Here is some news about this question. Does anybody actually know the answer? Railroad labor advocacy seems to frequently cite this increase of danger with monster trains. However, that view is understandable because everyone agrees that monster trains reduce crew costs, and thus cause a loss of jobs. The media obviously jumped onto that bandwagon in response to the East Palestine wreck, which was then affirmed by the Springfield, OH wreck.
This latest news suggests that engineers may need more training to know how to operate the longer trains.
The feds are warning railroads that their love of long trains is leading to horrible accidents and derailments—but they’re not doing anything about it yet
Well, aside for the serious issue of slack action on super long trains, there is also the mathematical law of averages.
If there is a chance, however small, that a defective car can cause a derailment in a 50-car train, those chances double when you go to 100 cars. Then, they double AGAIN when you go to 200 cars. I think the NS derailment in Springfield, OH, involved a train with 200+ cars.
My hunch is that there must be a way to make long trains operationally safe. We just need to find a way to “push the right buttons” so to speak.
“In 2005, the TSB conducted a safety issues investigation involving an extensive analysis of train derailments and their relationship to bulk tonnage traffic. Loaded high-capacity rail cars in unit trains pose special problems to main lines where weak track conditions (ties, ballast, and subgrade) may be common. A unit train consist is usually uniform; that is, all cars are of the same design and loading, with the car trucks and car bodies responding more or less as one unit. Therefore, each rail car on the train responds to track irregularities in the same manner as the previous car, leading to cumulative impacts at irregularities that the train encounters in the track structure. Trains with numerous rail cars of the same design and with high load capacity provide the track little or no opportunity for elastic recovery during their passage. As a result, high-capacity unit trains can hasten permanent and usually non-uniform track deformation.”
You have quoted the 2020 report accurately, but the 2020 report refers misleadingly to the 2005 study. The 2005 study does not purport to show that the statement is true, it just sets forth the statement itself, without references or support. It is not a conclusion of the 2005 study, it is a hypothesis that is then used to justify the conclusions of that same study, and if that sounds messed up… it gives you a pretty good idea of how well that 200
Short answer? No. The best available evidence I can find is a paper written by my good friend Darwin Schafer back when we were grad-school office mates:
It notes that the traditional model is to divide accident causes into train-mile-related causes and car-mile-related causes, and if you believe in that model then increasing train lengths will always increase the derailment rate per train-mile and decrease the derailment rate per car-mile (i.e. decrease the derailment rate overall). The paper observes in passing that certain categories - notably train-handling - don’t always fit neatly into either category, and warns that you can’t conclude from this study that longer trains reduce derailments over all (especially for trains > 150 cars, which were not well represented in this 2007 study). It’s also worth noting that several “train-mile-related” causes such as passing red signals or exceeding speed restrictions have been reduced in importance by the widespread use of PTC, so theoretically that dimishes the safety advantage of longer trains.
That said - there certainly is not any study out there to suggest that longer trains result in MORE derailments. The labor leaders making this claim are spouting pure BS with nothing to back them up.
FRA thinks that some recent derailments may be due to train makeup procedures, which are kind of indirectly related to train length. But even if that’s the case, there&#
When I asked the question in the thread title, these are the terms and details of that question:
Compare an example of two trains:
TRAIN #1 is 150 cars long with distributed power optimally arranged throughout the train. It has a mixed consist, which is made up of empties and loads, which are distributed throughout the train according to commonly accepted good principles.
TRAIN #2 is 250 cars long with distributed power optimally arranged throughout the train. It has a mixed consist, which is made up of empties and loads which are distributed throughout the train according to commonly accepted good principles. The additional 100 cars of this train are similar in weight and distribution to the cars in TRAIN #1.
Both trains are tested on the same sample of average track with frequent curves and a variety of grades. Ambient conditions are average and identical for both test trains. Operating speeds are identical for both trains. Both trains are operated by the same engineer who is well qualified.
I have had a problem of it just being length of trains. All buff and draft forces are due to how many couplers are on a train. Each coupler allows for some slack. Also any slack action from cushioned cars. Now what about a 15 - 20k IM train made up of 3 and 5 packer well cars.? It might have as few couplers as maybe a 5000 - 8000 regular manifest train.
The physics of train length and handling aren’t part of the actual discussion, any more than actual roller-bearing safety through increased carman inspections is. That we see so much reference to not blocking crossings and keeping more people mandated for various operations… carefully engineered to involve “safety”… gives it away.
