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Re: LA Times story on Metrolink vs BNSF incident at Rialto [link]
Author: OldPoleBurner
Date: 11-22-2008 - 15:26
Yes, in answer to your question, on board recorders do time stamp brake applications, brake pipe pressure changes, speed, throttle position, etc. and that information will enable the NTSB, or anyone else with access, to gain a complete picture of the when- where-how of crew actions and equipment responses to these actions.
"My brakes failed" or "The throttle stuck" are the oldest dodges in the book! But the NTSB will discover the facts in yet another accident investigation. We will know for sure only then. But what difference will it make, if Metro-Link's contractor continues to employ unreliable people to run the trains?
Even if there was a problem with the brakes, the distance between successively restrictive aspects includes a very large margin to account for various possible brake problems. That distance is verified safe by a calculation called the "Worst Case Braking Profile Calculation". Moreover, the latest any qualified engineer would have noticed such a brake problem would be as he passed the approach signal, where an immediate full service brake application is required by rule. That would have been plenty of time and distance for an emergency dump should a problem have been promptly noticed.
I suppose that an angle cock might have been left closed, making train brakes ineffective. But the initial brake test, if made, would have revealed that. Even so, full emergency locomotive braking should have been sufficient on a light passenger train, if applied soon enough after the train failed to respond as the yellow was passed.
One thing that I do not understand: is the notion that calling signal aspects to a conductor not in the cab adds anything real to safety. This could so, only if the conductor wasn't distracted by his passenger related duties, each and every signal aspect was visible and verifiable to him, and he was physically near the emergency brake cord at the time an error occurred. Since he can't even tell for himself when a signal was passed, let alone see its aspect, and he is always busy with the passengers, and brake cords are sparse, he cannot realistically be expected to enforce signal compliance at all !
As I said in a post about the last MetroLink crash, either there must be two competent enginemen in the cab, calling aspects to each other and actively enforcing compliance; or there must be an automatic device to enforce compliance with signals. In this case, we see that two in the cab was still not enough! But were they competent professionals, as someone back a few posts seriously questioned.
But even competent professionals can and do make mistakes - just not very often. But what are the odds that two competent professionals will make the same booboo at the same time. Unless in this case, these people in fact lacked competence, those odds are obviously still not good enough. Now how reliable your backup method actually is, comes into full question; whether it be a second engineer, or an automated enforcement device such as ATC, PTS, PTC, or even FM (frickin' magic). Any automated backup must obviously be more reliable that a second human. Actually, it being "Failsafe" is required - A tough row to hoe for any system designer!
--------------------------------------
In that regard, I recently had an opportunity to observe such a system in full operation - in all it's splendor. While visiting family about a hundred twenty miles north of Salt Lake City, I took my 11 year old grandson on an excursion aboard Utah's new FrontRunner commuter line. I seem to have already made an avid railfan out of him. We were fortunate to find a seat at the very front in the cab car; where we could see out the left front window, observe the engineer and an FRA inspector riding along, and hear most everything said in the cab. I gave my grandson a detailed explanation of how it all worked as we went along. (that's how you interest your kids in railroading - spend time with them doin' it).
We observed how all wayside signals had been eliminated except at control points, in favor of cab signals. These cab aspects displayed the maximum permissible speed in actual numerals (pure speed signaling), taking into account location of preceding trains ahead, CP signal aspects, curvature, station platform speed limits, etc.
We observed the speed aspects being immediately and precisely enforced - to the letter. The engineer had to be on his toes, as we soon discovered. While at 79 mph, we received a "40mph" aspect due to a diverging route ahead, setting alarms off. Almost immediately, the engineer dumped the throttle and applied full service brakes - the alarms quieted. As we approached target speed, he partially released the brakes to flare in right at 40mph. But he did it just a little too soon (at about 45 mph), resulting in more alarms and a full service dump to a screeching halt (irretrievable braking). This in front of the FRA observer! But the FRA did get to see how tight the enforcement really was. Of course, the engineer immediately made the requisite report of his error over the radio, while he was waiting for the controls to reset.
Mind you, this system uses conventional microprocessor based track circuits available off the shelf. They are simply configured correctly for a full function ATC system to work, even without intermediate signals. What was fascinating to watch was the precision of the system and its boundaries, and the precise enforcement of all safety related matters. Absolute precision in enforcement are both critical here, as they run about 40 trains a day in each direction, on mostly single track - and on time (within a couple of minutes).
Not only was there absolute train separation and civil speed limit enforcement, but every single grade crossing for forty five miles was built to federal "Quiet Zone" standards, with either four quadrant gates or high center median barriers. Also at each grade crossing, were lunar aspects indicating whether all four gates were down, or whether exit gates were prevented from dropping for any reason. The engineers were blowing their horns anyway, whenever visiblity was restricted
All in all, an impressive ride - and already a crowded one. And a very impressive demonstration of a full function ATC system. A model for the industry, in fact!
It did this tired old signal engineer's heart good to see it actually come to pass in its fullness.
