Lithonia Operator I am wondering: How many engineers, traveling at 100 mph, would put their train into emergency IMMEDIATELY upon seeing a person on the track? You engineers out there, you tell me. It’s an honest question.
I am wondering: How many engineers, traveling at 100 mph, would put their train into emergency IMMEDIATELY upon seeing a person on the track?
You engineers out there, you tell me. It’s an honest question.
Lithonia Operator....I would think that the initial response would be the horn, not the brakes. One would expect the trespasser(s) to hear and react...... But she had so little time to make a decision.
In some locations where kids hang around the tracks, there are frequently instances of the brats playing 'chicken' (I've even seen drivers do it--sit on the tracks until they lose their nerve). If I am sure it is a game of chicken, I'd refuse to play. No horn, no brakes, no worries. Of course, this is from before those pesky event recorders and cameras came onboard.
Lithonia OperatorIsn’t there some danger of the train derailing when put into emergency? And what about any standing passengers? They would get injured, perhaps seriously.
Thanks, Zardoz. Good info.
I doubt that making the emergency application would only increase the time to escape by just a few milliseconds. That seems like an intentional exaggeration to justify not making an emergency application. A few milliseconds? That is a few thousandths of a second. It is not even measurable in practical terms. I think that any realization and escape would have required ½ second minimum. I suspect that an emergency application could have added 2-5 seconds.
Of course, there is no guarantee that a person would suddenly discover the train bearing down on them, even with more time. But the possibility always exists, so the longer the interval, the greater the possibility.
So, what is the big deal about the emergency application being such a sacrifice that it must only be made when there is a certainty that it can save a life?
EuclidSo, what is the big deal about the emergency application being such a sacrifice that it must only be made when there is a certainty that it can save a life?
If you saw the number of 'trespassers' engineers see on the tracks on a daily basis you would be amazed.
Never too old to have a happy childhood!
BaltACD Euclid So, what is the big deal about the emergency application being such a sacrifice that it must only be made when there is a certainty that it can save a life? If you saw the number of 'trespassers' engineers see on the tracks on a daily basis you would be amazed.
Euclid So, what is the big deal about the emergency application being such a sacrifice that it must only be made when there is a certainty that it can save a life?
I have seen a lot of that and completely understand your point. You can't dump the air for every person that pops up along the right of way. The job is actually harder than that. An engineer has to read each situation and react accordingly. Each situation sends a set of signals that add up to whether an emergency application will help and to what extent. Part of the signals are body language, attitude, probable purpose for being on the track, etc.
But it is also possible to adopt what an engineer might consider to be a "safe" policy, and that is to not dump the air until actual impact. The reasoning is that you can't stop in time anyway, so why try unless it is assured to be necessary. That is "safe" because you will never go into emergency without a valid cause. Although this will result in going into emergency after the action has become irrelevant.
An engineer might conclude that since they see so many people on the track and they usually move out of the way, one can conclude that this will be typical. With that kind of conclusion, an engineer is likely to not read the cues of each situation with people on or near the tracks. And then one day, the engineer is surprised when a person does not move out of the way as the engineer always expects them to do.
So the seemingly safe policy proves to be not so safe after all. And it is not a safe policy at all if you end up in court.
Euclid I think that any realization and escape would have required ½ second minimum.
The rule of thumb back in driver's ed was that reaction time was on the order of 3/4 of a second. Now they have to turn and discover what they are reacting to, then move off the tracks, which would be up to 6-7 feet from inside the guage, and at least 4 feet if they were on the tie butts.
A train travelling at 100 fps has moved as much as 500 feet - add propogation time and the time it takes to actually apply the brakes to the wheels/disks, and you're not allowing much leeway.
One uncited source I found said it would take a seven car passenger train doing 80 MPH almost a mile to stop.
A post by an Amtrak passenger on the "Amtrak Unlimited" forum included this: "I heard a muffled PFOOSH! and a couple of seconds or so later you could feel heavy deceleration of the train, " Emphasis mine. The emergency application was reportedly due to a dynamiter in a private car on the train.
