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What's wrong with PTC

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  • Member since
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  • From: US
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Posted by BaltACD on Monday, March 13, 2017 7:22 AM

Paul Milenkovic
BaltACD
Paul Milenkovic

As with anything in this world - The Devil is in the Details!  Details!  Details!  Details!  Those pesky details!  If it wasn't for the details, perpetual motion machines would be on the market yesterday.

Maybe you and I speak a different language?

The problem with perpetual motion machines is in a hard physical law "Conservation of Energy."  OK, Einstein wrote "E=mc^2", matter got converted into energy, and big booms happened, but at least that energy came from somewhere instead of from nothing.  But apart from nuclear reaction converting matter into energy, perpetual motion machines are not a matter of pesky details.  To say that is to suggest that perpetual motion is doable if the government gives the key people a little more time (or even a lot more time to work on details).

The problem with PTC is not the problem with a working perpetual motion.  There are no laws of physics that need to be violated for it to work.

Maybe a better comparison is between PTC and controlled nuclear fusion?  There is no new physics to discover with nuclear fusion, everyone says it is "just around the corner", but it is always 15-20 years away.  Nuclear fusion is awash in details.  Such as the scientists know how to build a fusion power plant right now by scaling up their fusion experiments that don't yet achieve "break even", but the plant would be many times the size and expense of the known fission-type atomic power plant, and fission atomic power at present is hopelessly uneconomic.

Maybe PTC is impossible in that it would require Artificial Intelligence to account for all of the contingencies of where a train needs to be stopped?  Maybe the specifications for PTC make it an "NP-hard" computer programming problem, which is a term of art among computer scientists of a problem lacking an exact solution in a reasonable time even with the fastest computers foreseeable in the future?  Maybe PTC is impossible in the way that replacing the current, creaky computerized Air Traffic Control system is impossible because there are too many cooks stirring the pot drafting up rules and specifications that it is supposed to meet?

But saying that we don't have perpetual motion machines on account of pesky details is claiming that we will have perpetual motion once enough time goes by that all the details get worked out, of which scientific opinion (yes, opinion because there can always be some new discovery) claims will never happen.

Maybe in your line of work saying "PTC is like perpetual motion" means something to people and settles an argument.  In my line of work, saying "PTC is like perpetual motion" only gets the arguments started.  In my work community, people worry a great deal about being precise in what we mean in such statements.

mere physics is just a detail Big Smile  for all those who think PTC and Perpetual Motion Machines are easy.

Never too old to have a happy childhood!

              

  • Member since
    January 2001
  • From: Atlanta
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Posted by oltmannd on Monday, March 13, 2017 10:02 AM

Paul Milenkovic

With respect to railroads having a future, if PTC is this difficult, is self-driving and automatically convoying trucking really "right around the corner" as often claimed?

 

Count me in as a skeptic. I can see where there will be systems to back up drivers, but complete automation in an uncontrolled environment?  Not any time soon.  Deer?  Moose?  Black ice?  Blowing snow?  One truck in convoy blows tire?  Leaks oil?  etc. etc. 

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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