CalTrain in California is already preparing for installation of an almost identical system, utilizing similar technology (actually in planning even before the Chatsworth accident).
Now, Metro-Link: I say again; GET ON WITH IT !
OPB
"My brakes failed" or "The throttle stuck" are the oldest dodges in the book! But the NTSB will discover the facts in yet another accident investigation. We will know for sure only then. But what difference will it make, if Metro-Link's contractor continues to employ unreliable people to run the trains?
Even if there was a problem with the brakes, the distance between successively restrictive aspects includes a very large margin to account for various possible brake problems. That distance is verified safe by a calculation called the "Worst Case Braking Profile Calculation". Moreover, the latest any qualified engineer would have noticed such a brake problem would be as he passed the approach signal, where an immediate full service brake application is required by rule. That would have been plenty of time and distance for an emergency dump should a problem have been promptly noticed.
I suppose that an angle cock might have been left closed, making train brakes ineffective. But the initial brake test, if made, would have revealed that. Even so, full emergency locomotive braking should have been sufficient on a light passenger train, if applied soon enough after the train failed to respond as the yellow was passed.
One thing that I do not understand: is the notion that calling signal aspects to a conductor not in the cab adds anything real to safety. This could so, only if the conductor wasn't distracted by his passenger related duties, each and every signal aspect was visible and verifiable to him, and he was physically near the emergency brake cord at the time an error occurred. Since he can't even tell for himself when a signal was passed, let alone see its aspect, and he is always busy with the passengers, and brake cords are sparse, he cannot realistically be expected to enforce signal compliance at all !
As I said in a post about the last MetroLink crash, either there must be two competent enginemen in the cab, calling aspects to each other and actively enforcing compliance; or there must be an automatic device to enforce compliance with signals. In this case, we see that two in the cab was still not enough! But were they competent professionals, as someone back a few posts seriously questioned.
But even competent professionals can and do make mistakes - just not very often. But what are the odds that two competent professionals will make the same booboo at the same time. Unless in this case, these people in fact lacked competence, those odds are obviously still not good enough. Now how reliable your backup method actually is, comes into full question; whether it be a second engineer, or an automated enforcement device such as ATC, PTS, PTC, or even FM (frickin' magic). Any automated backup must obviously be more reliable that a second human. Actually, it being "Failsafe" is required - A tough row to hoe for any system designer!
--------------------------------------
In that regard, I recently had an opportunity to observe such a system in full operation - in all it's splendor. While visiting family about a hundred twenty miles north of Salt Lake City, I took my 11 year old grandson on an excursion aboard Utah's new FrontRunner commuter line. I seem to have already made an avid railfan out of him. We were fortunate to find a seat at the very front in the cab car; where we could see out the left front window, observe the engineer and an FRA inspector riding along, and hear most everything said in the cab. I gave my grandson a detailed explanation of how it all worked as we went along. (that's how you interest your kids in railroading - spend time with them doin' it).
We observed how all wayside signals had been eliminated except at control points, in favor of cab signals. These cab aspects displayed the maximum permissible speed in actual numerals (pure speed signaling), taking into account location of preceding trains ahead, CP signal aspects, curvature, station platform speed limits, etc.
We observed the speed aspects being immediately and precisely enforced - to the letter. The engineer had to be on his toes, as we soon discovered. While at 79 mph, we received a "40mph" aspect due to a diverging route ahead, setting alarms off. Almost immediately, the engineer dumped the throttle and applied full service brakes - the alarms quieted. As we approached target speed, he partially released the brakes to flare in right at 40mph. But he did it just a little too soon (at about 45 mph), resulting in more alarms and a full service dump to a screeching halt (irretrievable braking). This in front of the FRA observer! But the FRA did get to see how tight the enforcement really was. Of course, the engineer immediately made the requisite report of his error over the radio, while he was waiting for the controls to reset.
Mind you, this system uses conventional microprocessor based track circuits available off the shelf. They are simply configured correctly for a full function ATC system to work, even without intermediate signals. What was fascinating to watch was the precision of the system and its boundaries, and the precise enforcement of all safety related matters. Absolute precision in enforcement are both critical here, as they run about 40 trains a day in each direction, on mostly single track - and on time (within a couple of minutes).
Not only was there absolute train separation and civil speed limit enforcement, but every single grade crossing for forty five miles was built to federal "Quiet Zone" standards, with either four quadrant gates or high center median barriers. Also at each grade crossing, were lunar aspects indicating whether all four gates were down, or whether exit gates were prevented from dropping for any reason. The engineers were blowing their horns anyway, whenever visiblity was restricted
All in all, an impressive ride - and already a crowded one. And a very impressive demonstration of a full function ATC system. A model for the industry, in fact!
It did this tired old signal engineer's heart good to see it actually come to pass in its fullness.
CalTrain in California is already preparing for installation of an almost identical system, utilizing similar technology (actually in planning even before the Chatsworth accident).
Now, Metro-Link: I say again; GET ON WITH IT !
OPB
