SI version of the erg (1 dyne-cm). The definition of Volt and Amp were set by having 1 amp of current flowing across a potential difference of 1 volt for one second being equal to a Newton-Meter.

Then again, I've done a lot of work in measuring energy in eV and measuring mass in eV as well...

 - Erik

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Posted by K. P. Harrier on Wednesday, March 11, 2015 12:53 AM

Psychic Forces from Get-Even Railfans?

A certain grade crossing of a first class railroad was revisited.  While there, the thought (“thought”) that THAT grade crossing would be a most interesting place for a derailment to occur at.  A few weeks later a big derailment did happen at that very grade crossing!

Was it some great psychic force of mine that caused it?

Visiting the derailment site, during cleanup operations, one onsite worker that had a supervisor type status briefly conversed with me.  He volunteered that the derailment was caused by wide gauge.

Since I don’t toy with so called psychic forces, standing by the track a few weeks earlier I must have subconsciously sensed the gauge was wider than normal, but couldn’t put my finger on it, and thinking of a derailment was a manifestation of what I couldn’t put my finger on. 

Anyway, to that lengthy list of derailment causes, add wide gauge.

----------------------------------------------------------------------------------------------------------------------------------- K.P.’s absolute “theorem” from early, early childhood that he has seen over and over and over again: Those that CAUSE a problem in the first place will act the most violently if questioned or exposed.

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Posted by BaltACD on Wednesday, March 11, 2015 7:37 AM

K. P. Harrier

Anyway, to that lengthy list of derailment causes, add wide gauge.

Wide guage is not the prime cause - it is a result of a prime cause - most likely something like deteriorated ties that are unable to hold spikes in the proper position and thus allow rail movment - most likely canting away from the track centerline under load.

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