TREE68,You still don't understand the brake system. With the pressure maintaining feature cut in, that is exactly what it will do, maintain equalizing reservoir pressure. If there happens to be a leak, it will maintain that leak (up to a point), keeping the brakepipe at a constant level. If there is an excess of pressure it will exhaust it.
Let's say you couple up to a cut of cars on ground air and let's say that ground air is set at 80psi. When you couple up and before the conductor turns the air in, you draw the equalizing pressure down to 65psi. When the conductor turns the air in, it starts blowing out of the brake stand because 80psi is greater than the 65psi that you have the brake drawn down to because that maintaining feature is trying to do what you asked it to do. It will continue to blow until the ground air is taken out.
So, we have established that the maintaining feature does its job. The unit happens to get shut down while the brake handle is still in the same position where it previously gave that reduction to 65psi. The air starts to leak off of the main reservoir. As the pressure in the main reservoir starts leaking below the equalizing reservoir pressure, the maintaining feature will still try to do its job and the equalizing pressure follows the M/R right on down, taking the brakepipe pressure right along with it and applying the brakes more and more until a full service application is reached. After that, even though the brakepipe may leak down to 0 psi, no more brake can be applied to the train and the air is just wasting away. Guess what happens if the unit gets restarted!!!
Now going back to where we coupled up to the train, cut out the maintaining feature and watch what happens to the brakepipe pressure. It goes up the 80psi of the ground air. Why? Because you just cut out its only means of escape...the maintaining feature. In other words, you just bottled the air. If there happened to be any air brakes on the cars, they will release.
Bucyrus,
I assume that you would have the brakes set just as if they had dynamited into full emergency.
So why did they even leave the engine running in the first place?
.
Thanks for that explanation Ed. I am familiar with most of those details, but I was not quite clear on the condition of the trainline with brakes applied, train standing, with engine coupled to it, with the angle cock of the engine and the one on the first car open, and engine running.
I suppose you could have some pressure in the trainline if brakes were applied in a service application. But if you are leaving a train, I assume that you would have the brakes set just as if they had dynamited into full emergency.
So the trainline would be exhausted and maximum pressure would be in the cylinders. And the trainline would be open to atmosphere at the brake valve in on the locomotive. So under those conditions, what if that train stood like that for a month or more? I know that if you set out cars, and dump the air, it will eventually leak off from the pressurized cylinders. Some may leak off in only a matter of a few hours, and some may hold for several days or weeks. When I refer to the brakes leaking off, I do not mean brakes releasing from reservoir leakage into a closed trainline.
Considering the standing train with engine running, and brakes full applied with trainline open to atmosphere, I assume there would be no way for the running engine to recharge or maintain a charge in the brake cylinders if air gradually leaked off of that pressurized portion of the circuit on each car.
If that is true, then it would have been completely irrelevant that the fire department shut off the MM&A engine that was running. The running engine would have been completely disassociated from any role in maintaining pressure in the brake cylinders. And even if that pressure leaked off over time, say three weeks, the running engine would still not be able to compensate for that loss of air pressure in the cylinders.
But being that the brakes were released in only an hour or so, we could probably 100% rule out the possibility that the cylinders leaked off as I described above. So I see your point that the only way the brakes could have been released is for somebody to have released them from the engineer’s brake valve or to have closed the lead angle cock of the first car if the engine was uncoupled, or closed that angle cock and/or the one on the engine if the engine remained coupled. And then for the brakes to have released under any of those scenarios, there would need to be some leakage from one or more reservoirs into the closed trainline, which could release all of the brakes just like an intentional release would.
edblysardLeaving the locomotives train brake handle in the application zone keeps the entire train line open to atmosphere, preventing this from happening.
Actually, I believe having the brake handle in the application zone brings to bear the pressure maintaining apparatus of the brake system (unless you're running a really old locomotive). If you've made a 20 pound reduction, the system will maintain 70 PSI in the trainline even in the face of any leaks that may occur.
