New Tank Car Regulations Looming

[tree68]

Euclid

I would like to see a proposal for a coupler that is less like a can opener as the above linked article of the Popular Mechanics article mentioned.

I have yet to cut my self on a coupler.  Even an open coupler is more like a battering ram than a can opener, as I see it.  Any object struck by a moving, loaded tank car will act as a can opener - bridge abutments, bridges, the frames of cars, even old rail used as a parking barrier in a parking lot.

A push back coupler will only help if it is pushed along the design axis.  If the coupler connection is broken by vertical or horizontal shearing forces, the push back coupler won't push back, unless there is some form of automatic retraction mechanism.

And that is where the can opener analogy can come into play - if the breaking of the coupler leaves raw, sharp edges.  But if that happens, there are other forces in play that have just as much ability to breach the container as the coupler.

[Euclid]

When I look at the tank car crash testing, there is one aspect of it that seems to be lacking or perhaps even misguided.  However, it would also seem that this simply can’t be.  With the amount of money and talent being thrown at this research, how can there possibly be something obvious that they have overlooked?  I must be missing something in my interpretation.

What I have noticed is that the testing seems to follow the reasoning and methods applied to the long-running automotive crash testing tradition.  That is, where individual vehicles are robotically crashed into each other or into fixed obstacles.  This certainly replicates the conditions of highway crashes.

Following this same model, the tank car tests that I have seen use a single weighted railcar to impact a stationary tank car tank backed up with a solid obstruction.  It appears that the single weighted railcar approximates the weight and speed of a single loaded tank car moving about the maximum speed of an oil train. 

While this could replicate one crash element of a high speed derailment, what about the likelihood of a whole string of tank cars striking one fixed tank car at track speed?  How can the conclusions of tank resistance to puncture be made on the basis of just one car when a wreck can easily apply the collective force of say ten tank cars?  Can they possibly be overlooking this because the thinking of the test is so strongly influenced by automotive crash testing where single vehicle collisions are studied?

 

This photo of the MM&A wreck shows the effect that I am referring to. 

http://news.ca.msn.com/canada/railway-suspends-employee-over-lac-megantic-disaster

 

The train was moving from right to left in the picture.  You can see how the first cars to derail at the left are accordioned, but the pile becomes more tightly compacted toward the right side of the photo.  Toward the right, the cumulative resistance of the heaped cars is greater because there are more of them in opposition to the oncoming cars still on the rails behind the pileup.  All but one of those trailing cars were uncoupled and pulled back to safety by the MM&A engineer while the wreck was burning.  Generally, I understood that he may have pulled as many as ten cars back. 

In the pileup, you can see the effect of the crushing force that was provided by kinetic energy of those ten cars.  Moving to the left from than first car on the right side, notice the two cars side by side, in line with the track.  You can see how the force of the trailing cars shoved those two cars into the car perpendicular to them, ahead of them.  The whole mass of cars in that area toward the right side has the cars crosswise to the track and tightly compacted by the force of the trailing cars.  That force came from no more than ten cars that stopped before then entered the pileup.  Think how much force there would have been if there were say 60 cars feeding their kinetic energy into the accordion heap, which could be the case with an oil train. 

 

Here is a link to an article on tank car crash testing.  On page 6, they show a simulated model of a derailment with cars strewn about.  In that model, I see no indication of the derailed car resistance and force of the cars behind the derailment that would tightly compact the derailed cars and crush them:    

http://ict.uiuc.edu/railroad/images/NewsPhotos/2013/Barkan%20et%20al%202013%20TR%20News%20286%20Cooperative%20Tank%20Car%20Sefty%20Research.pdf

 

[dehusman]

Euclid

Here is a link to an article on tank car crash testing.  On page 6, they show a simulated model of a derailment with cars strewn about.  In that model, I see no indication of the derailed car resistance and force of the cars behind the derailment that would tightly compact the derailed cars and crush them:    

http://ict.uiuc.edu/railroad/images/NewsPhotos/2013/Barkan%20et%20al%202013%20TR%20News%20286%20Cooperative%20Tank%20Car%20Sefty%20Research.pdf

So you can see the formulas they use just by looking at one picture of derailment sequence?