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...
tree68One uncited source I found said it would take a seven car passenger train doing 80 MPH almost a mile to stop.
A number of years ago, I was riding home from work on the Metra Southwest Service and was standing in the vestibule waiting for my stop at Oak Lawn. We had just crossed Kostner Ave when the train went into emergency. A semi blocked the crossing at Cicero Ave (about a half mile down) while stopped for a traffic light and we still managed to hit the back end of the trailer.
Speed was about 45-50 MPH with a consist of an F40PH and 7-8 gallery coaches.
There are a number of factors involved, of course. On average, passenger cars will be lighter than freight cars, meaning the coefficient of friction between the car and rail is less. On the other hand, the brakes on a passenger car are going to get better attention than those on a freight car, which should theoretically mean better braking for each car. But I can say from experience that more cars equals more total braking.
Passenger trains, even ranging up to twenty or so cars, are shorter than the average freight train, but the speeds are higher, bringing momentum into the mix - an important consideration.
In the end, it's a complicated mix of factors that are above my meager physics education to evaluate as a package.
It appears the info I found came from the Minnesota Safety Council, which said: The average freight train is about 1 to 1¼ miles in length (90 to 120 rail cars). When it's moving at 55 miles an hour, it can take a mile or more to stop after the locomotive engineer fully applies the emergency brake. An 8-car passenger train moving at 80 miles an hour needs about a mile to stop.
The average freight train is about 1 to 1¼ miles in length (90 to 120 rail cars). When it's moving at 55 miles an hour, it can take a mile or more to stop after the locomotive engineer fully applies the emergency brake. An 8-car passenger train moving at 80 miles an hour needs about a mile to stop.
While I am finding definitive figures for different kinds of Amtrak consist (I suspect the effective braking rate will be very different for Superliners than for Amfleet, for example) there are general rules of thumb for HSR: the maximum achievable deceleration rate is somewhere around 6fpsps (ignoring passenger comfort) if we combine emergency with magnetic track braking just at permissible wheelslide. That produces about a half-mile stopping distance from 120mph, and about a mile and a quarter at 186mph. (This with lighter-weight consists and much better running gear than current Amtrak equipment.)
While I am finding definitive figures for different kinds of Amtrak consist (I suspect the effective braking rate will be very different for Superliners than for Amfleet, for example) there are general rules of thumb for higher-speed trains: the maximum achievable deceleration rate is somewhere around 6fpsps (ignoring passenger comfort) if we combine emergency with magnetic track braking just at permissible wheelslide. That produces about a half-mile stopping distance from 120mph, and about a mile and a quarter at 186mph. (This with lighter-weight consists and much better running gear than current Amtrak equipment.)
You may find this PDF reference from AREMA of some usefulness in understanding how to best implement emergency braking.
zardozCan't speak for 100mph, but I would have zero issues plugging it at 70mph (Metra's top speed).
Zardoz,
Can you provide an estimate of the stopping distance for the type of passenger train that you have run? What would be the stopping distance after making an emergency application on such a train traveling at 80 mph?
Can you also estimate the same for Amtrak #175?
My only emergency braking experience was on a PRR Cincinnati to Chicago passenger train which struck an auto at a grade crossing NW of Hamilton OH. Train consist was E-8, three mail express, three coaches, diner. Knocked the auto into a field and took the MU air hoses off the pilot of the E-8. I was back in a P-70 coach and felt the brakes apply harder than a normal application but not sharply enough to throw anyone to the floor. Took us almost a mile to come to a stop. Two teen agers to the hospital, luckily no fatalities. Had to wait for a welder to arrive and cut a notch in the E-8's pilot which had been bent down to within a half inch of the rail. Watching the welder take pass after pass at that pilot made me realize how thick it was and know I never want to tangle with one. From that example, I comcur with the estimate of almost a mile to stop from 60 mph with brakes in emergency. Now those were iron brake shoes, don't know whether composition shoes have more force. Have had some emergency stops on Metra but they didn't seem any more forceful in their braking effort.
