oltmannd Bucyrusrequires that enough brakes be set to prevent the train from rolling, but they don't say how that is to be determined. How do you know if you've applied the parking brake in your car with enough force to keep the car from rolling? What test do you perform to check? I'll answer that...you see if the car rolls after you set it. Why wouldn't the same rule apply to a train? The engineer knows he has enough handbrakes set because the train doesn't move!
Bucyrusrequires that enough brakes be set to prevent the train from rolling, but they don't say how that is to be determined.
How do you know if you've applied the parking brake in your car with enough force to keep the car from rolling? What test do you perform to check?
I'll answer that...you see if the car rolls after you set it.
Why wouldn't the same rule apply to a train? The engineer knows he has enough handbrakes set because the train doesn't move!
Don,
I understand that, but the question that I am asking is about refers to Canadian practice.
Transportation Safety Board of Canada has stated publicly that the push-pull test is unreliable. Since Rule 112 does not say specifically to use the push-pull test, and because the TSB says that the push-pull test is unreliable; it raises the question of how to comply with rule 112 if the push-pull test is unreliable.
jeffhergertWe just release the automatic and independent brakes after tying the hand brakes. Once the cars start to release, you know quite soon if the train is going to move or not.
Jeff,
When you release the air and find you have enough handbrakes to hold the train, do you just leave it at that, or do you then set a specific prescribed number of additional handbrakes as a final safety factor?
BaltACD oltmannd Zoom! You car rolls away down the hill, crashing into the elementary school at the bottom of the hill, wiping out a kindergarten class. You have a choice to park your car on a hill or on the flat - even though it would cost you a few hundred steps. Which would be safer? And the School Board had a choice and built the school where gravity endangers it. You build the school on the high ground! Duh!
oltmannd Zoom! You car rolls away down the hill, crashing into the elementary school at the bottom of the hill, wiping out a kindergarten class. You have a choice to park your car on a hill or on the flat - even though it would cost you a few hundred steps. Which would be safer?
Zoom! You car rolls away down the hill, crashing into the elementary school at the bottom of the hill, wiping out a kindergarten class.
You have a choice to park your car on a hill or on the flat - even though it would cost you a few hundred steps. Which would be safer?
And the School Board had a choice and built the school where gravity endangers it. You build the school on the high ground! Duh!
Yup. But they didn't ask me where to build the school. I only get to decide where to park my car.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Bucyrus oltmannd Bucyrusrequires that enough brakes be set to prevent the train from rolling, but they don't say how that is to be determined. How do you know if you've applied the parking brake in your car with enough force to keep the car from rolling? What test do you perform to check? I'll answer that...you see if the car rolls after you set it. Why wouldn't the same rule apply to a train? The engineer knows he has enough handbrakes set because the train doesn't move! Don, I understand that, but the question that I am asking is about refers to Canadian practice. Transportation Safety Board of Canada has stated publicly that the push-pull test is unreliable. Since Rule 112 does not say specifically to use the push-pull test, and because the TSB says that the push-pull test is unreliable; it raises the question of how to comply with rule 112 if the push-pull test is unreliable.
You follow your railroad's interpretation of the rule which likely is like NS's. Release the independent and automatic and see if the train moves. Just like when you set the parking brake on your car.
oltmanndYou follow your railroad's interpretation of the rule which likely is like NS's. Release the independent and automatic and see if the train moves. Just like when you set the parking brake on your car.
It is obvious that setting handbrakes to hold a train on a grade is as much art as it is science. There are too many variables to make it entirely scientific. Brake winches can lack proper lubrication to the point where they require more torque to set to the same brake pressure as a well lubricated brake winch. So a person setting brakes cannot know how effective the brake will be. That variable makes the minimum guideline rather meaningless.
While this mixture of art, science, good judgment, good luck, and guesswork has been common practice, it is not sufficient in situations where a runaway train will be disastrous to population centers. In wide open spaces, some runaways will not even derail, and if they do, it is possible that no injuries will result. But in the case of this Lac-Megantic runaway, the parking oil trains uphill from a 10 mph curve through town amounts to holding a loaded gun to the heads of the residents. It should not have been hard to see that before the disaster occurred.
Based on the Lac-Megantic experience, the Canadian Transportation Safety Board has already ordered that oil trains must not be left unattended on a main track.
