Paul of Covington How much do we know so far about the cause of this accident? We're discussing everything in the world based on what? I'm still waiting for us to get around to "situational awareness."
How much do we know so far about the cause of this accident? We're discussing everything in the world based on what? I'm still waiting for us to get around to "situational awareness."
I think that was briefly touched on with a comment about a possible missed signal. I'd have to scour the whole thread.
We've gotten a few snippets, but as you say, nothing to give us a firm idea of what did happen.
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...
Shadow the Cats owner In OTR trailers and tractors they're set to apply at 40 psi our low air warning kicks on at 60 psi. They've been mandated here for 40 year's since the 121 airbrake regulations came out.
In OTR trailers and tractors they're set to apply at 40 psi our low air warning kicks on at 60 psi. They've been mandated here for 40 year's since the 121 airbrake regulations came out.
tree68 Paul of Covington How much do we know so far about the cause of this accident? We're discussing everything in the world based on what? I'm still waiting for us to get around to "situational awareness." I think that was briefly touched on with a comment about a possible missed signal. I'd have to scour the whole thread. We've gotten a few snippets, but as you say, nothing to give us a firm idea of what did happen.
Other than it being some kind of braking issue, not much has leaked out. FWIW, someone on another site said the rumor going around his area was that the crew did nothing wrong. This person also pointed out it was close to a spot where a closed anglecock led to a similar collision in 1979. In that one, the crew on the caboose didn't open the emergency valve.
IMO, they have a good idea of what went wrong. They aren't going to say much until they can find a way to place as much blame as possible on the crew. It's been done before where the crew lived. Should be that much easier when the crew didn't. I won't be surprised if the images from the inward facing camera aren't retrievable.
Jeff
For switching it wouldn't be hard especially for yard movements or even moving them at a customer to install a rod that overrode the spring brake when pulled. You already pull a bleeder valve to dump the air out of the tanks now when a train comes into a yard to switch. Put the new one in the same area but it captures the spring brake before the air is dumped out. A good mechaincal engineer could desgn this system in a hurry to work as needed for switching and do as needed in an emergency while applying the KISS principle.
Shadow the Cats ownerFor switching it wouldn't be hard especially for yard movements or even moving them at a customer to install a rod that overrode the spring brake when pulled. You already pull a bleeder valve to dump the air out of the tanks now when a train comes into a yard to switch. Put the new one in the same area but it captures the spring brake before the air is dumped out. A good mechaincal engineer could desgn this system in a hurry to work as needed for switching and do as needed in an emergency while applying the KISS principle.
Roadrailers had spring-type brakes. When there was a problem it would tie up the railroad until the service truck could come out.
Yeah, when air is urniated away it can cause runaways. But locked brakes on a car can cause derailments pretty quickly, too. THis may be a case of a cure worse than a disease. Never minding the whole fact that you are changing one of the core elements of a railcar.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
It may be months before a preliminary NTSB report is released, but seems likely the cause will be either a signal malfunction or a human error by the crew of the moving train.
Shadow the Cats ownerFor switching it wouldn't be hard especially for yard movements or even moving them at a customer to install a rod that overrode the spring brake when pulled.
Railcars don't have anything called a "spring brake".
Dave H. Painted side goes up. My website : wnbranch.com
Retrofitting hundreds of thousands of rail cars to 'have' a spring brake would be far from KISS. Not to mention costly!
Never too old to have a happy childhood!
One could only imagine how crowded the beaches would be as well!! Daytona is already a mess in March/April.
rdamonOne could only imagine how crowded the beaches would be as well!! Daytona is already a mess in March/April.
Well played.
GROAN!
Semper Vaporo
Pkgs.
rdamon One could only imagine how crowded the beaches would be as well!! Daytona is already a mess in March/April.
Can't wait for the “Cars Gone Wild” DVD ads to start on late night TV.