Trains - operating on Signal Indication at track speed ARE NOT line of sight vehicles. There is no way for them to stop WHEN THEY CAN ACTUALLY SEE AND UNDERSTAND what the condition ahead is that will require braking.
A mile away, one can barely see a person, let alone if they are on the tracks, and even if you see them on the tracks, would it be proper to emergency brake the train? A half mile? A quarter mile? When and with what effect.
Every situation is different.The engineer must assess the situation and take proper action.
Here are the essential elements of the question as it pertains to the braking response of #175:
Braking response range was distance from Point A, where victims were first visible to the engineer, to Point B, where victims were struck by the train.
The distance from Point A to Point B is not known, but the time it took to travel that distance is estimated by the engineer to have been 15-20 seconds. Evidence presented in the event recorder data suggests the travel time may have been 10-15 seconds.
If the travel time between Point A and Point B was 20 seconds as the engineer estimated as the longest end of the range, and if the train was averaging 78 mph, the distance from Point A to Point B was 2,288 feet.
The train was being slowed by braking as it traveled from Point A to Point B, but we do not know the rate of deceleration. From the general description of the purpose given by the engineer, I speculate that the deceleration from Point A to Point B was in the range of 3-8 mph reduction in speed.
We do know that the train was traveling 74 mph at Point B when it struck the two victims.
Therefore, if the deceleration between Point A and Point B was 8 mph, the speed at Point A was 82 mph.
The question:
If the engineer had made an emergency application, thus initiating maximum braking at Point A, how much longer would the time interval from Point A to Point B have been?
With the undefined variables involved here, plus the lack of techical specifications for the stopping distance of the train, I see no way to calculate or estimate the answer.
However, it seems to me that the answer to the question may be as high as 2-3 seconds, and extremely unlikely to have been as little as 3 milliseconds.
If an emergency application made at Point A took hold before the train reached Point B, we know there had to have been some lengthening of the time interval for traveling from Point A to Point B without making an emergency application at Point A. So in that case, the answer cannot possibly be zero. I think that some may prefer the answer to be zero, so they estimate a few milliseconds in order to give credibility to the answer being effectively zero.
However 2-3 seconds would have been ample time to recognize the approach of #175 and get clear of it. If the two victims were on the outer tie ends as the engineer of #175 said, they only had to move laterally approximately 2 feet.
Whatever the extra time would have been, we know it was not given.
When running (esp on multi-track territory), it's not uncommon to see people (RRers) working alongside the track such as MOW, C&S, & other train crews.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.
When you can stop you can't see. When you can see you can't stop.
zugmann When running (esp on multi-track territory), it's not uncommon to see people (RRers) working alongside the track such as MOW, C&S, & other train crews.
That is true but what's your point?
An attempt at an overt assassination of character of the Amtrak engineer seems to be occuring. She is not a public figure and one forum member who says he was an engineer expert has been snipping at her lack of what he deemed to be a required action. We also have another member of whom there have been suspicions that he is a (wannabee) researcher for tortious litigations. His questions suggest the possibility. If the CSX employees get a hold of this, it might be a problem in the courts. Amtrak has deep pockets, far deeper than the unfortunate engineer of #175.
charlie hebdoAn attempt at an overt assassination of character of the Amtrak engineer seems to be occuring. She is not a public figure and one forum member who says he was an engineer expert has been snipping at her lack of what he deemed to be a required action.
No overt attempt here chuck, just telling it like it is. She is a 'victim' of Amtrak's hiring and training regimens.
It is not what I deem a required action, IT IS A REQUIRED ACTION.
redacted.
zugmann redacted.
No it wasn't.
Reply byzugmann
Defamation of character is a real thing.
243129 zugmann redacted. No it wasn't. RE: CSX Fatalities Probable Cause, Ivy City, DC Reply byzugmann Defamation of character is a real thing.