Now, mandating a limit in train length between DPU units… that would make sense. So would regulation of train makeup, which so many railroads have demonstrated lethal incompetence in arranging. As you note, long consists of well cars, even baretable, have far less ‘unsafe’ potential than uncoordinated long-travel cushion cars. (One of the fun things advanced ECP makes possible, although lost on the Feinberg contingent, is that individual braking rates can be modulated during an application to control likely intercar and interblock dynamics.)
It would be nice if someone created a graphic computer model that demonstrates the actions of so-called “in-train forces” and how they act in a long freight train as it travels over varying track geometry at varying speeds.
There is a lot of talk that the advent of much longer freight trains comes with the danger of more high speed derailments. They say this is obvious because the longer trains are heavier and thus more likely to derail. But why should that be just a forgone conclusion? Railroad labor advocacy claims this to be a fact as though it should be obvious. Apparently, so does the FRA.
I would conclude that slack is not the primary creator of buff and draft forces. The primary creator is locomotive tractive effort and braking. There would be buff and draft in a train even if it had solid drawbars and no slack at all.
But what slack does allow is the buff and draft forces
It has already been done. I was given a opportunity by one of the Senior Road Foremen of Engines about 30 years ago to operate one of CSX’s Engineer Training Simulators. Simulator could be programmed, on demand, to run any Subdivision on the property and any train that existed on the CSX Car & Train Database could be loaded - with the engine consist that operated that train IRL.
When making throttle and/or brake inputs there was a graphic representation of the various intrain forces that were being generated with the territory being negotiated. At the time, CSX’s maximum train length on most territories was 9000 feet as this was well before the implementation of PSR principles.
Within the last year or so, UP announced a computer program that can run a train’s route and show where problems might happen. I don’t think it is used to reposition cars, just give them an advance heads up about where something might happen.
Just looking at a train list is sometimes enough because it’s obvious that things should be changed. A few times I know where a crew raised objections and were told to go with it. Then the train derailed on that crew’s portion of the run. (Funny how even though the crew told the FRA investigators that fact, it didn’t make it into the FRA accident report.)
DP is not the panacea it’s made out to be. Yes they do help. All our trains over 10000 feet need a mid train DP. Longer trains over a certain weight threshold need a mid and rear DP. Some still get torn up, sometimes into three or four pieces. Sometimes it’s a problem with the DP that causes the initial action that results in a train breaking into two.
Not all trains are the same. One of our mixed manifests is often 60 or 70 % cushioned drawbars. We have a couple that have few of the cushioned drawbars. Both types can often be in the 12000 to 15000 foot range. Guess which type is likely to have problems out on the road.
We’ve had some intermodals up tp 18000 feet. Many are often in the 12000 to 15000 foot range. They normally don’t have many problems. (Other than open container doors.) They are relatively light and don’t have cushioned drawbars. They aren’t bad to run.
Regarding air brake usage, Most trains I get I only have to use air when stopping. Eastbound, except for light trains, like empty unit trains, I will need to use air once for sure to control speed. That’s coming down the short 1.25% grades coming down into the Missouri River valley. There’s two other areas eastbound where I
Generally, ECP brakes have been promoted on the basis that they provide much shorter stopping distance of freight trains. This claim was always quantified by the percentage reduction of stopping distance. However, to the best of my knowledge, this claim was never fully qualified in public promotion. Such qualification would have stipulated that the claim only applied to brake “Service” applications because with brake “Emergency” applications, the stopping time/distance reduction was negligible.
Here is an example of that claim from The Railway Technical Website:
“With the new responsiveness of ECP braking, braking distances will be reduced. A range of 30 - 70% reduction has been quoted. This will allow shorter stopping distances and will, in turn, allow higher speeds.”
This specification makes no mention of the fact that it
On ‘my’ division of CSX, there were a number of TTSI’s that related to train make-up that limited the positions of various cars/types when built into trains. Many of these restrictions were related to the trailing tonnage that could be in the train behind such cars. My division did include mountainous territory with a high degree of curvature in surmounting those grades. These restrictions had been developed from the examination of causes of derailments over the years - learned in ‘blood’. While these restrictions were second nature to the yardmasters on the division who made every effort to comply with the restrictions - my divisions restrictions were not uniformly enacted across the company as a whole. Flatlanders did not have the restrictions, even though they were building trains that would operate through the territory that occasioned the restictions. A company failure in my mind.
