On Wednesday, July 11, 2018 at 4:59:37 PM UTC-4, Clark F Morris wrote:   
   > On Wed, 11 Jul 2018 12:54:08 -0700 (PDT), hancock4@bbs.cpcn.com wrote:   
   >   
   > >There is now a big push to finish installing Positive Train Control   
   > >passenger routes.   
   > >   
   > >But what was wrong with the older technology would that automatically   
   > >stop a train if it passed a red signal or exceeded the speed limit   
   > >(per signal) for a block?   
   > >   
   > >It seems the old system did everything we would want.   
   >   
   > PTC will also enforce temporary speed restrictions and permanent ones.   
   > Most of the ATS systems I have read about only enforce stop signals   
   > where PTC will enforce all signals.  ATS probably would not have   
   > prevented either the Philadelphia crash or the Talgo Dupont crash on   
   > the Port Defiance bypass..  PTC would have.   
      
   According to the Popular Science article, the old ATC did limit   
   trains for overspeed violations, which was used on the LIRR.   
      
   There was no ATC in effect in the Phila accident since the   
   civil engineers did not expect a train to be going fast in   
   that section (for a variety of valid reasons).  Note that   
   the train sped up since it was being stoned, which is dangerous.   
   (I suspect the train engineer panicked when a rock hit his windshield).   
      
   I believe had ATC been in place, the accident would've been   
   prevented.  It was quickly installed.   
      
   I don't know enough about the Talgo crash, but I think ATC   
   would've prevented that as well.   
      
   Note that PATCO uses a version of the old-style ATC to control   
   its high speed trains.  It has more signal aspects, which would   
   be necessarily on a modern railroad   
      
      
   > >Note that this system was installed on the LIRR following several   
   > >bad accidents, and AFAIK, was successful in safety.   
   > >   
   > >Further, PATH is a relatively low speed system and is well   
   > >protected by trip-stops.  Why does it speed expensive PTC?   
   > >   
   > The trip stops and the signaling system in general are probably past   
   > end of useful life and need to be replaced anyway.  The old system may   
   > also be more maintenance intensive.   
      
   Based on the recent Trains magazine article, the modern system,   
   despite being electronic, will probably be maintenance intensive   
   as well.  I frequently see signal maintainers visiting the PTC   
   equipment.   
      
   PATH's trip stops and signals date from the 1960s.  Those things are   
   extremely rugged to endure in heavy-duty service and have a long   
   service life.  I don't know their status now.  But I dare say   
   keeping with that conventional technology, especially on PATH,   
   would be more cost-effective than PTC.  Note that on subways   
   speed control is very easy to implement.   
      
      
      
   > >detailed article describing old system here:   
      
   https://books.google.com/booksid=0SADAAAAMBAJ&lpg=PA2&dq=popular   
   20science%20july%201951&pg=PA50#v=onepage&q&f=false   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)