They have also ordered the revision of Rule 112 in a way that obsoletes the old art/science push-pull method of achieving holding force for trains parked on grades. It sounds like they are going to replace the push-pull test with a detailed specification for setting handbrakes. They will take the guesswork out of it by stipulating the number of brakes, the torque setting, the grade, the tonnage, type of cars, weather, wind, safety factor, etc.
The Canadian Transportation Safety Board says that rule 112 is not specific enough because it does not spell out how many handbrakes to apply for various weights and types of cargo. It also says that the standard, so-called "push-pull test" does not always accurately show whether the brakes have been adequately applied.
Bucyrus jeffhergertWe just release the automatic and independent brakes after tying the hand brakes. Once the cars start to release, you know quite soon if the train is going to move or not. Jeff, When you release the air and find you have enough handbrakes to hold the train, do you just leave it at that, or do you then set a specific prescribed number of additional handbrakes as a final safety factor?
After you set the parking brake on your car to you then go back and give it a few more clicks as a final safety factor?
oltmannd BaltACD oltmannd Zoom! You car rolls away down the hill, crashing into the elementary school at the bottom of the hill, wiping out a kindergarten class. You have a choice to park your car on a hill or on the flat - even though it would cost you a few hundred steps. Which would be safer? And the School Board had a choice and built the school where gravity endangers it. You build the school on the high ground! Duh! Yup. But they didn't ask me where to build the school. I only get to decide where to park my car.
Have fun walking the several hundered feet up the hill! And then comes the earthquake and the hill being accumulated glacier debris creates a landslide covering the school in 100 feet of debris.
The biggest cause of death is conception. From the moment of conception onward, life is a risk and can end at any instant - your fault, their fault, everybodys fault, nobodys fault - the final end result of conception is death - nobody escapes.
Never too old to have a happy childhood!
I have never tied a train down on a grade, so I have never encountered a need to know exactly how many to set. But the context of my question was to ask how it is done without the push-pull test, which the TSB says is unreliable.
Here is an article that gets into a lot of second guessing about handbrake practice in the wake of the oil train runaway:
http://www.thestar.com/news/canada/2013/07/12/lac_megantic_explosion_standards_vary_for_number_of_hand_brakes_required_in_canada.html
Some points from the link:
But that investigation will, as is the case with all runaway trains, home in on the braking systems — particularly the hand brakes. There has been an average of 12 runaway trains a year over the last decade in Canada, according to TSB data.
Federal rules require a “sufficient number” of hand brakes to prevent trains from moving, should all else fail. But what is considered adequate varies widely by company and by crew and, historically, has been far from fail-safe.
In the 2011 Quebec runaway, safety investigators said 57 hand brakes were needed and only 35 were applied. The minimum required, however, was just 12.
Transport Canada’s railroad operating rules set standards, such as “a sufficient number” of hand brakes. It stipulates that crews must test to make sure the hand brakes will hold. Beyond that, railroads operate under their own subset of rules, approved by Transport Canada, that should specify how many hand brakes are required in different circumstances.
Those company-specific rules are not public.
Railway experts vary widely on what they would consider an appropriate number of handbrakes for the train parked in Nantes, on a downhill grade of 1.2 per cent, suggesting anywhere from eight to 30. The British Columbia Safety Authority railroad manual suggests nine handbrakes for 70-79 cars, with extra if the train is on a slope.
Later, he [Burkhardt] said Harding had likely not set the appropriate number of hand brakes for the train, a number Burkhardt identified as 11. The number required would be contained in MMA’s special instructions.
The number Burkhardt refers to might be in the special instructions, but we all agree that there is no “magic number.” A number in the special instructions can only be a minimum or a recommendation. How does Burhardt know that 11 handbrakes was the appropriate number? We all agree that he can’t know the appropriate number unless he does a push-pull test.
Bucyrus oltmanndYou follow your railroad's interpretation of the rule which likely is like NS's. Release the independent and automatic and see if the train moves. Just like when you set the parking brake on your car.Why does the Canadian TSB say that is unreliable?
