ATLANTIC CENTRALWhen cab signals came along nobody said "lets take down all the signal masts"?
In what alternate universe do you live, or what is your excuse for not having read contemporary accounts of cab-signal development?
The very existence of automatic-block signaling in the first place is a compromise and a kludge, properly recognized as such by Frank Sprague before 1911. As soon as continuous-aspect cab signals became practical there was no need for all the color light aspects to convey block occupancy, and even relatively little for home and distant aspects for fixed hazards. When continuous-aspect has speed control, even primitive two-speed control, associated with it, it is comparatively simple to incorporate a 'zeroth speed' (throttle modulation to zero, gear to mid or drift, brakes to service) corresponding to passing a wayside point rather than a 'red indication' -- that requiring inductive or ramp infrastructure in addition to the tone modulation for the cab aspects, but not all the complex relays and power circuits needed to work wayside lights for blocks in either direction.
ATLANTIC CENTRALAs explained over and over by me and others, the old system, had it been working, would have prevented this crash.
Yes, but not others like Amtrak 501.
What Overmod formulated first and I took up in my question is mentioned in the FRA cost-benefit analysis of PTC, IIRC. A number of independent industry experts criticized the railroads for asigning the signal department with the PTC development and thus giving away the named possible advantages.
Rolling block would rise the track capacity without the need of more track.
Where is the back-up for the signal system? If equipment fails, it is designed failsafe. And the same can be done with PTC.
BTW the European Train Control System (ETCS) will, in its advanced form, remove the need for lineside signals and allow a movable/rolling block.Regards, Volker
SealBook27Wasn't there a similar accident in SC a few years ago; a misaligned switch resulting in a collision between two freight trains?
The incident at Graniteville, SC is the reason we now have things like the SPAF.
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...
VOLKER LANDWEHR BaltACD I suspect trying to interface relay dependent circuitry with electronic circuitry can be a real adventure. My guess is that the railroads felt it was more economic and more reliable to do a 'clean installation' of 21st Century signal technology when installing equipment to support PTC requirements. My question is why designing a PTS system based on GPS and then not use the advantages like e.g.: lineside signals only in specific locations, rolling block? Is the chosen PTC system in this light really the most cost effective?Regards, Volker
BaltACD I suspect trying to interface relay dependent circuitry with electronic circuitry can be a real adventure. My guess is that the railroads felt it was more economic and more reliable to do a 'clean installation' of 21st Century signal technology when installing equipment to support PTC requirements.
My question is why designing a PTS system based on GPS and then not use the advantages like e.g.: lineside signals only in specific locations, rolling block?
Is the chosen PTC system in this light really the most cost effective?Regards, Volker
I did lots of control work (not railroad signals) back in relay days and in the early days of solid state - we interfaced the two with no problem.
I'm not really up to date on any of this, but the idea of abandoning line side signals and relying completely on GPS and similar wireless communication seems like a really bad idea.
Rolling blocks beyond the current permissive signals also sounds like a really bad idea.
Equipment does fail, I don't care relay or solid state, radio or hard wire. Redundant with specific absolutes seems like a good idea.
When cab signals came along no body said "lets take down all the signal masts"?
Why should PTC be any different?
As explained over and over by me and others, the old system, had it been working, would have prevented this crash.
Sheldon
My understanding is that the civilian use of GPS does not have the required precision to be dependable in reliabily differentiating between #1 and #2 track at any given location, the track centers of each track are within the allowable margin of error.
CSX has a number of locomotives that are equipped with lateral accelerometers to find and report 'rough spots' in the track structure. These locomotives transmit a message to the MofW Desk in Jacksonville with the GPS derived coordinates of the incident that triggered the message. When communicated to the MofW Supervisor for the particular territory the proviso is that ALL tracks in the area must be inspected for the defect - the GPS precision is not sufficient to indicate the specific track.
The Military used of GPS may be more precise than Civilian - I don't know.
Never too old to have a happy childhood!
BaltACDI suspect trying to interface relay dependent circuitry with electronic circuitry can be a real adventure. My guess is that the railroads felt it was more economic and more reliable to do a 'clean installation' of 21st Century signal technology when installing equipment to support PTC requirements.
rdamonI would assume that the Searchlight signals have proven fairly reliable in their years of service given how many were in deployed. They failsafe mode is to move to restricting, but I could see where a stuck mechanism could give a false clear. I think the signal manufacturer lobby may have been successful in legislation to accelerate its demise.
