I think we are getting into the weeds with this big basket of variables. Sure we are always surrounded by millions of variables, and they are changing all the time. At any given instant, they combine to form an instant of reality.
So, when approaching a grade crossing a train crew faces millions variables and millions of options for a responding to them. It is a daunting task. I think a little too daunting to be possible; when you consider that a decision has to be made in only a second or two.
It is being said that in order to make that decision, a person would have to know the effect of all those responses to all those variables. Where does that knowledge come from if not from training and rules? You could learn exclusively by experience, but that would mean a person is running trains unqualified until they finally learn the millions of responses to the millions of variables.
So I have to question whether there are really so many variables that are all that pertinent to the choice of action taken by an engineer.
Earlier in this thread Paul North asked people what their response would be for this hypothetical scenario:
I count just seven individual variables as follows:
Long, heavy train.
Flammable and hazardous materials.
Moving at track speed.
Moving downhill grade.
Densely populated town.
Middle of night right after bars close.
Car approaches with driver acting reckless and erratic.
Surely Paul North’s question cannot be answered based on just this limited list of some of the key variables, right? I am told that we need to know all of the millions of variables before such a question can be even be asked, let alone answered.
Murphy Siding schlimm tree68 The fact that other variables have been introduced should be an indication that there are a lot of variables to consider - as you note yourself. So we're up to over 20 factors that affect the decision a crew has to make. I'm sure if we tried, we could come up with more. So, craft your question about how an engineer would react including those 20+ variables and we'll see what we can do for you. Yeah, 20+ variables. Let's see the list, Euclid. It seems like each variable would affect other variables. For example, let's say there were only 5 variables, and the first variable was track grade. The track grade would have a different effect on each of the other 4 variables, like train length, weight distibution, visability, etc. Instead of having a possiblity of 5 different outcomes, you'd have a possibility of 3125 outcomes. (5x5x5x5x5). Now figure that there might be 100 or more variables. You could conceivably have trillions of different outcomes.
schlimm tree68 The fact that other variables have been introduced should be an indication that there are a lot of variables to consider - as you note yourself. So we're up to over 20 factors that affect the decision a crew has to make. I'm sure if we tried, we could come up with more. So, craft your question about how an engineer would react including those 20+ variables and we'll see what we can do for you. Yeah, 20+ variables. Let's see the list, Euclid.
tree68 The fact that other variables have been introduced should be an indication that there are a lot of variables to consider - as you note yourself. So we're up to over 20 factors that affect the decision a crew has to make. I'm sure if we tried, we could come up with more. So, craft your question about how an engineer would react including those 20+ variables and we'll see what we can do for you.
Yeah, 20+ variables. Let's see the list, Euclid.
It seems like each variable would affect other variables. For example, let's say there were only 5 variables, and the first variable was track grade. The track grade would have a different effect on each of the other 4 variables, like train length, weight distibution, visability, etc. Instead of having a possiblity of 5 different outcomes, you'd have a possibility of 3125 outcomes. (5x5x5x5x5). Now figure that there might be 100 or more variables. You could conceivably have trillions of different outcomes.
The number of potential interactions is large, of course, but use of appropriate statistical modeling can reveal best practices. Heck, you do it every day driving your truck in traffic.
C&NW, CA&E, MILW, CGW and IC fan
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Euclid tree68 Yeah, I'll maybe start a new thread about it. It's kind of buried and off topic for this thread.
tree68
Yeah, I'll maybe start a new thread about it. It's kind of buried and off topic for this thread.
Be advised of something else when you do, though: the order in which you address the different considerations is highly significant, and the actions taken for the first few considerations -- whichever ones they are -- will begin to have effects on both the choice and the nature of subsequent ones.
One of the great points of modern "ECP" braking is that it permits careful modulation of actual braking force right up to the practical limit, moment by moment, of what can be achieved in a given situation.
As we have discussed over and over in dispatching and then verberating these equine subjects, if 'emergency' braking worked on a magic anchor that was guaranteed to stop a train in minimum distance with minimal risk of incidental derailment or run-in problems, then putting the train in emergency would be a logical response to an emergent situation (which is where the word 'emergency' originally came from). You have already been advised by some experts in the field of vehicle dynamics (Buslist for one) that if there is a 'general rule' that should be followed in these inadequate-response-time situations, it should be to get as much 'way' as possible off the train before the inevitable happens -- perhaps that means emergency braking, perhaps that means proportional control, perhaps that means differential braking of multiple sections within a given consist. There is certainly not going to be 'one true rule' that an engineman can follow, perhaps not even a reasonable algorithm to determine the right kinds of action to take. Although of course there will be lawyers who will argue either way (depending on where their bread is buttered) that a crew "should" have taken the "common sense" action that coulda woulda shoulda produced a safer outcome.