Moving the brake handle (further) into application vents air from the train line to atmosphere, but the air brake stand/system will still maintain pressure on the train line, up to a point.
That's why one must cut out the brake stand in order to do a leakage test on the train.
Moving the brake handle to emergency does completely open the trainline to atmosphere.
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...
Schuylkill and Susquehanna The train is now believed to have stuck the "crowded bar" after derailing and while on fire. There is now a criminal investigation into the causes of the accident. S&S
The train is now believed to have stuck the "crowded bar" after derailing and while on fire.
There is now a criminal investigation into the causes of the accident.
S&S
Yes, some person or persons is probably going to do prison time for this one. They should. Even if it was just a mistake. Somebody either deliberately acted to release the brakes, negligently acted to release the brakes, or didn't set the brakes properly.
The result was that a whole lot of folks burned up. And that is unacceptable. And likely criminal.
Bucyrus BigJim As long as that handle was in the brake application position, having the locomotive running or not makes not a bit of difference to the brakes, they will stay applied until someone moves the handle to the equalize (release)setting, or closes the anglecock on the lead car, which might allow enough air to leak from the cars reservoirs to begin equalizing the pressure and slowly releasing the brakes, but in the time frame mentioned, that would have to be a major leak and on more than one car.Finally, somebody that understands how train brakes work! Pay attention folks!Thanks Ed As Ed has said, if there was still continuity in the trainline and the brakepipe pressure hadn't been drawn down a good bit below "Full Service" to begin with, anything that would have caused a rise in the brakepipe pressure of just a pound and a half over whatever the brakepipe reading was at the time could have triggered a brake release on every car in the train. Just to be clear, I was not disagreeing with you earlier when I posted something that was contrary to what you had explained. I was only posting what the president of the railroad had said. He said that shutdown of the engine released the brakes. But personally, I am fine with your explanation. Although I do have one question: With the train standing like it was (with the locomotive coupled to the train), what would be the proper condition of the trainline? Would it be completely exhausted and open to atmosphere? If so, I don't understand the concern over reservoir leakage raising the trainline pressure and causing a release. How could leakage raise the trainline pressure if it were open to atmosphere?
BigJim As long as that handle was in the brake application position, having the locomotive running or not makes not a bit of difference to the brakes, they will stay applied until someone moves the handle to the equalize (release)setting, or closes the anglecock on the lead car, which might allow enough air to leak from the cars reservoirs to begin equalizing the pressure and slowly releasing the brakes, but in the time frame mentioned, that would have to be a major leak and on more than one car.Finally, somebody that understands how train brakes work! Pay attention folks!Thanks Ed As Ed has said, if there was still continuity in the trainline and the brakepipe pressure hadn't been drawn down a good bit below "Full Service" to begin with, anything that would have caused a rise in the brakepipe pressure of just a pound and a half over whatever the brakepipe reading was at the time could have triggered a brake release on every car in the train.
As long as that handle was in the brake application position, having the locomotive running or not makes not a bit of difference to the brakes, they will stay applied until someone moves the handle to the equalize (release)setting, or closes the anglecock on the lead car, which might allow enough air to leak from the cars reservoirs to begin equalizing the pressure and slowly releasing the brakes, but in the time frame mentioned, that would have to be a major leak and on more than one car.
As Ed has said, if there was still continuity in the trainline and the brakepipe pressure hadn't been drawn down a good bit below "Full Service" to begin with, anything that would have caused a rise in the brakepipe pressure of just a pound and a half over whatever the brakepipe reading was at the time could have triggered a brake release on every car in the train.
Just to be clear, I was not disagreeing with you earlier when I posted something that was contrary to what you had explained. I was only posting what the president of the railroad had said. He said that shutdown of the engine released the brakes. But personally, I am fine with your explanation.