My guess and that is all that it is - a guess.
The railroads are installing new signals and the equipment that is necessary for the signals to operate and report required information in the PTC enviornment is that the existing installed signals and relay cases are all 40-50-60-70 years old or older and parts aren't getting any more plentiful as time moves on. All the installed signal base relys on relays, not electronics. Relays take some time to operate. I can recall riding the dome car on the Capitol Limited and watching the signals - the train, at track speed, would be 3 or 4 car lengths past the signal before the signal dispay changed from Proceed to Stop.
I suspect trying to interface relay dependent circuitry with electronic circuitry can be a real adventure. My guess is that the railroads felt it was more economic and more reliable to do a 'clean installation' of 21st Century signal technology when installing equipment to support PTC requirements.
I would like to point out that I think we have been mistaken in our saying that certain signals (those with moving parts) won't work with PTC. The truth is they will. (Where we have PTC in effect in my area there are still a handfull of searchlight type signals in service. I haven't heard if they will be replaced before the deadline or if they have a waiver allowing them to remain.) I believe they are "outlawed" for use with PTC because if the moving part of the searchlight signal should for some reason become stuck, it could allow a false proceed signal. PTC is just an overlay on existing signal systems. The onboard display only "knows" where the engine is. It doesn't know where other trains are or really where the rear end of it's own train is. Because EOTs are not incorporated to PTC, the system is dependent on accurate measurements being entered into the system when initialized or updated after work events. It does "see" signals ahead of it. (approach-lit signals will be turned on for the six miles ahead of the train.) You could just use a fixed limit of authority (like a track warrant for example) but then you would only be able to have one train within the limits at any time, unless you eant everything to run at restricted speed. We don't have "rolling block" capability yet.
So I don't think we still have signals because the railroads only want to keep their signal departments on. (You probably could get rid of intermediate waysides-CNW did when they installed ATC. But they still had signal maintainers because you still have all the rest of the signal and track circuits to maintain.)
Jeff
I notice that Bella is pointedly absent from this investigation so far.
The reason for implicating "PTC" as a cause is not quite direct enough. As prominently noted in the early years of the mandate, none of the functions of PTC really involve lineside signaling at all; in fact, as with earlier approaches such as tone-modulated cab signals it makes lineside signals except in very specific and location-related circumstances less than useless.A very great deal of the time and rigmarole spent on implementing "PTC", specifically including the work that caused this signal suspension, is actually railroads keeping their signal departments and signal-related contractors in business in spite of what PTC would provide after the cutover. Often for what might be called 'political reasons' including the relative power signal departments wield within railroad management.
Now I have little doubt that "PTC implemented by the mandated deadline" would have prevented this accident, and not just because any required 'signal suspension' to accomplish that would have been over and done with years ago. But that is not a valid argument except in the minds of blamers.
On the other hand, were PTC not mandated, there would have been no need to convert signals to work with it, which was the stated reason. As as Balt has stated, the existing signal system would have detected both the initial throwing of the switch and the subsequent failure to reline it even after telling the dispatcher in essence it had been relined -- that is something that signal-system engineers have been proud of detecting for many, many years -- and there would have been much more likely than not ample warning for 91 to stop, intact and clear of the switch let alone the CSX train.
I expect that NTSB will acknowledge that efforts toward mandated PTC compliance were an integral part of the accident cause, but that it was not 'wrong' either to do the work in a way resulting in a signal suspension or to go to manual working during the period of suspension. And I think that it is true that much of the manual procedure would have been adequate ... had it been applied correctly. Sadly, it appears that relative stupidity and failure of familiarity with manual train-handling procedures is involved in more than one proximate cause of this tragedy.
VOLKER LANDWEHRAs looks currently if CSX personnel had worked properly that accident would have been prevented. Regards, Volker
Regards, Volker
Human failure is human failure - no matter the system
BaltACDSorry pally! If 'off the shelf' PTC systems would have solved the interoperatability problems of the Class 1 carriers + Amtrak and all the various commuter rail agencies it would have been adopted in a heartbeat. Such was not the case.