BTW, there is no such thing as reliable or unreliable. At the end of the day, all things will fail sometime. The only question is to what extent. Even vital relays in signalling fail and cause false clears from time to time.
oltmanndBucyrusWhy does the Canadian TSB say that is unreliable? Because the test can't be done with any measure of reliability or repeatability. BTW, there is no such thing as reliable or unreliable. At the end of the day, all things will fail sometime. The only question is to what extent. Even vital relays in signalling fail and cause false clears from time to time.
BucyrusWhy does the Canadian TSB say that is unreliable?
If the rule requires a crew to set enough handbrakes to hold the train, and if they tested, but still fail to set enough, would the rule infraction be forgiven on the basis that the test they performed was unreliable and failed to give the correct information?
Bucyrus If the rule requires a crew to set enough handbrakes to hold the train, and if they tested, but still fail to set enough, would the rule infraction be forgiven on the basis that the test they performed was unreliable and failed to give the correct information?
If you were driving and had your car well under control to stop for traffic ahead and your foot sliped off the brake pedal and you hit the car in front of you. Would you be charged ?
The final result is the proof - pro or con.
Maybe because it's the simplest explanation. Since the procedure was followed and it moved anyway, the test must be flawed or unreliable.
To answer (although others have pretty much done that) whether we tie more hand brakes after the release test. No. Once everything is stopped, and stays stopped, you've secured the train. That's the whole point of the test. To make sure there is no movement, of if some slight adjustment due to slack, etc, it comes to a stop and stays stopped. If you keep second guessing yourself after the test, pretty soon you'll have all the hand brakes applied, but still won't be able to leave the train unattended. Because nothing will ever be good enough.
To be honest, I don't see how once everything is properly tied down, all (slack, sloshing liquids, etc) motion stopped, the train would start moving again. Unless it had "help" in some form. I wonder if maybe a push/pull test, instead of just releasing the air/independent, could disrupt slack conditions or liquefied loads to cause enough motion to throw off a train's equilibrium where there may be a slight change in track gradient? Enough that the slight motion could push it over the edge. I wouldn't think any grade change would be so abrupt that it wouldn't be noticeable, but I know in some of our yards there's enough change between two adjacent tracks to require different minimum numbers of hand brakes. Yet the tracks look to lay exactly alike.
Jeff
One thing I will identify about railroad discipline - while the Conductor may be the individual responsible for applying the hand brakes to secure a train - if it rolls away - both the Engineer and Conductor will be charged and have discipline assessed against them. Operational failures are viewed as a team effort by ALL members of the crew. The team performs their duties properly or the team pays the price.
In the Spanish overspeed incident - if that were to occur in the US, the Conductor (from a crew discipline standpoint) would be charged in addition to the Engineer - the Conductor has available access to the Emergency Braking system and knows or should have known that the train was operating at a much higher speed than it should have been on the territory when the incident happened. In such cases it is the Conductors responsibility to use the Emergency Brake.
jeffhergert Bucyrus Why does the Canadian TSB say that is unreliable? Maybe because it's the simplest explanation. Since the procedure was followed and it moved anyway, the test must be flawed or unreliable.
Bucyrus Why does the Canadian TSB say that is unreliable?
Why does the Canadian TSB say that is unreliable?
Thanks for that clarification about adding a safety factor.
Regarding the statement by the TSB of Canada, when you say that “maybe because it’s the simplest explanation,” do you mean explanation of the Lac-Megantic runaway? Actually the TSB made their statement in 2009, so it is not a response to the Lac-Megantic wreck. In 2009, they said this:
“Because it is impossible to verify hand-brake effectiveness by pulling or pushing cars on high grades, locomotive engineers cannot accurately know that management's expectations have been met every time cars are secured in accordance with CROR Rule 112.”
The news indicates the Lac-Megantic runaway has rocked the consciousness of railroad safety in Canada, and the response might spread to all of North America. As many here have said, my question about the number of handbrakes is unanswerable. The number can only be found empirically, by a practical test to see if enough brakes have been applied tight enough to prevent the train from rolling. In Canada, the Transportation Safety Board of Canada has said in 2009 that the empirical test is unreliable on mountain grades.
In Canada, questions are swirling around this very issue of how to secure trains by handbrakes and know that it is safe. There has been a lot of news focusing on the recommended minimum number of handbrakes to set, and how that number varies widely from one railroad to another, and the fact that there are conflicting numbers on a single railroad. There is news about the rule calling for the empirical test to make sure enough handbrakes are set. There is news that asks how the empirical test can be safe without a safety factor, as Paul North had mentioned along with other excellent points in the last post on page 5 of this thread.
