It is not earth shaking news on a national scale, but a loaded eastbound BNSF coal train just derailed in Wayzata, MN. There are lots of buildings right along the track through town. Apparently the wreck missed the buildings, but not by much. According to this report, a torn up rail did penetrate one of the office buildings. The place is a beehive of activity with police blocking several roads and the train strung out through the whole town.
One of the news reporters stated something that I am curious about. The train was 123 cars long with distributed power. The reporter stated that when the derailment began, the engine on the hind end kept shoving, and that is what jackknifed the derailed cars. I would not expect a reporter to come up with that analysis on his own, so I assume that he was told that by someone there from BNSF.
That kind of effect does seem plausible, considering that the first cars to derail were pulled several hundred feet and remained upright and generally in line with the track. But wouldn’t the locomotive on the hind end stopped shoving as soon as the brakes went into emergency?
Wouldn’t the Engineer upon realizing he is on the ground put the train into emergency? At that point the signal would reach the DPU units at the speed of radio waves.
There just isn’t anything you can do about momentum in any case.
Likely the first indication the Engineer had that his train was on the ground was the emergency brake application reaching the head-end. The derailed cars started about 80 cars deep (based on the car numbers visible in the news reports), so the DPU would have gone into emergency before the lead locomotives.
Your explanation makes sense. I would tend to conclude that the momentum jackknifed the cars more so than the DPU locomotive shoving. Although someone else mentioned that the train was only moving 10 mph. The train pulled a few of the derailed cars some hundreds of feet beyond where the other cars jackknifed. I believe at least one of them was standing upright completely separated from the pileup and from the cars ahead of the pileup. A loaded coal car sure does not look like it wants to roll very well on the ballast.
Would the engineer continue pulling with the lead locomotive when the brakes dynamited from the derailment? I have heard of that being done t
The Engineer can release the locomotives brakes but he cannot reapply power until the PCS switch resets, and that won’t happen until the air pressure is restored in the trainline, and the train will be stopped long before that happens. Someone will have to walk the length of the front portion of the train and close the anglecock on the last car still on the rails, before the air pressure can be restored in the trainline.
Apparently, like most of the technologically-challenged media types who ‘report’ on railway mishaps, this individual either flunked or never took high school physics. Even at 10MPH, the tonnage involved has a tremendous amount of potential energy - and jackknifing or even smashing a single derailed car doesn’t dissipate all that much of it. The brakes on cars still on the rails were what got things stopped.
I also liked the whoop-de-do about the brick on the desk in the title company. The outside photo shows that it originated from the window area of the building itself. I’m not denying the fact that the lady was lucky that she wasn’t sitting at her desk when the glass shards came flying in…
The fact that this incident happened in town probably quintupled the amount and intensity of media coverage. If it had occurred out in the woods, or in the middle of Farmer Jones’s pasture, would the local fire and emergency management officials have gotten any TV time? More likely, a one-paragraph quote in the ‘local news’ section of the next day’s paper.
Yes, 10 mph can smash things up, but I really don’t know how fast they were going. They were pulling out of a passing siding and re-entering the mainline. They probably were stopped in the siding, so they may not have been going very fast. But most of time they roll through town there at 30-40 mph. As train wrecks go, this one was rather mild. I have seen much worse.
But I don’t think we have heard the end of the whoop-de-do as you call it. While the collateral damage only involved a few broken bricks, the potential for major collateral damage to buildings in Wayzata is enormous. And this wreck will undoubtedly serve as a real eye-opener for the citizens of the town.
[:-^] [%-)] This a very interesting Thread. The law of physics is apearent, however . The speed of sound is about 634mph. and the speedof electric signal is186k mph. per second.Did both signals go to the DPU??? Or have the " newsies" been throwing darts at a board to see which signal to use. I have a jacknife in my thoughts , needs to be set straight.
Yes, both signals would have been sent, however the DPU would have detected the emergency brake application first and sent the radio signal to the leading locomotives (80 cars from derailed cars to head-end, 43 cars to the DPU). The signal travels in both directions from the point of trainline breakage, so shorter distance to the DPU means that it will detect the application first and then radio the head-end.