I didn't talk about PTC. In the years before the mandate the railroads could have formulated the requirements. In Germany there was the PZB90 available, an intermittent cab signaling and train protection system. https://en.wikipedia.org/wiki/Punktf%C3%B6rmige_Zugbeeinflussung#Germany
It is used on lines with speed limits up to 100 mph.
Yes there were a number of systems in Europe. These systems are older than the European Union. So even better, the American Railroads had a number of system to choose the best from.
Locomotives that run across a border into another safety system area are equipped accordingly.
If I remember correctly run-through locomotives sometimes needed special equipment of neighboring railroads in the USA too.
BaltACDIf PTC equipment wasn't being installed, the existing signal system would not have been suspended and the open switch would have been detected by that signal system.
As looks currently if CSX personnel had worked properly that accident would have been prevented.Regards, Volker
BaltACD If PTC equipment wasn't being installed, the existing signal system would not have been suspended and the open switch would have been detected by that signal system.
If PTC equipment wasn't being installed, the existing signal system would not have been suspended and the open switch would have been detected by that signal system.
And above where you first brought this up, you say that this means that PTC caused the collision because the signals had been suspended in order to install PTC. You said that PTC has claimed its first deaths. That is absolute nonsense.
I think it is possible for PTC to cause an accident due some type of PTC failure, but that is not what happened here. What most apparently caused this collision (if proven) was a failure to re-line the switch for the mainline.
VOLKER LANDWEHR tree68 Nah - In reality, whatever caused the temporary shutdown of the signal system was a factor in the incident. In this case, it was PTC. Perhaps NTSB judges PTC as contributing factor for sure not as the primary cause. But I doubt it. I expect that they state PTC would have prevented the crash.Regards, Volker
tree68 Nah - In reality, whatever caused the temporary shutdown of the signal system was a factor in the incident. In this case, it was PTC.
Perhaps NTSB judges PTC as contributing factor for sure not as the primary cause. But I doubt it. I expect that they state PTC would have prevented the crash.Regards, Volker
Keep spinning - I am sure the NTSB will. It has taken 2 days for the media to get clued in that the cause of the Signal Suspension was for installation of PTC equipment in the field.
tree68Nah - In reality, whatever caused the temporary shutdown of the signal system was a factor in the incident. In this case, it was PTC.
VOLKER LANDWEHR BaltACD Typical PR spin being cast upon the unknowing. We can spin it around again and again. There were less expensive system just look outside the USA to Europe or Japan. Even the simpler systems (compared to high-speed line systems) would have been good enough for the typical speeds. For me it looks like someone with a bias (CSX) is blaming PTC.Regards, Volker
BaltACD Typical PR spin being cast upon the unknowing.
We can spin it around again and again. There were less expensive system just look outside the USA to Europe or Japan. Even the simpler systems (compared to high-speed line systems) would have been good enough for the typical speeds.
For me it looks like someone with a bias (CSX) is blaming PTC.Regards, Volker
Sorry pally! If 'off the shelf' PTC systems would have solved the interoperatability problems of the Class 1 carriers + Amtrak and all the various commuter rail agencies it would have been adopted in a heartbeat. Such was not the case. In the USA all the Class 1 carriers + Amtrak operate as a true national railroad system with equipment operating equally well on any of the lines. The locomotives that operate under PTC for CSX in New York are expected to perform the same service for BNSF or UP in California. European systems are a collection of fifedoms and equipment from on fifedom cannot operate successfully on another fifedom's territory.
The CSX entity, with the current vulture capitalist management, has much too shakey of a footing the Federal agencies of government to blame it on PTC. However, the facts speak for themselves. If PTC equipment wasn't being installed, the existing signal system would not have been suspended and the open switch would have been detected by that signal system.
BaltACDIf the Signal System had not been suspended for PTC equipment installation the existing signal system would have prevented the incident.
That is probably true, but so what? That is not at all the same as your original statement that PTC has claimed it's first deaths. In that statement, you are blaming the crash on PTC.
VOLKER LANDWEHRFor me it looks like someone with a bias (CSX) is blaming PTC.
Nah - In reality, whatever caused the temporary shutdown of the signal system was a factor in the incident. In this case, it was PTC.
ANY working signal system would have helped prevent this incident.