There is also some attention on the fact that railroads individually interpret these rules and recommendations according to their preferences, and are not required to make that information public. So they choose not to make it public. Therefore, in light of the MM&A disaster, there are a lot of questions about securing trains and not enough answers.
Whatever conclusion can be drawn from all this probing, it is clear that the empirical test is essential to the safe handbrake securement of a train on a grade. And yet, the preeminent railroad safety authority in Canada says that the empirical test is unreliable. They said this in 2009:
This is amazing. If the empirical test is unreliable, you don’t have a safe and reliable means to secure trains with handbrakes. That seems like an astounding revelation in the wake of the worst train runaway in Canadian history. The public asks how they can know that unattended trains are safe, and the answer is that they cannot know.
The public can’t know that trains parked on grades are secure until the Transportation Safety Board of Canada comes up with an effective alternative to the empirical test. I have not seen much beyond just a hint of what that alternative might be. It would be interesting to learn what their plan is, but right now, they won’t speak to the public about these train brake issues.
I can’t imagine that they are too comfortable about having announced that the empirical test was unreliable in 2009, and had four years to do something about it before the Lac-Megantic disaster. It appears as though the very core of the cause of that disaster goes right to the unreliable empirical test which was apparently omitted for some unknown reason.
Of course, there has been nothing said about a person or persons, unknown, or some other event/circumstance that interfered with the brakes that were set and the number the engineer had set was totally adequate if the external interference had not occurred.
I can think of at least one scenario where one of the firemen might have deliberately released the brakes on all the cars so as to prepare to get them moved out of the way, in case the engine fire spread.
Then there is the unknown person that came by and did so maliciously.
I hope they investigate enough to know for sure they are not just making the Engineer the "goat".
Semper Vaporo
Pkgs.
One reason the "push-pull" test is unreliable is because of something I've seen numerous times. The hand brakes are holding the train/car just fine - often for extended periods with no air to help them out - yet when the car is moved (secondary to coupling or otherwise bumped), it will continue to roll.
Our procedure (specifically on grades greater than .5%) is to set hand brakes, release all air, and see if they hold. No power is applied. If they hold, we're good. If not, keep adding brakes until they do (or make sure the brakes already set are fully set).
Unattended trains/cars are also chocked.
Where there are enough cars (once I get to four on our local trains, I run out of cars anyhow), I can see setting enough to hold for a static test, then maybe a couple more. This could involve several trips between the cars and the locomotive, however.
Once a number has been established through repeated tests, though, I would opine that the guidelines would include that "finagle factor" so the operation would then be reduced to set and test. If conditions are such that the established number does not do the job, then more brakes, which should include that "finagle factor" should be set. If the number in the guideline is supported by sufficient testing, however, that should rarely, if ever, be necessary.
I've mentioned it a couple of times in these discussions, but that doesn't mean it's been brought up officially. I would opine that this may well have been the case in one form or another. Given the engine shutdown factor, it's my opinion that the "straw the broke the camel's back" was loss of the independent brakes, which take their air directly from the main res. No compressor, main res leaks off, independent brakes release, and away we go.
This still goes back to insufficient (or insufficiently set) brakes on the tank cars, as they should have been able to hold the train even without the locomotive brakes.
I mentioned elsewhere that setting 11 brakes on the cars would be 44 axles (assuming setting the hand brake applies brakes on all four axles). Add three axles on each of the five locomotives and you're up to 59. Add the other fifteen axles being held by the independent, and you're up to 74 axles with brakes applied, apparently enough to hold the train. Lose the independent and you're losing 20% of the axles holding the train - very possibly enough to allow the train to roll...
And all that requires is for the firefighters to shut the one running engine down. No other nefarious deeds needed.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
OK we have now really covered the setting of hand brakes. What about the procedure(s) for releasing the brakes when you are a relieving crew that has no idea how they were set up ? Discuss both single person crew & two person crew ? And how are the possibilities that some car hand brakes will not set ?
I can see that possibility of a near zero safety factor causing a push-pull test to be unreliable, and maybe that is part of the reasoning by the TSB in saying that test is unreliable.