Shadow the Cats owner Euclid Shadow the Cats owner If it comes out that they pissed away their air then look for regulators to say we need to find a way to stop this from happening again. Train brakes work fine as long as they have AIR Pressure. However you lose the air pressure and your screwed. La Magnetic now here in the USA. The railroads are going to have to accept that the continued loss of life is unacceptable in today's society. God forbid a train did the same thing on Cajon Pass again it has happened multiple times in the past. It is time to come up with a failsafe emergency braking system for these things. Not one that if the air pressure is gone won't work one that has a mechanical backup so even if every pound of air is gone it will work. When yarding a train I understand your industry dumps all the air out of the system. When they pull the bleeder rod that could act as the catch for the spring brake to prevent the parking brakes from coming on during the switching process. What's it going to take a full tanker car full of pressurized Cholrine gas being ruptured in another derailment from a train losing air pressure for railroads to see their brakes are not up to what is needed with todays monsters. The prevention of peeing away the air is provided by ECP brakes. I don't quite follow what you are saying about the bleeder rod, spring brake catch, etc. There need not be a mechanical spring brake to achieve the fail safe element that you mention. Even with ECP if that fails the brakes fail back to normal airbrake functions. With a spring brake used for even emergency situations only if the brake pipeline pressure gets below a certain point then the spring overcomes the air and applies the brakes. In OTR trailers and tractors they're set to apply at 40 psi our low air warning kicks on at 60 psi. They've been mandated here for 40 year's since the 121 airbrake regulations came out.
Euclid Shadow the Cats owner If it comes out that they pissed away their air then look for regulators to say we need to find a way to stop this from happening again. Train brakes work fine as long as they have AIR Pressure. However you lose the air pressure and your screwed. La Magnetic now here in the USA. The railroads are going to have to accept that the continued loss of life is unacceptable in today's society. God forbid a train did the same thing on Cajon Pass again it has happened multiple times in the past. It is time to come up with a failsafe emergency braking system for these things. Not one that if the air pressure is gone won't work one that has a mechanical backup so even if every pound of air is gone it will work. When yarding a train I understand your industry dumps all the air out of the system. When they pull the bleeder rod that could act as the catch for the spring brake to prevent the parking brakes from coming on during the switching process. What's it going to take a full tanker car full of pressurized Cholrine gas being ruptured in another derailment from a train losing air pressure for railroads to see their brakes are not up to what is needed with todays monsters. The prevention of peeing away the air is provided by ECP brakes. I don't quite follow what you are saying about the bleeder rod, spring brake catch, etc. There need not be a mechanical spring brake to achieve the fail safe element that you mention.
Shadow the Cats owner If it comes out that they pissed away their air then look for regulators to say we need to find a way to stop this from happening again. Train brakes work fine as long as they have AIR Pressure. However you lose the air pressure and your screwed. La Magnetic now here in the USA. The railroads are going to have to accept that the continued loss of life is unacceptable in today's society. God forbid a train did the same thing on Cajon Pass again it has happened multiple times in the past. It is time to come up with a failsafe emergency braking system for these things. Not one that if the air pressure is gone won't work one that has a mechanical backup so even if every pound of air is gone it will work. When yarding a train I understand your industry dumps all the air out of the system. When they pull the bleeder rod that could act as the catch for the spring brake to prevent the parking brakes from coming on during the switching process. What's it going to take a full tanker car full of pressurized Cholrine gas being ruptured in another derailment from a train losing air pressure for railroads to see their brakes are not up to what is needed with todays monsters.
If it comes out that they pissed away their air then look for regulators to say we need to find a way to stop this from happening again. Train brakes work fine as long as they have AIR Pressure. However you lose the air pressure and your screwed. La Magnetic now here in the USA. The railroads are going to have to accept that the continued loss of life is unacceptable in today's society. God forbid a train did the same thing on Cajon Pass again it has happened multiple times in the past. It is time to come up with a failsafe emergency braking system for these things. Not one that if the air pressure is gone won't work one that has a mechanical backup so even if every pound of air is gone it will work. When yarding a train I understand your industry dumps all the air out of the system. When they pull the bleeder rod that could act as the catch for the spring brake to prevent the parking brakes from coming on during the switching process. What's it going to take a full tanker car full of pressurized Cholrine gas being ruptured in another derailment from a train losing air pressure for railroads to see their brakes are not up to what is needed with todays monsters.
The prevention of peeing away the air is provided by ECP brakes.
I don't quite follow what you are saying about the bleeder rod, spring brake catch, etc. There need not be a mechanical spring brake to achieve the fail safe element that you mention.
Even with ECP if that fails the brakes fail back to normal airbrake functions. With a spring brake used for even emergency situations only if the brake pipeline pressure gets below a certain point then the spring overcomes the air and applies the brakes. In OTR trailers and tractors they're set to apply at 40 psi our low air warning kicks on at 60 psi. They've been mandated here for 40 year's since the 121 airbrake regulations came out.