Although I do have one question: With the train standing like it was (with the locomotive coupled to the train), what would be the proper condition of the trainline? Would it be completely exhausted and open to atmosphere? If so, I don't understand the concern over reservoir leakage raising the trainline pressure and causing a release. How could leakage raise the trainline pressure if it were open to atmosphere?
The cars themselves each have a reservoir…equal pressure in the train line and the cars reservoir keep the brakes off.
The main reservoir on the locomotive is used to release the brakes, not apply them, it and the compressor charge the train line pressure (and in the case of a train with zero air pressure in both the train line and the cars reservoirs, it will charge the cars reservoirs first) up to that of the individual cars reservoir, equalizing the two side of the system and releasing the brakes.
Drop the train line pressure, the brakes apply, using compound leverage they apply a tremendous amount of force to the wheels.
The brake valve on each car will also use some of the air in each cars reservoir to recharge the train line, this speeds up the equalizing (release) process, once the pressure is equal in both sides the brakes release.
If, and only if both ends of the train line were closed to atmosphere, could some of the air in the cars reservoirs leak back into the train line, and as little as a 2 psi difference between the cars reservoirs and the train line can allow the brakes on that car begin to release, such a release would “travel” from car to car from the point of the leak, slowly releasing the brakes on each car.
The reason you leave the anglecock open on a standing cut of cars is to insure that if there is a leaking car reservoir, any air leaked out will vent to atmosphere…with the angle cock closed, this leak will build pressure in the train line, if you have a couple of leaks, it could easily build up enough pressure in the train line to begin releasing the brakes.
It would take time for this to happen, several hours to several days.
For this to be the cause of this accident, there would have to be a lot of leaks, and they would have to be pretty good sized leaks to cause it to happen as quickly as an hour to two hours as the time frame suggests.
Leaving the locomotives train brake handle in the application zone keeps the entire train line open to atmosphere, preventing this from happening.
What would have to happen to release the air brakes on the cars would be either someone moved the brake handle in the lead unit to the release position, thus closing the train line and allowing air from the locomotives reservoir and compressor to begin flowing into the train line, equalizing the two sides of the brake system, and releasing the brakes, or…someone closed the anglecocks on both the locomotive and the lead car, un coupled the glad hands and then opened the anglecock on the lead car, which leaves the train line vented to atmosphere, negating the chance of any leakage or flow back from the locomotive.
All that would be required after that is to walk the train, pulling the release handles on the brakes valves, causing each car’s reservoir to vent to atmosphere.
The brake valve vents the reservoir directly to the atmosphere when the handle is pulled.
Because the train line is open to atmosphere, and the reservoirs are now opening to atmosphere, both sides of the system are equalized, so the brakes on each car will release as each handle is pulled.
As each car was bled off, its brakes would release, do this far enough back down the train and gravity will eventually take over.
23 17 46 11
Murphy Siding If the fire department shows up at the railroad tracks to put out a fire on a locomotive, who would have the knowledge, and/or authority to shut off the locomotive? You'd sure as heck think that the fire department would contact somebody at the railroad, if they were putting out a fire on a locomotive on that railroad's tracks.
Yes, they would contact the railroad. And EVERY FIREFIGHTER and EMT *knows* how to shut down a locomotive if they went to a railroad sponsored training class. I have been to several such classes, and have shut down the locomotive using the throttle, the master switch in the cab, and the cut off switch by the fuel tank.
ROAR
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overall Just to make sure I understand, did the train roll backward into Lac-Magentic? Had the train passed through it and then climbed a grade? Did the train stop at the top of the grade and then catch fire? I haven't seen any kind of track diagram as to where everything is. I apologize if this was covered elsewhere.
Just to make sure I understand, did the train roll backward into Lac-Magentic? Had the train passed through it and then climbed a grade? Did the train stop at the top of the grade and then catch fire? I haven't seen any kind of track diagram as to where everything is. I apologize if this was covered elsewhere.
