Sort of like what happened to the Challenger. Dold weather made the O rings hard allowing leakage. Maybe a redesign in the brake cylinders would be called for. I am NO engineer, but too many of these are occuring.
charlie hebdoWhy was the train parked for nearly three hours while waiting for another crew?
Getting recrews to trains that are stopped in remote areas is not the easiest thing to do - especially if it had been considered that the crew that went into emergency was figured to have sufficient time to make their crew change point prior to having their problems.
Don't know the particular realities of this location. In the US all crews get a nominal 2 hour notification before their on duty time. Once on duty they must be transported to the location where the prior crew went HOS. Sometime the conveyance taking the recrew to the HOS site will bring the 'dead' crew back to the terminal, other times two conveyances will be used and the 'dead' crew will be long gone from the scene.
Never too old to have a happy childhood!
charlie hebdo Why was the train parked for nearly three hours while waiting for another crew?
Why was the train parked for nearly three hours while waiting for another crew?
I don't know. I recall some reporting about spending time inspecting the train. The previous crew had stopped by making an emergency application. Does that then require an inspection? I am guessing it would, but I don't know for sure. But aside from the train having been stopped by an emergency application, there was a real emergency in the form of the brakes not holding the train's speed down to where it should have been and was expected to be when descending the hill. That would indicate a very serious problem.
I would think that somebody higher up than the second crew had to make the decision for the train to depart. It seems evident that whatever the problem was that produced the insufficient braking experience by the first crew, it was the same problem that caused the emergency application to leak off as experienced by the second crew.
So that suggests that the inspection never found the problem. If it did not find the problem, how does one conclude that the problem does not still exist and is waiting to do the second crew what it did to the first crew?
How does one assume that the problem is gone just because it can't be found? Yet that is apparently what happened. Or maybe they were still inspecting when the emergency application leaked off and thus were blindsided to the same extent as the second crew.
Maybe the inspection found no problem with the air charging and brake application and release, and concluded that the problem must have just been snow on the brake shoes.
Euclid BaltACD Hand Brakes, Hand Brakes, Hand Brakes! Original crew set the trap that was sprung on the relief crew. No—maintain the brake cylinder packing, maintain the brake cylinder packing, maintain the brake cylinder packing! There was no requirement to set handbrakes. The original crew did not set any trap that was sprung on the relief crew. All they did was save the train and their lives by complying with the requirement to dump the air because their train was running away. The trap that was sprung on the relief crew was the decision to proceed down the grade without knowing what the problem was that caused the train to run away with the original crew.
BaltACD Hand Brakes, Hand Brakes, Hand Brakes! Original crew set the trap that was sprung on the relief crew.
Hand Brakes, Hand Brakes, Hand Brakes! Original crew set the trap that was sprung on the relief crew.
No—maintain the brake cylinder packing, maintain the brake cylinder packing, maintain the brake cylinder packing!
There was no requirement to set handbrakes. The original crew did not set any trap that was sprung on the relief crew. All they did was save the train and their lives by complying with the requirement to dump the air because their train was running away.
The trap that was sprung on the relief crew was the decision to proceed down the grade without knowing what the problem was that caused the train to run away with the original crew.
The trap was NOT SECURING THE TRAIN - to figure out why it was not braking properly! Self preservation trumps rules or the lack therof. Were I your Trainmaster Euclid - you would be on the street for 30 days or fired outright!
In the earlier thread about this wreck, I speculated that the release of the emergency application was due to the pressure leaking off through the brake cylinder piston packing which is a rubber cup. I believe the cold temperature stiffened up that rubber packing cup to the point where the rubber lost its memory and would not return to a tight seal against air pressure.
When these packing cups are new, I am sure they are fully capable of maintaining a seal in the coldest weather encountered. But rubber ages and becomes less resilient. So there must be maintenance instructions that call for replacing these packing cups at specified intervals.
Interestingly while the regulatory body tells us that tests revealed that the car’s air brake system failed to maintain constant pressure over time, they don’t say what components failed in this mission. Surely they know if they conducted extensive testing that revealed that the system was unable to maintain pressure. My bet is on defective brake cylinder piston packing that was not properly maintained.
From the news article:
“After the derailment, investigators took the 12 grain cars that did not derail and conducted extensive tests to the air brake systems, with weather conditions similar to the night of the derailment. The tests revealed that the car’s air brake system failed to maintain constant pressure over time. “The air brake system on these cars would not provide adequate braking effectiveness to ensure the safe operation of a loaded unit grain train in a situation where the air brakes are required to remain applied for an extended duration, such as while descending a steep grade,” TSB officials write.”
FIELD, British Columbia — Hours before a Canadian Pacific train derailed in the rugged mountains of British Columbia, killing three railroaders, the previous crew had struggled to keep the doomed grain train under control on a steep grade. On T...
http://trn.trains.com/news/news-wire/2019/04/19-canadian-investigators-prior-crew-struggled-with-train-involved-in-fatal-wreck
Brian Schmidt, Editor, Classic Trains magazine
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