So, if I understand you, the trucking industry uses straight air brakes with the use of stored spring force to provide a backup brake activation in case there is a loss of the air pressure normally used for braking.
Train air brakes are not a straight air system. They have their own version of failsafe backup. I do not think the train brake system would readily translate into the spring backup used by the trucking industry. The main element that needs backup is the pressurized air delivery line of a straight air brake system. Train brakes originated as a straight air brake system, but they found they needed a backup in case the train broke in two, which was very common and still is.
When this need for backup system for train braking became obvious, they could have added springs to the cylinders and switched functions around so that the straight air caused the cylinders to release the brakes by overcoming the spring pressure. But they also needed to use the brakes for gradual stopping and not just for emergencies. For gradual stopping, braking force must be modulated, and the spring application would need additional complex mechanism to achieve and control brake force modulation.
So the railroads adopted a novel appoach of using the train line to deliver air to a working brake system on each car with its own reservoir to store the air needed to power that independent brake system on each car. Once the train line nourished all the reservoirs with air to power their individual brake systems on each car, the train line was transformed into a pneumatic control line to tell the car reservoirs when to use their air to set the brakes. The pressure of the control train line was reduced in order to cause this application of the car reservoir air to power the brake cylinders on each car.
That fundamental principle meant that if a train broke in two and parted its pressureized train line, it would cause an application of the train brakes rather than render the train brakes inoperative as would be the case with a straight air brake system and its pressurized train line.
Also, if ECP brakes do fail, they do not revert back to air brake functions of the conventional train air brake system, as you say. ECP brakes can fail in various way, but not in the manner of peeing away the air like can happen with conventional train air brakes.
Euclid, not quite how OTR air brakes work. In those the spring applies the brakes. Air releases the brakes. No air no movement.
Going off STCO comment, I agree that adding a spring wouldn't be complicated, pricey perhaps. A complete redesign could use the emergency reservoir to hold off the spring and if the reservoir runs out the spring would apply. A lockout mechanism for switching would be easy to add here.
Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction
ruderunnerI agree that adding a spring wouldn't be complicated, pricey perhaps. A complete redesign could use the emergency reservoir to hold off the spring and if the reservoir runs out the spring would apply. A lockout mechanism for switching would be easy to add here.
Before this goes too much further, we've had this discussion before, and like a whack-a-mole it seems to keep coming up when persistence of memory fades.
Spring brakes were a popular invention over a century ago, along with things like the Loughridge chain brake that seem attractive until you actually try them and start to see the problems. (See John White on rubber car springs, for a different example of something that keeps cropping up and then disappearing as the technology evolves).
Any spring brake powerful enough to hold a modern railroad car will be capable of causing problems if it inadvertently deploys while running. However, making it even more powerful to serve as an emergency brake is more of a disaster than those who aren't familiar with the physics are likely to know.
Then there is the issue of making a mechanism that reliably pulls the spring brake off, considering how any accumulated slack in the foundation rigging was accommodated in application, while ensuring that it re-applies when safety calls ... but doesn't fail unsafe. I think it's a reasonably safe bet that such a thing would be no less hard to pull off than a current handbrake is to apply, and there is the thought looming that you'd also have to allow the spring-brake mechanism to be cinched further down into engagement for formal car securement (in other words, positive ratcheting engagement both ways). We've also discussed the 'idea' of having motor engagement and disengagement via a dedicated trainline or power plugs of some sort, which apparently is now technically feasible (although, on reflection, I think still a lunatic idea)
My take on this is that for the price of the spring brake, especially a motorized or servo one, you can equip several cars with convertible ECP. And have something eventually useful.
The spring for our emergancy and parking brake is contained in the emergency brake chamber itself. If there is NO air pressure to overcome the spring pressure we can not move. http://www.consulab.com/products/specifications/ec12753145e.pdf
Here is how our brake chambers are arranged. We pay on average for one without the rods 80 bucks with the rods 120. They survive anything we throw at them. They handle being beat on with hammers in the winter when frozen up and if they fail they fail to the released not the applied why the springs have a pair of weak points put in that break that allow the spring to collaspe so the affected vechile can be moved to a repair shop. Time to replace is less than 30 mins normally.
