Assigning fault (or blame) to only one party is most likely foolish and unwise. The world is not that simple. It is complex, as in a complex system -- not the same meaning as in "throw up our hands because it is too complex to handle!". Untangling the interrelated factors is complex. Making sense of a complex system honestly is key to finding workable and fair solutions
Imagine that you were a regulator, such as a member of the National Transportation Safety Board [1]. Put yourself in that position. How would you go about deciding the appropriate regulation?
Of course that is not the only stakeholder in the situation. Now for each key stakeholder, including railroad companies, railroad employees, shipping companies, the purchasing public, and landowners near tracks, what would be your professional opinion on the correct outcome?
It is pretty clear that what you see depends on where you sit.
Now step back even further and imagine you are an omniscient being that can truly comprehend all of the above perspectives. How would you go about deciding the correct outcome? It will depend on your notion of good and fairness. I think for many definitions of good, you'll find that considerable analysis is involved.
It feels like you're not commenting in good faith but I'll respond in good faith anyway. As a mechanical engineer, my professional opinion is that trains should not be derailing, period. The trains should be allowed to be as long as possible so that they can safely not derail, and perhaps also not dramatically interrupt traffic in towns. It's hardly a question of "should we ensure that trains do not derail": the answer is unambiguously yes, it is not acceptable for them to derail. I accept that asking "what is the appropriate maximum length for a train" might require some deeper thought, but the article is very clearly stating that the problem is that trains are too long and are derailing, not whatever vague "complexity" you keep going on about.
But it's a matter of probabilities. It's not like a train will derail if it's over some length, and won't derail if it's shorter. A 10-car train can derail, it's just less likely at least for causes that are related to train length.
There is no regulation that will prevent all derailments with 100% effectiveness.
The normal way engineering is done is to create a safety margin so that the probability of a serious problem under normal operation is vanishingly small. Airliners do not fall out of the sky on a regular basis in the United States for that reason. Serious problems have become rare through serious application of serious standards.
Engineering rail systems so that derailments do not happen at all is a reasonable shorthand for almost never. It is engineering malpractice to run things so close to the edge that fatalities or serious property damage are to be expected next month instead of sometime in the next few decades or so.
That's true, but there are also engineering principles at play unrelated to probability. If I squeeze a piece of hard spaghetti on it's ends, would it be easier to break a 20cm piece of spaghetti or a 1cm piece of spaghetti? 20cm, obviously, and that same principle applies with trains. Longer trains are harder to stop, harder to control, less robust to disturbances. Likewise, if I squeeze a piece of soft spaghetti on its ends, it's harder to predict how it will bend if it's really long than if it's really short. You won't see a 1cm piece of spaghetti contort itself into loops, but a 20cm piece certainly will.
The spaghetti metaphor tells part of the story, though I’ve never seen spaghetti somewhat coupled (constrained) to some kind of path (analogous to a track).
> Longer trains are harder to stop, harder to control, less robust to disturbances.
All other things equal, this seems plausible, but I’m no expert on trains. So if I studied it, I would likely agree in most cases.
However, I do wonder if longer trains, being more massive, do offer some benefits in some cases. Perhaps a disturbance affecting only one car would have less effect because the other cars have more inertia and resist change.
This of course relates the question of the design criteria. Clearly trains should be designed with a cost benefit analysis such that more common disturbances can be handled. What kinds of disturbances can and should be planned for?
I respect the mechanical engineering point of view.
> As a mechanical engineer, my professional opinion is that trains should not be derailing, period.
I was also trained as an engineer. Part of that training is understanding probability and risk. There is going to be some risk of derailment. How do you go about deciding the acceptable risk of development? Have you done such a calculation before? What is it based on?
You seem to have one view about what the article is about. It appears to me that your comments are anchored in that one point of view. It also appears that you dismiss other’s comments that don’t align with your view, sometimes even thinking they are in bad faith.
Are you asking what is 'so complex' about public policy, safety, and economics?
Even if this is only about maximum train length, which it isn't, the underlying dynamics, as they are perceived by and affect all the stakeholders, are complex.
