VOLKER LANDWEHR Euclid I am just curious. Why doesen't PTC prevent collisions at restricted speed? Can it be modified so it can do that? If so, why is that feature omitted? I'm not sure about restricted speed requirements. For me it looks like PTC has to prevent train to train collissions at restricted speed. But I admit that as foreigner I have sometime problems interpreting legal language correctly: https://www.law.cornell.edu/cfr/text/49/236.100549 CFR 236.1005 Requirements of Positive Train Control systems (a)PTC system requirements. Each PTC system required to be installed under this subpart shall: (f)Train-to-train collision. A PTC system shall be considered to be configured to prevent train-to-train collisions within the meaning of paragraph (a) of this section if trains are required to be operated at restricted speed and if the onboard PTC equipment enforces the upper limits of the railroad's restricted speed rule (15 or 20 miles per hour). This application applies to: (1) Operating conditions under which trains are required by signal indication or operating rule to: (i) Stop before continuing; or (ii) Reduce speed to restricted speed and continue at restricted speed until encountering a more favorable indication or as provided by operating rule. (2) Operation of trains within the limits of a joint mandatory directive. Perhaps I read it wrong. Even if it were not required, it shouldn't be a technical problem to design it.Regards, Volker
Euclid I am just curious. Why doesen't PTC prevent collisions at restricted speed? Can it be modified so it can do that? If so, why is that feature omitted?
I'm not sure about restricted speed requirements. For me it looks like PTC has to prevent train to train collissions at restricted speed. But I admit that as foreigner I have sometime problems interpreting legal language correctly: https://www.law.cornell.edu/cfr/text/49/236.100549 CFR 236.1005 Requirements of Positive Train Control systems
(a)PTC system requirements. Each PTC system required to be installed under this subpart shall:
(f)Train-to-train collision. A PTC system shall be considered to be configured to prevent train-to-train collisions within the meaning of paragraph (a) of this section if trains are required to be operated at restricted speed and if the onboard PTC equipment enforces the upper limits of the railroad's restricted speed rule (15 or 20 miles per hour). This application applies to:
(1) Operating conditions under which trains are required by signal indication or operating rule to:
(i) Stop before continuing; or
(ii) Reduce speed to restricted speed and continue at restricted speed until encountering a more favorable indication or as provided by operating rule.
(2) Operation of trains within the limits of a joint mandatory directive.
Perhaps I read it wrong. Even if it were not required, it shouldn't be a technical problem to design it.Regards, Volker
PTC enforces the top end of restricted speed. It will make a penalty application if speed rises above 21MPH. (I've noticed the PTC speedometer, that goes by GPS, is usually 1 to 2 mph slower than the locomotive's speedometer.) Since PTC doesn't know where the obstruction is in the block, it can't stop you short. It only keeps the collision at a relatively slow speed. But still fast enough to cause damage that can lead to, and has led to, fatalities. It will query the position of facing point switches. Which requires the engineer to select the correct position. If no position is selected or the open position is selected, the PTC will then stop the train short.
Jeff
jeffhergert PTC is an overlay on the existing signal system. PTC on the locomotive only "sees" the condition of the signal system ahead. It will see that a block is showing an occupancy, but not what or where the obstruction is. Until every locomotive (head end) and EOT/rear end DPU and every switch is equipped to communicate with the PTC system, there will be a need for human operation at restricted speed in certain situations.
PTC is an overlay on the existing signal system. PTC on the locomotive only "sees" the condition of the signal system ahead. It will see that a block is showing an occupancy, but not what or where the obstruction is. Until every locomotive (head end) and EOT/rear end DPU and every switch is equipped to communicate with the PTC system, there will be a need for human operation at restricted speed in certain situations.
Even after that there will still be a need for human operation, if a block drops for no apparent reason.
Or will trains be prohibited from entering that block in such a situation?
Greetings from Alberta
-an Articulate Malcontent
Do we know if the signals were in service?
Volker, I believe that GCOR 6.27 tells what is basically necessary to know concerning moving at restricted speed:
"When required to move at restricted speed, movement must be made at a speed that allows stopping within half the range of vision short of a train, engine, railroad car, men or equipment fouling the track, stop signal, or derail or switch lined improperly. When a train or engine is required to move at restricted speed, the crew must keep a lookout for broken rail and not exceed 20 MPH. Comply with these requirement until the leading wheels reach a point where restricted speed is no longer required."
My experience as a passenger with restricted speed has been when a train is backing into a station, as when the California Zephyr is backed into the Denver station: one of the train crew is on the ground, lining switches as is necessary, and the other member of the train crew is standing at the rear and continually telling the engineer what the line of sight distance is in carlengths.
It may be psossible to devise an optical sensor that will meet the requirements as well as the human eye can, and translate what is seen into instructions to stop when it is necessary.
Johnny
EuclidI am just curious. Why doesen't PTC prevent collisions at restricted speed? Can it be modified so it can do that? If so, why is that feature omitted?
Modification: perhaps put an optical sensor on the locomotive which will cause the train to stop within one-half of the seeing distance when an obstacle appears?
jeffhergert The current state of PTC won't prevent collisions at restricted speed. People have been killed in restricted speed collisions. Emerson, IA (BNSF) and Clinton, IA (IMRL/BNSF) come to mind. Jeff
The current state of PTC won't prevent collisions at restricted speed. People have been killed in restricted speed collisions. Emerson, IA (BNSF) and Clinton, IA (IMRL/BNSF) come to mind.