EuclidYeah, I'll maybe start a new thread about it. It's kind of buried and off topic for this thread.
A new thread won't change the answers much, if at all. As CX500 notes, providing all of the possible factors that might have an effect simply narrows the area of gray.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
20+ variables? Make that 2,000+ variables at a conservative estimate. For example, you should take into consideration the make-up of the train, with the length and weight of each freight car, its commodity and its placement. Is there a DPU, and where is it located in the train, perhaps a second DPU in another location? Now consider the track, such things as profile, curve geometry, cross level, gauge, and relate that to the position of each car. I'm sure the hogheads on this forum can add a multitude more variables relating to how the train they are running is actually behaving.
This just scratches the surface of the variables that will need to be defined. And even if all variables are identified the answer will, at best, lie in a narrower band of gray between black and white.
tree68The fact that other variables have been introduced should be an indication that there are a lot of variables to consider - as you note yourself. So we're up to over 20 factors that affect the decision a crew has to make. I'm sure if we tried, we could come up with more. So, craft your question about how an engineer would react including those 20+ variables and we'll see what we can do for you.
tree68So, craft your question about how an engineer would react including those 20+ variables and we'll see what we can do for you.
Bucky's theme song.
Norm
I expect the subject of this question to be fully addressed with an automatic system working with PTC. Sensors will monitor the approach of vehicles at grade crossings and make the appropriate train brake response as needed. The program will instantly account for the thousands of variables.
When this is implemented, we will finally know whether the variable of train consist and danger of the cargo will be a factor in the automatic decision. Sarah Feinberg says the FRA is looking at everything that can be done to reduce the grade crossing hazard in this country. She seems particularly interested in improving train braking, and has spoken frequently about the derails.
EuclidYou have not been saying the same thing all along. Earlier, you answered Paul North’s hypothetical question about train operation based on only nine variable factors. I can think of at least twelve more variables that Paul either did not include or could be stated more explicitly. Since then, you have also introduced several new variables that need to be accounted for, yet you ignored them when you described your response to Paul North’s scenario. How could you come up with that specific answer so easily when so few variables were accounted for? Your answer seemed pretty black and white back then.
The only thing black and white about any of our answers has been that there is no black and white. The fact that other variables have been introduced should be an indication that there are a lot of variables to consider - as you note yourself. So we're up to over 20 factors that affect the decision a crew has to make. I'm sure if we tried, we could come up with more.
So, craft your question about how an engineer would react including those 20+ variables and we'll see what we can do for you.
tree68 Euclid Overall, it sounds like you are saying there can be no right question unless it weaves through all of the countless variables and establishes a conditional relationship with each one. And then the answer would have to calculate the outcome of all those conditions. I suspect that nobody would ever agree on the answer. They probably would not even agree on the question. Bingo! Give the man a cigar! He finally figured out what we've been trying to tell him all along!
Euclid Overall, it sounds like you are saying there can be no right question unless it weaves through all of the countless variables and establishes a conditional relationship with each one. And then the answer would have to calculate the outcome of all those conditions. I suspect that nobody would ever agree on the answer. They probably would not even agree on the question.
Bingo! Give the man a cigar! He finally figured out what we've been trying to tell him all along!
You have not been saying the same thing all along. Earlier, you answered Paul North’s hypothetical question about train operation based on only nine variable factors. I can think of at least twelve more variables that Paul either did not include or could be stated more explicitly. Since then, you have also introduced several new variables that need to be accounted for, yet you ignored them when you described your response to Paul North’s scenario. How could you come up with that specific answer so easily when so few variables were accounted for? Your answer seemed pretty black and white back then.
Electroliner 1935But we await his response.
Nice one Larry. But we await his response.
EuclidOverall, it sounds like you are saying there can be no right question unless it weaves through all of the countless variables and establishes a conditional relationship with each one. And then the answer would have to calculate the outcome of all those conditions. I suspect that nobody would ever agree on the answer. They probably would not even agree on the question.
