OTTAWA — Days after Canada’s two Class 1 railroads announced they would appeal a government order requiring the use of handbrakes on trains stopped on mountains grades, one of the county’s largest unions says it’s standing by ...
http://trn.trains.com/news/news-wire/2019/03/15-canadian-union-backs-government-handbrake-rule-under-appeal-by-railroads
Brian Schmidt, Editor, Classic Trains magazine
In piecing together the fragmentary information in the news and comments about the latest CP runaway on Kicking Horse Pass, I conclude the following:
When a CP train is stopped on a mountain grade, the process requires the setting of retainers on many or all cars. Apparently, this is standard procedure on CP and it is lieu of an alternative procedure that calls for setting handbrakes to hold a train during restart rather than setting retainers to accomplish the same thing.
After retainers have been set, the train may be restarted after recharging the reservoirs. Recharging normally causes the train brakes to release, but setting retainers prevents a total release, and is intended to maintain a brake application force adequate to prevent the train from moving until the starting pulling begins.
In the case of this CP runaway, the train had been stopped by an emergency application intentionally made because the train was not properly responding to service applications.
According to normal procedures, retainers were set on a number of cars in the stopped train. The set retainers were expected to prevent the total release of brakes as the engineer fully recharged the reservoirs.
A crew change took place while this train was standing after being stopped by the emergency application. The new crew was onboard the engine pumping air to recharge the reservoirs, and not expecting the train to move because they expected the set retainers to prevent a full release.
However, the train did begin to move as the reservoirs were being recharged, despite the fact that retainers were set and were expected to retain enough of the brake application to prevent the train from beginning to roll.
At this point, the train was rolling downgrade and picking up speed with reservoirs not sufficiently charged to make a new brake application of enough force to slow the train or prevent it from accelerating.
WHY DID THE RETAINERS FAIL TO HOLD ENOUGH APPLICATION TO PREVENT THE TRAIN FROM MOVING?
The force of the emergency application holding the train stopped had reduced over time due to leakage past the brake cylinder piston packing seals on a number of cars. This leakage was caused by extremely cold ambient temperature reducing the sealing ability of the packing seals.
The leakage weakened the grip of the brakes holding the train, but the train remained stationary.
The engineer began pumping air to recharge the reservoirs, which caused the normal release of brakes. However, the retainers were expected to hold a portion of the brake application despite the brake valves on each car calling for a complete release as would be normal during the recharging process.
Because the brake cylinder leakage had already reduced the force of the emergency application that was holding the train, amount of brake force that was retained by the retainers was lower than it would have been if the brake cylinders had not leaked. This resulted in the retained brake application being too low in force to hold the train as had been expected.
The TSB has been quite clear in stating that the train began to move on its own.
The relief Engineer releasing the automatic brake and attempting to recharge the train does not fit with the information provided by the TSB so far.
But I agree that such an attempt in these particular circumstances (mountain grade, extreme cold, no handbrakes set, air brakes most likely leaking off) would have led to a runaway, which of course is what happened.
Greetings from Alberta
-an Articulate Malcontent
SD70Dude The TSB has been quite clear in stating that the train began to move on its own. The relief Engineer releasing the automatic brake and attempting to recharge the train does not fit with the information provided by the TSB so far. But I agree that such an attempt in these particular circumstances (mountain grade, extreme cold, no handbrakes set, air brakes most likely leaking off) would have led to a runaway, which of course is what happened.
I have read that statement by TSB. They said this:
“TSB says train began to move on its own before fatal derailment
Investigators say a Canadian Pacific freight train was parked and began to move on its own before it derailed and killed three crew members on the Alberta-British Columbia boundary early Monday.
'It was not anything the crew did,' safety board investigator says”
I think that what I have described in my post above is not ruled out by the TSB contention that the train began to move on its own.
When I first read that, I assumed that the crew did nothing that could have caused the train to start moving or even set the stage for that to happen. Now, I conclude that the crew was in the process of recharging the reservoirs under the normal belief that retainers would prevent the train from moving since that was the intent of setting the retainers. But there was a failure caused by leakage from the brake cylinders, and that is what caused a condition in which the retainers could not prevent the train from moving during the recharge. So, in that sense, the train began to move on its own. Even if this is what happened, I would agree with the TSB that this runaway was not caused by anything the crew did.
It may also be that the crew had not touched anything relating to the brakes, and suddenly enough air had leaked to allow the train to move. I would not rule that out either.
Ok, I brought up the releasing part. But that was in repsonse to the railroads in question objecting to the TSB's rule on hanbrakes - not about this instance in particular.
My apologies for any confusion.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
We now have a rule that on heavy grade territories hand brakes must be applied when stopped by an emergency brake application from any source.
Jeff
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