Dan
Ulrich I wouldn't leave my car in idle and unlocked on a hill.
The difference between motor vehicles and locomotives is the reverser. A car can't idle without its key, a locomotive can idle without its reverser. The reverser, when removed, doesn't allow anyone to move the locomotive, as it can't be put "into gear". (meaning no electricity can be sent to the traction motors)
Hope this helps,
NW
Maybe leaving an idling train on a siding with no one on board is not such a great idea? I wouldn't leave my car in idle and unlocked on a hill. Why is it safe to leave a 10 thousand ton train this way? In this day and age of cell phones, Facebook, tweeting and whatever else, can't crews coordinate more precisely so that they can meet each other without leaving the train unattended? Is it THAT hard to do? A friend of mine drives a super B tanker for Esso. I asked him if he ever leaves his fuel laden rig parked on a hill, unlocked, and idling...his response was "you f@#&*$* kidding me?"
hellwarrior If you want to see a video of the first ten minutes of the accident, just look at this link from Radio-Canada. You will be shocked.
If you want to see a video of the first ten minutes of the accident, just look at this link from Radio-Canada. You will be shocked.
Reposted as a link:
http://www.radio-canada.ca/nouvelles/societe/2013/07/09/003-video-images-francais-temoin-lac-megantic.shtml
Modeling the Pennsy and loving it!
edblysard Bucyrus Here is a question for all you hand brake experts: If a hand brake had been applied on a tank car prior to the runaway, would the brake wheel and rachet still indicate an applied brake if the trucks were separated from the car during the wreck? The ratchet may still be cranked, but no guarantee it would remain that way, and with the trucks gone from under the car, there would be no way to tell if the bakes had been applied or not, unless the wheel set showed signs of sliding a long distance.
Bucyrus Here is a question for all you hand brake experts: If a hand brake had been applied on a tank car prior to the runaway, would the brake wheel and rachet still indicate an applied brake if the trucks were separated from the car during the wreck?
Here is a question for all you hand brake experts: If a hand brake had been applied on a tank car prior to the runaway, would the brake wheel and rachet still indicate an applied brake if the trucks were separated from the car during the wreck?
The ratchet may still be cranked, but no guarantee it would remain that way, and with the trucks gone from under the car, there would be no way to tell if the bakes had been applied or not, unless the wheel set showed signs of sliding a long distance.
daveklepper But the locomotive handbrake and several cars worth of handbrakes would have prevented a runaway. If Ed Burkhardt knew that an oil tankcar train was left unmanned, what would his reaction be? If no tragedy had occured? Is it normal on YOUR railroad for an oil tankcar train to be left unmanned under any circumstance? Yes, fuel oil trains, ethanol trains, trains with some god awful chemicals that make crude oil look like a nice thing…the only cars we have to keep “under scrutiny”(the TSA;s term) are TIH cars, toxic inhalation cars, chlorine, ammonia, cyanide. We have 24 hours from the time they enter our yards/property to have these cars placed in their respective plants, and once returned to us, 24 hours to have them in an outbound train. Inbound Class 1 conductors have a receipt we must sign taking possession of these cars, we also have a receipt we make the receiver sign when we place these car in their facility, and we have a receipt the outbound conductor must sign taking possession again for the Class 1 carrier when they leave our property. They are not allowed to be left anywhere the general public can get to then. I would imagine that out in uninhabited areas, it would not be a problem to leave these cars in a train consist parked in a siding, but in urban and industrial areas where public access is possible, they are not to be left un attended, unless in a locked fenced area. Recall that two different plots against Canadian railroads have been foiled by Canadian police in the recent several months. After the fire was extinguished, did police prevent anyone from approaching, to preserve evidence, etc.? Depends on what type of fire…if it was a simple engine room fire, contained to the engine room, most likely no one would stick around and guard the thing afterward…keep in mind if it was a older GE, these things aren’t called toasters for no reason. How many Dash 9s have you seen with the scorch marks on the long hood, about midway, just under the exhaust stack? These had a fuel injector hose leak, sprayed diesel on the hot exhaust manifold, and poof goes the Dash 9. Very common occurrence, and unless the fire appeared deliberately set, there would be no real reason to leave someone to watch it, especially if the locomotive was turned off. If they had done so, the moment the train began to move, an alarm would have been sounded.