I don't understand what the problem is, the scatter on the simulation is pretty similar to many actual derailments I've seen.  I've seen simulations of actual derailments and they are eerily accurate when compared to the actual derailment.  In one high speed derailment the simulation even had the divots in the ground in the right place when the engine flipped end for end.

These simulations measure the forces in the entire train.

[chutton01]

New Regulations for transport of crude have been released by the FRA:

New DOT Regulations:

WASHINGTON – Today, the U.S. Department of Transportation (DOT) issued an Emergency Order requiring all railroads operating trains containing large amounts of Bakken crude oil to notify State Emergency Response Commissions (SERCs) about the operation of these trains through their states.

Additionally, DOT’s Federal Railroad Administration (FRA) and Pipeline and Hazardous Materials Safety Administration (PHMSA) issued a Safety Advisory strongly urging those shipping or offering Bakken crude oil to use tank car designs with the highest level of integrity available in their fleets.  In addition, PHMSA and FRA advise offerors and carriers to the extent possible to avoid the use of older legacy DOT Specification 111 or CTC 111 tank cars for the shipment of Bakken crude oil.

[edblysard]

Well,

There’s the smoke, the mirrors come later…..

[dehusman]

Wrong, all mirrors, its a non-smoking environment.  8-)

Here is the full DOT press release:

http://www.fra.dot.gov/eLib/details/L05223

And the actual emergency order:

http://www.phmsa.dot.gov/pv_obj_cache/pv_obj_id_D9E224C13963CAF0AE4F15A8B3C4465BAEAF0100/filename/Final_EO_on_Transport_of_Bakken_Crude_Oi_05_07_2014.pdf

[Euclid]

dehusman

Euclid

On page 6, they show a simulated model of a derailment with cars strewn about.  In that model, I see no indication of the derailed car resistance and force of the cars behind the derailment that would tightly compact the derailed cars and crush them...    

So you can see the formulas they use just by looking at one picture of derailment sequence?  I don't understand what the problem is,...

I have no idea what formulas they are using, or whether anything is wrong with the simulation.  I only mentioned it incidentally in relation to the broader point that I was making.  And that point is just an observation leading to a question which is as follows:

Their testing concerns the ability of a tank car vessel to resist puncture by projections extending from other tank cars which collide with resisting tank car.  The resisting tank car puncture depends on the following:  

1)      The strength of the resisting tank car vessel.

2)      The area of the face of the colliding projection.

3)      The force applied to the colliding projection. 

 

Their test controls all three variables and looks for the ability to puncture under those three conditions.

Condition #1 is the variable to be tested in order to learn how strong tank car vessels need to be in order to survive crashes without rupturing.

Condition #2 is based on an assumption of the average likely projection represented by features of tank cars, such as couplers. 

Condition #3 is the representation of one loaded tank car weighing 140 tons and traveling at some given speed approximating track speed of an oil train. 

 

Suppose the test shows that a tank shell made of ¾-inch-thick steel will resist puncturing. 

My question is this:  How can the test result be meaningful when an actual derailment can have a widely varying number of tank cars composing the colliding element?  If the test shows that ¾-inch-thick steel survives impact from one tank car, it will probably not survive impact from two tank cars coupled together.  Yet, a derailment can produce colliding impact from any number of cars from one to fifty or more.   

Their test suggest to me that they view the problem as being the result of just one tank car running into another one, as though all the cars in the train were merely independent vehicles like traffic on a highway.  Their computer model of a derailment with cars loosely scattered about suggests the same thing. 

[dehusman]

Euclid

Suppose the test shows that a tank shell made of ¾-inch-thick steel will resist puncturing. 

My question is this:  How can the test result be meaningful when an actual derailment can have a widely varying number of tank cars composing the colliding element?  If the test shows that ¾-inch-thick steel survives impact from one tank car, it will probably not survive impact from two tank cars coupled together.  Yet, a derailment can produce colliding impact from any number of cars from one to fifty or more. 

Because steel doesn't care how many tank cars are coupled to the projection.  What they are measuring is the force required to puncture a steel vessel.  Using the simulator they could determine what the drawbar forces are in the train and then create a test environment that creates those forces.  They design a car to resist those forces.