“The train consisted of three head-end locomotives and two mid-train DPUs, with one head-end locomotive offline. The train was traveling on an ascending 0.6% grade with the heavier part of the consist (the back end) on a 0.7% downhill grade. The weight was mostly concentrated at the head and rear ends of the train.
During the incident, dynamic braking was applied only to the head-end locomotive consist, while the DPUs were idle, making the train function like a conventional train.
The derailment happened at the sag between ascending and descending grades, with short, empty rail cars designed to ship coiled steel being the first to derail.
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I conclude that ultra-long trains made possible by distributed power, have disproportionably more complex and more violent train dynamics than relatively shorter trains such as less than 100 cars. With the longer trains comes a large variety of random slack force patterns that can be difficult to understand and control. These conditions found in the ultra-long trains cause derailments due mostly to hard slack run-ins.
The core issue is not that locomotive engineers fail to understand what train handling is needed to offset these slack issues. The real problem is that the core issues of long train slack dynamics are not sufficiently understood by the ones who decide to run the ultra-long trains. The most attention to the problem has been focused on train makeup, which has always been recognized as being critical even before the advent of ultra-long trains. But train makeup alone does not seem adequate to solve the greater tendency for derailments that comes with ultra-long trains. Therefore, I don’t think that optimum train makeup will solve the problem. It will help, but it does not go far enough.
So, to the question of whether ultra-long trains cause derailments, I conclude that the answer is YES. There is also a growing movement that concludes likewise. The FRA says the solution is for locomotive engineers to solve the problem by keeping up with the demands of increasing train length practice. That seems like a predictable response. The FRA does not have a solution, but they are sure there is one.&
Here is some news about this question. Does anybody actually know the answer? Railroad labor advocacy seems to frequently cite this increase of danger with monster trains. However, that view is understandable because everyone agrees that monster trains reduce crew costs, and thus cause a loss of jobs. The media obviously jumped onto that bandwagon in response to the East Palestine wreck, which was then affirmed by the Springfield, OH wreck.
This latest news suggests that engineers may need more training to know how to operate the longer trains.
The feds are warning railroads that their love of long trains is leading to horrible accidents and derailments—but they’re not doing anything about it yet
With the current trend of ultra-long trains, I understand that the preferred method of braking is not air brakes, but rather dynamic brakes. Dynamic brakes apply only on the locomotive units. When the units used to be all on the head end, the use of dynamic brakes limited train the length (and was limited by train length) because their application caused all of the trailing tonnage to run in against the locomotive units, whereas air braking restrained that run-in force by applying brakes to all the cars in addition to the locomotive units.
However, with the advent of locomotive units being distributed throughout the train, this distributed power also distributed the dynamic braking. It still had the disadvantage of slack run-in resulting from no braking on the cars, but only on the locomotives. However it did offer the advantage of at least spreading out the dynamic braking even though it left no direct braking on the individual cars.
Distributed power was a new development that eliminated the need to place all the power on the head end. So by spreading out the power in the train, distributed power allowed longer trains without the danger of pulling them in two; a danger that is greatest with all of the power pulling from the head end.
DP also allowed increasing the use of dynamic brakes in lieu of air brakes because DP also spread out the braking force of
Probably be easier to equip them with magnetic or clamp-on battery-powered accelerometers, and store the results with GPS location and timestamp, then stream all the results wirelessly. Assign an IoT address to each one to keep them definitively apart.
Where the effort ought to be placed is better control of the ‘fence’ activity in Locotrol so that any trailing power modulates its dynamic correctly for the part of its train between nodes. Without that, any long train on an irregular profile might indeed be another Springfield cocked and unlocked…
You’d use exactly the same set of accelerometers, feeding into one of the train management programs, to figure out what that ought to be, and what permanent methods should be implemented (probably as an AAR standard) to deal with it.
In the early 1990’s CSX had a Simulator for Engineers that married the calculation of in train forces by using the data of actual trains that had been operated and the ability to operate that train of data over any of the territory CSX was operating.
Of course in the 1990’s Distributed Power was not on CSX’s horizon.
I am certain that in the 21st Century, the CSX Simulator does replicate that various operating modes with DPU in one or more locations within specified trains; with those location(s) able to be manipulated on instructor demand.
In my use of the simulator what was missing was the actual physical impacts from slack action - the buff and draft kicks in the pants.