But the locomotive handbrake and several cars worth of handbrakes would have prevented a runaway.
If Ed Burkhardt knew that an oil tankcar train was left unmanned, what would his reaction be? If no tragedy had occured?
Is it normal on YOUR railroad for an oil tankcar train to be left unmanned under any circumstance?
Yes, fuel oil trains, ethanol trains, trains with some god awful chemicals that make crude oil look like a nice thing…the only cars we have to keep “under scrutiny”(the TSA;s term) are TIH cars, toxic inhalation cars, chlorine, ammonia, cyanide.
We have 24 hours from the time they enter our yards/property to have these cars placed in their respective plants, and once returned to us, 24 hours to have them in an outbound train.
Inbound Class 1 conductors have a receipt we must sign taking possession of these cars, we also have a receipt we make the receiver sign when we place these car in their facility, and we have a receipt the outbound conductor must sign taking possession again for the Class 1 carrier when they leave our property.
They are not allowed to be left anywhere the general public can get to then.
I would imagine that out in uninhabited areas, it would not be a problem to leave these cars in a train consist parked in a siding, but in urban and industrial areas where public access is possible, they are not to be left un attended, unless in a locked fenced area.
Recall that two different plots against Canadian railroads have been foiled by Canadian police in the recent several months.
After the fire was extinguished, did police prevent anyone from approaching, to preserve evidence, etc.?
Depends on what type of fire…if it was a simple engine room fire, contained to the engine room, most likely no one would stick around and guard the thing afterward…keep in mind if it was a older GE, these things aren’t called toasters for no reason.
How many Dash 9s have you seen with the scorch marks on the long hood, about midway, just under the exhaust stack?
These had a fuel injector hose leak, sprayed diesel on the hot exhaust manifold, and poof goes the Dash 9.
Very common occurrence, and unless the fire appeared deliberately set, there would be no real reason to leave someone to watch it, especially if the locomotive was turned off.
If they had done so, the moment the train began to move, an alarm would have been sounded.
cv_acrAs noted previously, there's a lot of oil and other crap that builds up inside an old engine that is quite easily flammable...
This.
If the fire was on the ground, under the locomotive, or otherwise outside the mechanical spaces, I'd tend to be suspicious.
We run vintage locomotives - most aren't known for being "tight..." You can only keep them so clean.
The train line brake handle in the locomotive vents the train line to atmosphere, it allows all the air in the line to escape, which applies the brakes.
Locomotives are left running for several reasons, and depending on their age, have a auto start/stop system that shuts them off to conserve fuel.
The most common reason to leave a locomotive running are to keep the batteries charged up, and to keep the main reservoir charged, which lessens the time required to release the brakes once the train is ready to move….other reasons are most locomotives have a gravity fed cooling system, they have no thermostat or antifreeze, and diesel engines shut off in cold weather are often very hard to start, in fact, the block may freeze and crack if the water temp drops below freezing.
As for the “shut off locomotive” theory, it would be more dangerous to leave them running, because all it would take is someone moving the brake handle to the wrong position to recharge the brake line and release the brakes, cut away, the train would go into emergency braking, and unless someone closed the leading or open anglecock, it would stay that way unless someone bleeds off the brakes.
My bet is the FD tried to move the locomotives, (burning locomotive, tank cars full of oil, sounds like an idea!) and pulled the pin, (maybe, maybe not)while someone in the lead unit tried to move handles around to make the locomotives move, and they ended up releasing the trainsbrakes instead.