There is no need to physically ram X number of cars into the test tank, you just have to get the equivalent forces.

Their computer model of a derailment with cars loosely scattered about suggests the same thing. 

You are making a whole ot of assumptions (once again),

1,  You are assuming that is the final positions of the cars.  You need to read the caption of the picture :

FIGURE 4 Computer simulation models of the dynamics of train derailment were

developed to understand the force of impacts on different parts of tank cars in

accidents: (a) 36-car train model and (b) calculated response of train 25 seconds

after derailment .

That is the position of the cars 25 sec after the derailment.  It is not necessarily the final positition.  We don't know the final position because it doesn't say how long the cars took to come to rest.  If it took 45 sec for the cars to come to rest then the cars would continue to move for an additional 20 sec.

2.  You are assuming all derailments accordian the cars like Lac Megantic.  That's just wrong.  It all depends on the speed of the train, the alignment of the track, how fast the initial cars stopped, where in the train the derailed cars are and the weight of the train.

3.  You are assuming that because of the picture they didn't take the rest of the train into account.  If you read the caption they describe that it is a 36 car train of mixed equipment, they even show the entire train in the picture above.  I have a hard time understanding how you think they would only be measuring the derailed cars because how would they know which cars derailed?  They would only know which cars derailed if they analyzed the entire train.

4.  Based on your assumptions in #1, 2 and 3, you are assuming that the "loosely scattered" pattern of the derailed cars is somehow flawed.  Its not.  It is not atypical.  The scatter pattern varies greatly.  Sometimes there is a pile, sometimes they accordian, sometimes squirt out in all directions.   Depends on a lot of factors.

[Euclid]

dehusman

Because steel doesn't care how many tank cars are coupled to the projection.  What they are measuring is the force required to puncture a steel vessel.  Using the simulator they could determine what the drawbar forces are in the train and then create a test environment that creates those forces.  They design a car to resist those forces.

There is no need to physically ram X number of cars into the test tank, you just have to get the equivalent forces.

You are making a whole ot of assumptions (once again),

Dave,

You say the steel doesn’t care how many tank cars are coupled to the projection.  But if they are measuring the force required to puncture the steel, as you say, the steel most definitely does care how much force is applied.  Isn’t that the whole point of the test?  And since the force applied rises with the number of tank cars that are coupled to the projection, how do you conclude that the steel does not care about the number of tank cars?

Perhaps you are saying that their test amounts to a scaled down version of the actual forces applied, and then they will simulate the actual strength needed to resist the actual forces based on the results of their scaled down test.  But if they can simulate the results, why even test with actual destruction of full size models? 

In our previous discussions, you have downplayed my idea that great cumulative forces can be applied to tank cars due to impacts from multiple cars coupled together.  I believe your point there was that a tank car receiving such impact will simply be displaced out of the line of force and escape relatively uninjured.  So when I wondered why they were using just one car in their test, the use of just one car would support your contention that the effect of multiple cars does not matter.  Could that be the reason why they only use one car in the test?  If so, that would be the answer to my original question above.

I did read the caption for the illustration of the derailment simulation and did notice that it referred to the scatter effect as being 25 seconds after the derailment began.  I should not have assumed that the derailment had stopped by this point and that the scatter pattern was the final result.  It may have continued for some time, and ultimately resulted in a more compacted pattern as I would generally expect.  In any case, my point in referencing that illustration is only remotely incidental and speculative to my larger point.  I drew no conclusions from it.   

You also said that I had made several other assumptions that are wrong.  Actually, I did not make any of those assumptions that you say I made.  You are misinterpreting me, inserting your own meaning for what I said, and then disagreeing with that meaning. 

To be specific, I cited the Lac Megantic accordion pileup as an example of a force pattern that is very common in derailments.  I did not state or assume that every derailment happens in an accordion pattern like Lac Megantic, as you say I did.  I realize that derailments can produce an infinite variety of patterns. 

I did not state or assume that the picture of the simulated derailment in the illustration only included the cars that are shown, or that they only analyzed the forces of those cars and ignored the forces in the rest of the train, as you say I did.

I did not state or assume that the pattern of derailed cars in the simulated derailment is somehow flawed, as you say I did.