Posted by tree68 on Saturday, September 17, 2016 12:56 PM
Your question regarding reaction to an obstruction in a crossing (or elsewhere) needs to include not only the obstruction in the crossing, but the nature of the obstruction, distance to the crossing, visibility of the crossing, upgrade or downgrade, tangent or curve, wet rail or dry, time of year, time of day, speed of the train, makeup of the train (including type of cargo and the placement of loads and empties), traffic conditions at the crossing (ie, T intersections, parallel roads), and the nature of the neighborhood/area.
These are all factors that have an effect on the decision a crew will make when faced with a situation. And I'm sure others can add more.
Change any one of those factors and I'm sure the answers you get will also change.
Hence the "shades of gray."
tree68 Euclid Okay, then what is the right question? Go back and read my entire post. You are insisting on black and white where it does not exist. If you go back and ask your original question, with information on all of the qualifying factors I listed (and more, actually) and you might get something resembling a firm answer. Might. I'm sure that even with all the information I listed, no two crewmembers will provide exactly the same answer.
Euclid Okay, then what is the right question?
Go back and read my entire post.
You are insisting on black and white where it does not exist. If you go back and ask your original question, with information on all of the qualifying factors I listed (and more, actually) and you might get something resembling a firm answer.
Might. I'm sure that even with all the information I listed, no two crewmembers will provide exactly the same answer.
Okay. I had read your entire post. Since you said I might be asking the wrong question, I thought you might know what the right question is.
Overall, it sounds like you are saying there can be no right question unless it weaves through all of the countless variables and establishes a conditional relationship with each one. And then the answer would have to calculate the outcome of all those conditions. I suspect that nobody would ever agree on the answer. They probably would not even agree on the question.
So, there can be no question, if those are the terms. And if there can’t be a question, there can’t be an answer.
tree68I'm sure that even with all the information I listed, no two crewmembers will provide exactly the same answer.
Or one that fits in with Bucky's preconceived notions.
EuclidOkay, then what is the right question?
selector This is circuitous. Question. Wrong question. What's right question? Whatever you want. Just listen to response. I expect a question next....
This is circuitous. Question. Wrong question. What's right question? Whatever you want. Just listen to response. I expect a question next....
Murphy SidingAnything you want it to be. Then provide your own anwser and I presume you'll be happy with the results.
And be willing to accept the answer you get from someone who works in the area of concern.
Euclid tree68 If you feel we're not giving you an answer to your question, then perhaps you are not asking the right question! Okay, then what is the right question?
tree68 If you feel we're not giving you an answer to your question, then perhaps you are not asking the right question!
If you feel we're not giving you an answer to your question, then perhaps you are not asking the right question!
Okay, then what is the right question?
Norm48327If I may take the liberty to add to that, a line from a Simon and Garfunkel song sums it up well.
If I may take the liberty to add to that, a line from a different song sums it up better:
https://www.youtube.com/watch?v=1_47KVJV8DU
ChuckCobleigh Deggesty As a bystander, my observation is that another horse has been flayed. A somewhat lifeless one, at that.
Deggesty As a bystander, my observation is that another horse has been flayed.
As a bystander, my observation is that another horse has been flayed.
A somewhat lifeless one, at that.
Johnny
schlimmI seriously doubt that he is capable of that degree of insight or awareness. His inability to understand simple, declarative sentences makes it obvious that a dialogue is nearly impossible. I suggest the rest of us just leave him to his internal arguments.
If I may take the liberty to add to that, a line from a Simon and Garfunkle song sums it up well. "The man hears what he wants to hear and he disregards the rest."
Horse's lives matter.
Duckin' and runnin'.
BaltACD zugmann Euclid Heh. That's a good one. Tell me another. Never had to deal with the application of rules to the real world, has he?
zugmann Euclid Heh. That's a good one. Tell me another.
Euclid
Heh. That's a good one. Tell me another.
Never had to deal with the application of rules to the real world, has he?
Rules seem black and white until people become involved, and then the interpretation begins. Different people will give you different interpretations of the same rule, making this a damned-if-you-do, damned-if-you-don't world for us on the ground.
And boy was this thread worth the 45 minutes it took to read! Amazing what happens when I disappear for a week.
Greetings from Alberta
-an Articulate Malcontent
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