On locomotives with a standard control stand, the train brake and the independent brake handles are stacked, one above the other, and if moving one didn’t accomplish what they wanted, moving the other one to see if that worked makes sense, so it is possible for both the train brake and the independent brake to be released….once the fire was out and the FD gone, the hand brakes on the cars failed to hold the cut, the whole thing could have rolled back and taken off, the locomotives may have gone along for the ride until the cars began moving a little faster, they break away, the locomotives go into emergency and stop where they are, the train (cars) goes into emergency and slides a few thousand feet further, possible derailing because of the emergency brake application, and here you have a cut of cars derailed from and separated from the locomotives.
Not the greatest explanation, it has several variations, but it works….
The news we badly didn't want to hear. The death toll has risen to 15:
http://www.ctvnews.ca/canada/dispatchers-weren-t-alerted-about-runaway-train-15-confirmed-dead-dozens-missing-1.1359434
Bruce
So shovel the coal, let this rattler roll.
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Bucyrus I am doubting the fleeting reports that the engines were uncoupled from the train. I suspet that this is distorted information referring to the fact that the engines separated from the train as the cars piled up in the derailment. Hence the engines were found "uncoupled from the train."
I am doubting the fleeting reports that the engines were uncoupled from the train. I suspet that this is distorted information referring to the fact that the engines separated from the train as the cars piled up in the derailment. Hence the engines were found "uncoupled from the train."
I agree. There's really been nothing (except wild uninformed speculation) to suggest that the engines were at any point deliberately uncoupled from the rest of the train. The separation occurred during the wreck.
Chris van der Heide
My Algoma Central Railway Modeling Blog
daveklepper Any locomotive fire should raise suspicion unless an engineer or other competent railroad person can explain to the Fire Chief exactly how the fire started. But apparently the train crew were not present.
Any locomotive fire should raise suspicion unless an engineer or other competent railroad person can explain to the Fire Chief exactly how the fire started. But apparently the train crew were not present.
Suspicion of what exactly?
As noted previously, there's a lot of oil and other crap that builds up inside an old engine that is quite easily flammable, and MMA is not known for rostering brand new modern power.
mistertrainsEven with the "fire on the locomotive" scenario that seems to be emerging, it appears that somebody had to have uncoupled the tank cars from the locomotives. If so, and at that point, an appropriate number of cars' handbrakes should have been set.
The fire seems to be adequately confirmed. Also confirmed is the fact that the handbrakes did not prevent the train from rolling.
It is similar to the earlier distortion that the train was operated by some sort of remote control, which apparently arose from the reports that the runaway train was un-manned, which of course it was.
The head C/O of the railway said no more trains will be left unattended, you may see the resurgence of cabooses in the near future on certain trains.
If the hand brake is applied, there will be evidence of the actuating chain being pulled to the brake actuation device - either the hand wheel or ratchet lever mechanism, even when the trucks have become deatached from the car..
Never too old to have a happy childhood!
The idea of posting a security guard at the location of the stopped train was the first thing that came to mind when I heard about this runaway. But there are just so many different versions coming out right now, that it is hard to understand exactly what happened. Bottom line: The railroad is the source of the disaster, if not the cause, and will get blamed for any damage done to life and property.
blownout cylinderThe death toll now is at 14.
I think there is one fact all of us have a responsibility for, it is to get the number of fatalities right. At this point I see nothing that has raised the number above 13. If and when more bad news does arrive, I would hope whoever sees it would provide a link to the source of the information.
But aside from that: On my dream railroad and possibly on your real railroad, the whole scenareo would have been different. 1. An oil tank train would never be left unattended. Who knows, possibly a truck could swerve off a nearby highway and run into the side? 2. Any train left unattended in above freezing weather would have the necessary number of handbrakes set and the engine shut down. And on your railroad?
This would not have prevented deliberate mayhem, but would have ruled out anything else.
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