It sure is.
charlie hebdo An attempt at an overt assassination of character of the Amtrak engineer seems to be occuring. She is not a public figure and one forum member who says he was an engineer expert has been snipping at her lack of what he deemed to be a required action. We also have another member of whom there have been suspicions that he is a (wannabee) researcher for tortious litigations. His questions suggest the possibility. If the CSX employees get a hold of this, it might be a problem in the courts. Amtrak has deep pockets, far deeper than the unfortunate engineer of #175.
If you believe that questioning the actions of the engineer of #175 is character assassination, I don’t see how you can dismiss the placing of the entire blame for this tragedy on the two victims. All they did was make a minor mistake of distraction during the last ten seconds of their lives.
And yet, there has been a lot of exaggeration of their alleged negligence. We have been told they required protection and acted without it, that they crossed over without 3-step protection, that they lacked common sense, and that they were trespassing.
EuclidAnd yet, there has been a lot of exaggeration of their alleged negligence. We have been told they required protection and acted without it,
that they crossed over without 3-step protection,
that they lacked common sense,
and that they were trespassing.
And you think it is character assassination to question the brake response of the engineer?
Beyond a certain point, yes. It was a rapidly evolving situation and none of us were sitting in that seat.
And I believe that the information presented so far on stopping distance is an indication that little headway would have been taken off the train by an emergency application. The rate of decelleration is not linear.
And the focus on the engineer of 175 is also an indication of another attempt to deflect blame from those who held their own fate in their hands.
charlie hebdo 243129 zugmann redacted. No it wasn't. RE: CSX Fatalities Probable Cause, Ivy City, DC Reply byzugmann Defamation of character is a real thing. It sure is.
So tell me , chuck, how is it defamation?
tree68I think awareness would be the better term, and as neither Amtrak engineer saw them look around, it's a pretty fair conclusion.
All the more reason for an immediate emergency application.
tree68 And you think it is character assassination to question the brake response of the engineer? Beyond a certain point, yes. It was a rapidly evolving situation and none of us were sitting in that seat.
It was a rapidly evolving situation that the engineer could not process rapidly.
"And I believe that the information presented so far on stopping distance is an indication that little headway would have been taken off the train by an emergency application. The rate of decelleration is not linear."
Are you advocating not bothering because the end result will be the same?
tree68And the focus on the engineer of 175 is also an indication of another attempt to deflect blame from those who held their own fate in their hands.
As I stated previously it was a 'perfect storm' of events that led to this tragedy with a major portion of the blame assigned to the two CSX employees.
tree68 Euclid And yet, there has been a lot of exaggeration of their alleged negligence. We have been told they required protection and acted without it, That was an option available to them. They did not use it. that they crossed over without 3-step protection, Hadn't that requirement been rescinded by EHH at that time? that they lacked common sense, I think awareness would be the better term, and as neither Amtrak engineer saw them look around, it's a pretty fair conclusion. and that they were trespassing. I believe that's been established as fact. And you think it is character assassination to question the brake response of the engineer? Beyond a certain point, yes. It was a rapidly evolving situation and none of us were sitting in that seat. And I believe that the information presented so far on stopping distance is an indication that little headway would have been taken off the train by an emergency application. The rate of decelleration is not linear. And the focus on the engineer of 175 is also an indication of another attempt to deflect blame from those who held their own fate in their hands.
Euclid And yet, there has been a lot of exaggeration of their alleged negligence. We have been told they required protection and acted without it,
That was an option available to them. They did not use it.
Hadn't that requirement been rescinded by EHH at that time?
I think awareness would be the better term, and as neither Amtrak engineer saw them look around, it's a pretty fair conclusion.
I believe that's been established as fact.
It's worse. Some folks are besmirching the character of the engineer on 175 who isn't here to defend herself. I think that is dishonorable at best. And they can throw a hissy fit. Who cares.? Not me. Engagement with their like is a waste.
243129Are you advocating not bothering because the end result will be the same?
No - I'm saying that regardless of the actions of the engineer, the results would have been the same. The only difference would have been "at least she dumped the train yadda, yadda, yadda."
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