It seems to me that the issue of a safety factor partly depends on which of these two versions of the test is used:
1) The train is actually pushed or pulled to see how the handbrakes hold.
2) The air brakes are simply released on a standing train to see if the handbrakes hold.
People here have described both procedures.
With #1, you can at least judge how much safety factor there is by the way the push or pull feels.
With #2, there is no way to know how much safety factor there is.
With #2, if you set 15 handbrakes, release the air, and it holds, that only tells you that 15 is enough. If 10 would have held it, then you have 5 extra as a safety factor. But there is no way of knowing how many extra brakes have been set. It might be that 14 would not have held it, so in that case, you would only have one extra brake as a safety factor. It could be an even closer margin than one whole brake. What if the train would have rolled up to the point of having 14.9 brakes set?
Is it safe to leave a train parked on a grade just hanging by a thread so to speak? The equipment cools off, the ambient air temperature changes, the solar heating changes, and wind can kick up. If a train is on a grade with the smallest amount of handbrake safety margin, a cooling contraction of the rails could send a small impulse through the cars standing on those rails. The slightest slack effect created by the impulse of contracting rails could break the holding friction of one or more handbrakes. Once that breaks, the friction begins to fall off. And once that happens the necessary friction will never be regained. The train will roll, and the friction will continue to fall off as the speed increases.
But I am not sure if the Transportation Safety Board of Canada is referring to an uncertain safety factor when they say that it is impossible to know that the train is secured by using the push-pull test. What I find curious about their statement is that they link it with the condition of being on a “high grade.” I don’t understand why that would matter. If you push and pull on a grade, the resistance is going to be higher pushing or pulling up-grade that it will be down-grade. But why not just do the test for the downhill direction since that is the direction that the handbrakes need to work against?
I tried to ask the TSB what they meant by saying that it is impossible to know whether handbrakes would hold from conducting a push-pull test. They would not return the call, and I have since read that they will not engage in any discussions with the public about railroad train brake systems. That is not just in regard to discussion about the MM&A runaway, but the whole train brake subject in general. However, I would guess that the restriction of discussing brakes is based on the fallout of the MM&A runaway.
Yes, but....
Just asking a question here?
If you were to set some brakes on a series of cars and then do the push/pull test, would re-checking the "tightness" of those that were set show that they are still set as they were before?
As I remember of what I have seen of the braking system, there are a lot of chains and eyeloops involved in the linkages from the brake wheel to the brake hangars. Chains and eyeloops are notorious for not extended to the true possible length of the series of loops... rust and imperfections in the contact surfaces tend to seize before two segments reach the deepest interface. Thus, they can be brought to some tension level, but when jarred severely they can then slip past that imperfection and allow some small amount of slop in the tension.
Does the test alter the results?
Bucyrus I tried to ask the TSB what they meant by saying that it is impossible to know whether handbrakes would hold from conducting a push-pull test. They would not return the call, and I have since read that they will not engage in any discussions with the public about railroad train brake systems. That is not just in regard to discussion about the MM&A runaway, but the whole train brake subject in general. However, I would guess that the restriction of discussing brakes is based on the fallout of the MM&A runaway.
TSB and for that matter NTSB are political entities - political entities will not put anything in writing to respond to mere peeons - they could be held accountable for it. The only things they will put in writing are their official reports and don't expect them to explain any inconsistancies that happen to be in them.
Bucyrus jeffhergert Bucyrus Why does the Canadian TSB say that is unreliable? Maybe because it's the simplest explanation. Since the procedure was followed and it moved anyway, the test must be flawed or unreliable. Jeff, Thanks for that clarification about adding a safety factor. Regarding the statement by the TSB of Canada, when you say that “maybe because it’s the simplest explanation,” do you mean explanation of the Lac-Megantic runaway? Actually the TSB made their statement in 2009, so it is not a response to the Lac-Megantic wreck. In 2009, they said this: “Because it is impossible to verify hand-brake effectiveness by pulling or pushing cars on high grades, locomotive engineers cannot accurately know that management's expectations have been met every time cars are secured in accordance with CROR Rule 112.”
I mean in response to the TSB's statement when ever it was made. They must figure if it (P/P test) was done and didn't work, it must therefor be unreliable.