BaltACDTypical PR spin being cast upon the unknowing.
VOLKER LANDWEHR tree68 If it weren't for the PTC installation, there wouldn't have been a signal suspension... On the other hand if PTC was already installed according to NTSB news video this accident might have been prevented depending on how the switch was implemented into the system. If the railroads had implemented a lot safer safety system PTC wouldn't be necessary. If all had worked according to rules this accident would have been prevented. So blaming PTC is just distracting from the real causes possibly lying at CSX.Regards, Volker
tree68 If it weren't for the PTC installation, there wouldn't have been a signal suspension...
On the other hand if PTC was already installed according to NTSB news video this accident might have been prevented depending on how the switch was implemented into the system.
If the railroads had implemented a lot safer safety system PTC wouldn't be necessary.
If all had worked according to rules this accident would have been prevented.
So blaming PTC is just distracting from the real causes possibly lying at CSX.Regards, Volker
Typical PR spin being cast upon the unknowing.
If the Signal System had not been suspended for PTC equipment installation the existing signal system would have prevented the incident.
tree68If it weren't for the PTC installation, there wouldn't have been a signal suspension...
tree68 Euclid I don’t see how operating negligence during a signal suspension for a PTC installation is the fault of PTC. If it weren't for the PTC installation, there wouldn't have been a signal suspension...
Euclid I don’t see how operating negligence during a signal suspension for a PTC installation is the fault of PTC.
If it weren't for the PTC installation, there wouldn't have been a signal suspension...
"PTC has claimed its first deaths, as the Signal Suspension was to allow the installation of equipment required to support PTC in the future on this line."
EuclidI don’t see how operating negligence during a signal suspension for a PTC installation is the fault of PTC.
BaltACD Euclid BaltACD PTC has claimed its first deaths, as the Signal Suspension was to allow the installation of equipment required to support PTC in the future on this line. That is a spectacular stretch. No stretch at all. If it wasn't for PTC the signals that existed at Dixiana could have lasted for years without the need for replacement and a Signal Suspension to perform the work. For all I know there may have been some deaths among the signal gangs that are removing the old equipment and installing the new equipment.
Euclid BaltACD PTC has claimed its first deaths, as the Signal Suspension was to allow the installation of equipment required to support PTC in the future on this line. That is a spectacular stretch.
BaltACD PTC has claimed its first deaths, as the Signal Suspension was to allow the installation of equipment required to support PTC in the future on this line.
That is a spectacular stretch.
No stretch at all. If it wasn't for PTC the signals that existed at Dixiana could have lasted for years without the need for replacement and a Signal Suspension to perform the work. For all I know there may have been some deaths among the signal gangs that are removing the old equipment and installing the new equipment.
tree68 Deggesty Was it reported WHY the signals were out of service? It was reported early on that there was a signal suspension while work was being done preparatory to cutover of PTC. The outage was intentional.
Deggesty Was it reported WHY the signals were out of service?
It was reported early on that there was a signal suspension while work was being done preparatory to cutover of PTC. The outage was intentional.
There was an AP item in this morning's paper (Salt Lake City Tribune) about the wreck which gave the reason why the signal system was not in use. There was also a little history of the whole matter from the wreck in California on, stating, not in great detail, why the railroads did not rush down to the corner store and buy everything necessary and put it into use immediately.
Perhaps the writer actually talked with someone who knew what and why--and had an understanding of what she was told?
Johnny
CandOforprogress2 Even the old switches that date back to the 1930s near my house on the Erie have signal actuaters that are solid state. What could have gone wrong here?
Even the old switches that date back to the 1930s near my house on the Erie have signal actuaters that are solid state. What could have gone wrong here?
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DeggestyWas it reported WHY the signals were out of service?
CMStPnP BaltACD In the limits of a of Signal Suspension They are even reporting on Fox News today the signals were out of service and that it was a manually thrown switch that was not aligned correctly leading the Amtrak train into the waiting Freight Train on the siding. So the News Media has finally caught up with your original comments.......took them some time though.
BaltACD In the limits of a of Signal Suspension
They are even reporting on Fox News today the signals were out of service and that it was a manually thrown switch that was not aligned correctly leading the Amtrak train into the waiting Freight Train on the siding. So the News Media has finally caught up with your original comments.......took them some time though.
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