From: jishnu@nospam.verizon.net   
      
   On 2/8/2016 9:04 PM, Clark F Morris wrote:   
   > On Mon, 08 Feb 2016 20:18:21 -0500, Michael Finfer   
   >  wrote:   
   >   
   >> On 2/8/2016 12:24 AM, hancock4@bbs.cpcn.com wrote:   
   >>> On Thursday, December 24, 2015 at 10:09:51 AM UTC-5, Jishnu Mukerji wrote:   
   >>>   
   >>>> Operationally NEC is primarily cab signaled system with ACSES overlay.   
   >>>> They are progressively removing trackside block signals, and just   
   >>>> keeping the trackside Home signals. Specially in high density traffic   
   >>>> areas like between Newark and New York, the blocks are now so short that   
   >>>> having trackside signals would make it very very confusing.   
   >>>   
   >>> FWIW, the block signals at the Levittown, PA, station are still in place   
   >>> and in use.   
   >>>   
   >>> I haven't been to Princeton Jct in a while, so I don't know if the   
   >>> block signals there are still in place.   
   >>>   
   >>> SEPTA has removed some block signals from the Chestnut Hill West (ex PRR)   
   >>> line.  Whether they've been merely moved to a new location or permanently   
   >>> pulled I don't know.   
   >>>   
   >>> CSX has added some block signals to its new dedicated track on the   
   >>> West Trenton line.   
   >>>   
   >>> Has anyone been to the LIRR lately?  Does that still have PRR-style   
   >>> signals?   
   >>>   
   >>> FWIW, the Nov-Dec 2015 DVARP bulletin says the following about Positive   
   >>> Train Control:  "while increasing the margin of safety, PTC takes away   
   >>> some margin for on-time performance. Like other automated safety   
   >>> technology, it isn't as smart as an experienced locomotive engineer,   
   >>> and it sets train braking points well ahead of what's necessary under   
   >>> normal conditions. So trains approach junctions and other speed   
   >>> restricted areas slower than they used to."  (page 8).   
   >>>   
   >>>   
   >>> Another cause of SEPTA's slipping on-time performance   
   >>   
   >> Amtrak is converting the corridor between County and Ham to rule 562.   
   >> The automatic block signals at Princeton Jct. are out of service.  I   
   >> have not been there recently to see if they have been removed.   
   >>   
   >>   
   >> From what I understand, the LIRR intends to change to color light   
   >> signals.  I hardly ever go out there, but I have noticed color light   
   >> signals on the main line east of Woodside.   
   >>   
   >> As for PTC, there's no reason for it to degrade on time performance.   
   >> The schedules will have to be lengthened.  That's something that NJ   
   >> Transit excels at.   
   >   
   > At least on the corridor since NJT and AMTRAK are going from one form   
   > of automatic train stop with cab signals to a more sophisticated form,   
   > why should there be any need for lengthening schedules?  Does anyone   
   > know if in Europe implementation of ERTMS level 2 has degraded line   
   > capacity or required lengthening schedules?   
   >   
   > Clark Morris   
   >   
      
   Actually ACSES allows higher speeds through curves enforced through   
   transponders in tracks, than were enforced by signal aspects. For   
   example the Elizabeth curves are now upto 80/70 on the center tracks   
   from what effectively used to be 45 or so enforced by signal aspect.   
      
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