Semper Vaporo Of course, there has been nothing said about a person or persons, unknown, or some other event/circumstance that interfered with the brakes that were set and the number the engineer had set was totally adequate if the external interference had not occurred. I can think of at least one scenario where one of the firemen might have deliberately released the brakes on all the cars so as to prepare to get them moved out of the way, in case the engine fire spread. Then there is the unknown person that came by and did so maliciously. I hope they investigate enough to know for sure they are not just making the Engineer the "goat".
For myself, I haven't ruled out malicious intent on the part of someone releasing hand brakes. Short of a confession, it would be very hard to prove. There are also reasons that the powers that be may want to down play this possibility.
Which is worse, the fact that a railroad employee didn't do his job or that any unattended train could be so easily tampered with? I think the general population will accept a lone screw-up more than an easily accessible rail system. If tampered with, it could have major ramifications, that could cost companies a lot of money to remedy, in the way trains are secured, or cars left in rail yards/sidings/spurs no matter what their size. There's a lot of places where unattended equipment is left.
BucyrusIf the rule requires a crew to set enough handbrakes to hold the train, and if they tested, but still fail to set enough,
Stop there. If they set and test and the train holds, then they have set enough. That's the working definition of "enough" in this case.
Bucyrus...but still fail to set enough, would the rule infraction be forgiven on the basis that the test they performed was unreliable and failed to give the correct information?
If the train doesn't move after the handbrakes are set, yet later the train runs away, then something changed between "then" and "now".
One of those things would have to be the automatic and independent releasing or leaking off. On top of that, there would have to be something more. Maybe a a handbrake mechanism pawl failed. Maybe a trespasser knocked one off. Maybe the temperature rose a lot and the linkage expanded. Maybe the temperature dropped a lot and the linkage hit it's fatigue limit and failed. Maybe there was a bad weld between clevis and rod. Maybe something bumped the train. Maybe a meteor hit the train. (Most likely on CSX, obviously)
Maybe, maybe, maybe all adds up to pretty long odds. The rules rely on redundancy. There is no "fail safe" way to do this.
Bucyrus “Because it is impossible to verify hand-brake effectiveness by pulling or pushing cars on high grades, locomotive engineers cannot accurately know that management's expectations have been met every time cars are secured in accordance with CROR Rule 112.” This is amazing. If the empirical test is unreliable, you don’t have a safe and reliable means to secure trains with handbrakes.
This is amazing. If the empirical test is unreliable, you don’t have a safe and reliable means to secure trains with handbrakes.
"not being met EVERY time" <> reliable. It it possible to have a reliable system the does not work properly EVERY time. Block signals are a good example. You have to define the term "reliable", however.
jeffhergert For myself, I haven't ruled out malicious intent on the part of someone releasing hand brakes. Short of a confession, it would be very hard to prove. There are also reasons that the powers that be may want to down play this possibility. Which is worse, the fact that a railroad employee didn't do his job or that any unattended train could be so easily tampered with?
Which is worse, the fact that a railroad employee didn't do his job or that any unattended train could be so easily tampered with?
Now we're getting somewhere! Where is the real risk and what steps reduce that risk the most?
jeffhergert Bucyrus jeffhergert Bucyrus Why does the Canadian TSB say that is unreliable? Maybe because it's the simplest explanation. Since the procedure was followed and it moved anyway, the test must be flawed or unreliable. Jeff, Thanks for that clarification about adding a safety factor. Regarding the statement by the TSB of Canada, when you say that “maybe because it’s the simplest explanation,” do you mean explanation of the Lac-Megantic runaway? Actually the TSB made their statement in 2009, so it is not a response to the Lac-Megantic wreck. In 2009, they said this: “Because it is impossible to verify hand-brake effectiveness by pulling or pushing cars on high grades, locomotive engineers cannot accurately know that management's expectations have been met every time cars are secured in accordance with CROR Rule 112.” I mean in response to the TSB's statement when ever it was made. They must figure if it (P/P test) was done and didn't work, it must therefor be unreliable. Jeff
Space shuttles are unreliable in a demonstrated way, also, yet we continued to fly them for quite a while after having two of them fail.
Because it is impossible to verify hand-brake ceramic tile effectiveness by inspection in space pulling or pushing cars on high grades, locomotive engineers astronauts cannot accurately know that management's expectations of safe reentry have been met every time cars are secured reentry is attempted
The TSB's statement is not useful or helpful.
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