Overmod ruderunner I agree that adding a spring wouldn't be complicated, pricey perhaps. A complete redesign could use the emergency reservoir to hold off the spring and if the reservoir runs out the spring would apply. A lockout mechanism for switching would be easy to add here. Before this goes too much further, we've had this discussion before, and like a whack-a-mole it seems to keep coming up when persistence of memory fades. Spring brakes were a popular invention over a century ago, along with things like the Loughridge chain brake that seem attractive until you actually try them and start to see the problems. (See John White on rubber car springs, for a different example of something that keeps cropping up and then disappearing as the technology evolves). Any spring brake powerful enough to hold a modern railroad car will be capable of causing problems if it inadvertently deploys while running. However, making it even more powerful to serve as an emergency brake is more of a disaster than those who aren't familiar with the physics are likely to know. Then there is the issue of making a mechanism that reliably pulls the spring brake off, considering how any accumulated slack in the foundation rigging was accommodated in application, while ensuring that it re-applies when safety calls ... but doesn't fail unsafe. I think it's a reasonably safe bet that such a thing would be no less hard to pull off than a current handbrake is to apply, and there is the thought looming that you'd also have to allow the spring-brake mechanism to be cinched further down into engagement for formal car securement (in other words, positive ratcheting engagement both ways). We've also discussed the 'idea' of having motor engagement and disengagement via a dedicated trainline or power plugs of some sort, which apparently is now technically feasible (although, on reflection, I think still a lunatic idea) My take on this is that for the price of the spring brake, especially a motorized or servo one, you can equip several cars with convertible ECP. And have something eventually useful.
ruderunner I agree that adding a spring wouldn't be complicated, pricey perhaps. A complete redesign could use the emergency reservoir to hold off the spring and if the reservoir runs out the spring would apply. A lockout mechanism for switching would be easy to add here.
As brakes where out on trains I am sure they adjust the brakes we do the same.
Shadow the Cats ownerAs brakes wear out on trains I am sure they adjust the brakes we do the same.
Of course they do; the key is to examine the way that is done on railroad cars and translate that into what would be required of a spring-brake mechanism. A good starting point is slack adjusters.
One consequence in the 'old days' was that the actual spring have very long travel (e.g. many turns for a coil or helical spring). If I recall correctly some designs had a spring running a significant part of the length of the car. When I was a kid and first found out about cold-gas generators in rocketry, I thought some kind of pressurized accumulator with gas generation was an answer to providing reservoir pressure or effective application quickly in emergencies; I still think that represents a "better" safety approach than mechanical springs pulled off by active service pressure. But it retains many of the objections associated with those approaches.
Shadow the Cats ownerAs brakes where out on trains I am sure they adjust the brakes we do the same.
Part of the Terminal Air Test performed by Car Inspectors is to measure Brake Piston Travel with the brakes applied (I believe in excess of 9 inches is a failure) and to replace worn out brake shoes that they observe. When a car has all new brake shoes (nominally 8 per car - 4 shoes per truck, ie. one brake shoe per wheel or two brake shoes per axle) the brake piston travel is well under 9 inches. This is how brakes get adjusted when a train is built - this will also happen when a train undergoes the required 1000 mile inspection.
jeffhergert Other than it being some kind of braking issue, not much has leaked out. FWIW, someone on another site said the rumor going around his area was that the crew did nothing wrong. This person also pointed out it was close to a spot where a closed anglecock led to a similar collision in 1979. In that one, the crew on the caboose didn't open the emergency valve. IMO, they have a good idea of what went wrong. They aren't going to say much until they can find a way to place as much blame as possible on the crew. It's been done before where the crew lived. Should be that much easier when the crew didn't. I won't be surprised if the images from the inward facing camera aren't retrievable. Jeff
NTSB preliminary report:
https://www.ntsb.gov/investigations/AccidentReports/Pages/RRD19FR001-preliminary-report.aspx?fbclid=IwAR1Pk0ox2CdOIhCudL1SJMCw9Eq56quQ2mkC9LgeGmTjleXi6DbcCTl_NyY
I would like to know why the EOT didn't dump the tail end.