I am just curious. Why doesen't PTC prevent collisions at restricted speed? Can it be modified so it can do that? If so, why is that feature omitted?
charlie hebdo BaltACD jeffhergert The current state of PTC won't prevent collisions at restricted speed. People have been killed in restricted speed collisions. Emerson, IA (BNSF) and Clinton, IA (IMRL/BNSF) come to mind. Jeff Every 'quantum leap' in railroad equipment has been sold with the basic premis that it will end all rail accidents in the future. Janney couplersAir brakesAutomatic block signallingCTCand now PTC There are no magic bullets that will eliminate ALL rail accidents. The bullets will eliminate some accidents but will also create ones that are not forseen. As long as humans are involved mistakes will happen. Even when computers are involved one has to remember one thing - computer programming is done by humans. Very true. But as a result of finally adopting each of those safety measures, the accident rate dropped an enormous amount. No one in their right mind would suggest going back to the 1880s.
BaltACD jeffhergert The current state of PTC won't prevent collisions at restricted speed. People have been killed in restricted speed collisions. Emerson, IA (BNSF) and Clinton, IA (IMRL/BNSF) come to mind. Jeff Every 'quantum leap' in railroad equipment has been sold with the basic premis that it will end all rail accidents in the future. Janney couplersAir brakesAutomatic block signallingCTCand now PTC There are no magic bullets that will eliminate ALL rail accidents. The bullets will eliminate some accidents but will also create ones that are not forseen. As long as humans are involved mistakes will happen. Even when computers are involved one has to remember one thing - computer programming is done by humans.
Every 'quantum leap' in railroad equipment has been sold with the basic premis that it will end all rail accidents in the future.
Janney couplersAir brakesAutomatic block signallingCTCand now PTC
There are no magic bullets that will eliminate ALL rail accidents. The bullets will eliminate some accidents but will also create ones that are not forseen.
As long as humans are involved mistakes will happen. Even when computers are involved one has to remember one thing - computer programming is done by humans.
Very true. But as a result of finally adopting each of those safety measures, the accident rate dropped an enormous amount. No one in their right mind would suggest going back to the 1880s.
I am not insinuating that the railroads go back to the 1880's. I am just stating that PTC is not a magic bullet. It is a tool, an advanced one, but a tool never the less. Tools WILL fail; not to the degree that issues happened before the tool was adopted, but there will be incidents where for one reason or another the tool fails. PTC is no different than any other tool.
Never too old to have a happy childhood!
(There was more than just two trains involved here...This one is gonna need a scorecard to sort out all the possible moving parts & growing confusion. Hopefully no more regulatory knee-jerk dictates until all of the investigation is complete. The comments from Chico's grapevine seem to indicate there are a couple additional mysteries to be solved beyond what's been discussed so far.)
Balt:
I always enjoy your observations! Many years ago, a crew into Northtown overlooked a Form B order to call a flagman at a construction site. They were on the wrong radio channel and did not hear said flagman. This had fatal consequences for a City of Minneapolis employee working near a bridge.
Ed Burns
jeffhergertThe current state of PTC won't prevent collisions at restricted speed. People have been killed in restricted speed collisions. Emerson, IA (BNSF) and Clinton, IA (IMRL/BNSF) come to mind. Jeff
ChuckCobleighUnder way at about 8:10 MST, finally. Saw one PHX bound (it would seem) manifest go by while #3 was loading.
It isn't underway. It backed into the position where it had waited before boarding. There it still sits.Regards, Volker
Will have to wait for the details of the crash. However the July Trains (page 15) had a piece about how far along BNSF is on PTC with a huge number of trains already running with it. If this was simply a collision it would be exactly what PTC is supposed to prevent. The Transcon is the first line PTC would be expected on, long though it is.
As a personal aside, to many PTC articles in all media have presented it as a miracle device that could have prevented whatever rail accident is the story of the day. Honest descriptions PTC's performance, limits and cost (include opportunity cost) seem rare.
Chico's grapevine is hearing that a relief crew on a stack train had a situational awareness issue that cost a work train and a track department contract operator dearly. (Human error either with the train crew or the DS having a train flag an absolute signal)
saguaroAmtrak #3 is sitting in Flagstaff,
Under way at about 8:10 MST, finally. Saw one PHX bound (it would seem) manifest go by while #3 was loading.
Amtrak #3 is sitting in Flagstaff, apparently waiting for passengers to be bussed from #4 on the other side of the accident/derailment. So #3 will become #4 and return to Chicago. Apparently there is a BNSF loco on the east end of #3 that will take it to Albuquerque, where the train may be turned. You can see #3 in Flagstaff here (at 8:50am central time on Wednesday they look like they are getting ready to load passengers):
https://www.youtube.com/watch?v=-aNl9W_qaAk
Near Truxton, Tuesday afternoon, details sketchy so far:
https://www.abc15.com/news/region-northern-az/lake-havasu/bnsf-two-trains-derail-northeast-of-kingman
http://www.fox10phoenix.com/news/arizona-news/bnsf-two-trains-derailed-northeast-of-kingman
BNSF Aervice alert:
http://domino.bnsf.com/website/updates.nsf/updates-service-consumer/449128A933E96E6A862582A400157468?Open
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