Traditionally, even very lightweight equipment, like articulated well sets or 'fuel foiler' skeleton flats, were designed with enough tare weight to be reasonably "safe" anywhere in a consist... a sensible consist, put together by knowledgeable railroad men, and operated by professional and experienced railroad men. That was one of the reasons some of the wackier 'solutions' of the lightweight-trains-of-the-Fifties school of design -- I am thinking specifically of the pre-HSFV four-wheel things like Portager -- often 'failed to thrive' as they were only safe or practical to operate in somewhat restricted service.
We noticed some of the problems with poor blocking of light empties vs. heavies here quite a few years ago; look up any topic or post here with the word 'stringlining' in it, including the famous one that has turned into NDG's thread. Most of the current discussion focuses, instead of stringline derailments of lighter sections trailed by excessive train-factor resistance, on some combination of transverse and vertical buckling from run-in shock. By definition this is a consequence of "poor train handling" -- but that probably unduly shunts the blame onto 'train trash' instead of those who made the train up, and you will note leaves the suboptimal performance of things like Leader and TO "officially guiltless" even when they contribute materially to potential problems like this.
Perry BabinWould it be more likely to cause a stringline derailment (due to the empty cars, let's say 5-10 cars all together) if those empty cars were in the front 1/3 of a heavily loaded train or if they were all behind the heavily loaded cars and any DPUs? I'm sorry if I'm not specific enough, initially, but it's due to ignorance. It's difficult to ask intelligent questions when you know as little as I do about the subject.
I'm sorry if I'm not specific enough, initially, but it's due to ignorance. It's difficult to ask intelligent questions when you know as little as I do about the subject.
The determinants are always grade, curvature, trailing tonnage - how much effort is required at the head end of the string to keep any instant point along the string from the front of the string to the end of the string. Where effort to keep string moving exceeds the efforts of the track/wheel/truck interface to negotiate the grade and curvature.
The values of each wheel/track interface change as each foot of the route is negotiated. The values are different for each rail.
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Perry Babin You wouldn't need to pull hard on empty cars if there weren't any heavy/loaded cars behind them, would you? What am i missing?
You wouldn't need to pull hard on empty cars if there weren't any heavy/loaded cars behind them, would you? What am i missing?
You wouldn't need to, but you might - ever accidentally break your car loose at a stoplight/sign? And, as Balt points out, even empty cars weigh something.
One hundred cars at 30 tons each is 3000 tons. Throw in even a slight grade and a curve and you could have a problem.
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Would it be more likely to cause a stringline derailment (due to the empty cars, let's say 5-10 cars all together) if those empty cars were in the front 1/3 of a heavily loaded train or if they were all behind the heavily loaded cars and any DPUs?
Perry BabinYou wouldn't need to pull hard on empty cars if there weren't any heavy/loaded cars behind them, would you? What am i missing?
Is it one empty behind your 'object car' or 150 empties behind your object car?
ALL cars have weight, loaded and empty.
Back in the day - the day before computers keeping track of the weights of both empties (light weight reported in UMLER) and loads (weight of billed lading added to the UMLER light weight). Yard clerks and Yardmasters would guesstimate the tonnage of trains, nominally 30 tons for a empty and 80 tons for a load.
Perry Babin Shouldn't the light/empty cars be placed at the end of a train to help prevent this type of derailment?
Shouldn't the light/empty cars be placed at the end of a train to help prevent this type of derailment?
A stringline can occur with any consist. They are often low speed events involving very sharp curves, such as you might see in an industrial setting.
Pulling too hard on a string of empty lumber racks on a sharp curve might put just that much too much strain on the cars near the head end, and away they go!
Mention derailment and the general public envisions cars stacked like cordwood, probably aflame to boot.
Because that's what they see on the news...
Most small derailments get no attention. Even the local railfan circles are caught unawares.
Get MOW/mechanical with their chains & blocks, or the cranes if it's a bit more of a mess - clean it up & go back to work. Not a big deal.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
narig01 https://hopeprescott.com/2023/06/02/derailment-at-elm-division-in-downtown-hope/ Several empty lumber cars and a boxcar or two. It looks like they stringlined around a curve. No one was hurt and just a mess, as near as I can tell. I would go look but am currently just out of the hospital. Rgds IGNb
https://hopeprescott.com/2023/06/02/derailment-at-elm-division-in-downtown-hope/
Several empty lumber cars and a boxcar or two. It looks like they stringlined around a curve.
No one was hurt and just a mess, as near as I can tell. I would go look but am currently just out of the hospital.
Rgds IGNb
Not really a big deal. A few years back, a BRC switcher derailed on an industrial lead about a half-mile from my house. Hulcher didn't show up to rerail it until the next day.
narig01https://hopeprescott.com/2023/06/02/derailment-at-elm-division-in-downtown-hope/ Several empty lumber cars and a boxcar or two. It looks like they stringlined around a curve. No one was hurt and just a mess, as near as I can tell. I would go look but am currently just out of the hospital. Rgds IGNb
Without flames or acknowledged loss of life, derailments aren't news.
I should give the location. The curve leading from UP's main north. In Hope, AR at Division and Elm Streets. This is the former Missouri Pacific line from Texarkana to Little Rock.
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