Greetings from Alberta
-an Articulate Malcontent
SD70Dude NTSB preliminary report: https://www.ntsb.gov/investigations/AccidentReports/Pages/RRD19FR001-preliminary-report.aspx?fbclid=IwAR1Pk0ox2CdOIhCudL1SJMCw9Eq56quQ2mkC9LgeGmTjleXi6DbcCTl_NyY I would like to know why the EOT didn't dump the tail end.
Very perplexing - the head end was reading the air pressure being sent by the EOT but the EOT didn't respond to the Emergency activation from the head end. Evidence that there was at least one way communication between the EOT and the head end.
BaltACD SD70Dude NTSB preliminary report: https://www.ntsb.gov/investigations/AccidentReports/Pages/RRD19FR001-preliminary-report.aspx?fbclid=IwAR1Pk0ox2CdOIhCudL1SJMCw9Eq56quQ2mkC9LgeGmTjleXi6DbcCTl_NyY I would like to know why the EOT didn't dump the tail end. Very perplexing - the head end was reading the air pressure being sent by the EOT but the EOT didn't respond to the Emergency activation from the head end. Evidence that there was at least one way communication between the EOT and the head end.
Upon reading the report again, it doesn't say if the Engineer tried to use the emergency toggle switch on the HOT/IDU console.
Even though placing the automatic brake valve in emergency should have also triggered an emergency application from the EOT, in reality those systems don't always work together perfectly, especially on older locomotives.
The apparent loss of brake pipe continuity while the train was moving - quite possibly every single time the slack was bunched up - is far more disturbing. It reminds me of Jeff's story from not so long ago about an air hose being pinched by a drawbar.
If everything else was working properly, and if the engineer made an emergency application, but the end of train device failed to duplicate that emergency application at the same time the engineer made his, would not the whole train still go into emergency braking?
It sounds like they are saying that the engineer’s emergency application did not propagate to the entire train, or it may not have applied on any of the train.
Euclid If everything else was working properly, and if the engineer made an emergency application, but the end of train device failed to duplicate that emergency application at the same time the engineer made his, would not the whole train still go into emergency braking?
It should have.
Euclid It sounds like they are saying that the engineer’s emergency application did not propagate to the entire train, or it may not have applied on any of the train.
Yes, exactly.
I'm presuming the EOT had an turbine in it - how many CFM would that normally consume?
If a hose was, indeed, pinched, that would tend to explain why the pressure displayed by the EOT dropped as it did, why there was an air flow of zero, and why the reduction, as well as the emergency application, did not propogate through the entire train.
Will the investigation be able to determine the number of cars that had the emergency application ? That location should be able to determine where the apparent brake pipe pinch occurred ? Maybe it even happened on a loco ?
More important is why the loss of communication to the EOT occurred ? According to the preliminary report communication from the EOT was maintained ? That has many possible worries for operation of these extra long trains ?
I'm presuming the EOT had an turbine in it - how many CFM would that normally consume? The number will need to be compared to the volume of the trains brake pipe especially if any pinch occurred.
blue streak 1More important is why the loss of communication to the EOT occurred ? According to the preliminary report communication from the EOT was maintained ?
Communications is normally bidirectional. Can one direction fail? Loco hearing EOT but EOT not hearing Loco? Larry, you are a ham radio op, any thoughts on this.
Wherever the air flow got obstructed - the actions of the train that were described - would make it appear that the obstruction was very near the head end of the train and that little if any train braking was being had from the portion of the train that was ahead of the obstruction and would have had brakes being applied.
It is not mentioned, what if any observations that the crew may have communicated about seeing brakes applied on any portion of their train - activated brakes should have developed some level of smoke (that would have been hard to see in the dark) or what was observed of the applied brakes creating 'rings of fire' around the wheels that were being actively braked. Investigation of the scene by NTSB should be able to identify among the derailed cars, those that had wheel tread bluing from the excess heat generated from the applied brakes.
Air Turbine EOTs don't normally take enough air to cause air flow to register. That air flow was changing with the change in slack condition is not unusual. We call that a slip joint.
On another site, someone with more experience with that area said that loss of comm with the EOTs is common. You can lose comm and not know it for 16 mins 30 seconds before the head end device registers comm loss. (If you think you are out of comm, you can press the comm test key. It will come back with currents status.) An EOT not registering a pressure change after a brake application/release is usually a good indicator that you don't have comm.
Our rules call for operation of the eot emergency toggle switch, even if showing a no comm status. Just in case comm momentarily is established.
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