From: stephen@sprunk.org   
      
   On 11-Jan-16 00:50, Michael Moroney wrote:   
   > Stephen Sprunk  writes:   
   >> On 10-Jan-16 12:36, hancock4@bbs.cpcn.com wrote:   
   >>> Stephen Sprunk wrote:   
   >>>> One of the things that's frustrating about Amtrak is that they   
   >>>> tie numerous projects together into one mega-project, then   
   >>>> complain they don't have the funding and do nothing, whereas   
   >>>> they _do_ have funding for one project at a time, and its   
   >>>> benefits would fund the rest.   
   >>>   
   >>> Could you elaborate on some examples of the above?  Thanks.   
   >   
   >> The first that comes to mind is constant-tension catenary,   
   >> switching to 2x25kV, switching to 60Hz, and upgrading to 150mph+.   
   >> Any of those could be done independently, and at least two of them   
   >> would save enough money to pay for the other(s) later.   
   >   
   >> The result is that most of Amtrak's trackage is still on   
   >> variable-tension at 11kV 25Hz at 125/135mph, aside from the   
   >> newly-electrified section in RI/MA and (recently) one short section   
   >> in NJ.  In contrast, MNRR long ago upgraded their trackage to   
   >> constant-tension at 2x12.5kV 60Hz, so it's not like Amtrak could   
   >> think it's impossible.   
   >   
   > They really aren't completely independent.  Converting to 2x25kV as   
   > the first step would require 25kV 25Hz transformers and equipment,   
   > only to be replaced by 60Hz on the next step.  If combined, one   
   > entire set of equipment could be skipped.   
      
   25Hz transformers can handle 60Hz.  It'd be simplest to go to 12.5kV   
   60Hz first, which wouldn't require _any_ new equipment, a few phase   
   breaks at most.  (That assumes all 25Hz-oly wayside equipment has been   
   replaced with 25/60Hz equipment, which Amtrak has been doing as the   
   former fails since at least the 1980s.)   
      
   That would allow dismantling the 25Hz distribution network and pesky   
   frequency converters--and saving money on maintenance plus selling off   
   an enormous amount of scrap metal.  That would pay for the above plus,   
   most likely, the new transformers, autotransformers and feeder lines   
   you'd need to go to 2x12.5kV instead.   
      
   Going from 2x12.5kV to 2x25kV, if you planned ahead, is trivial; just   
   change taps on the transformers.  But that can wait until the catenary   
   is replaced--which _is_ a completely independent project--and any   
   non-voltage-agile equipment is retired.   
      
   > Also, going to constant tension with insulators good for only 12.5kV   
   > would be a waste of money.   
      
   Obviously, if you're going to replace the catenary, you'd insulate for   
   25kV even if you're only going to 12.5kV today; that's what NJT did   
   until they retired the last of their non-voltage-agile equipment.   
      
   > Where is the recent 25kV 25Hz section?   
      
   The recently upgraded section in NJ is New Brunswick to Trenton; it's   
   160mph, so it _must_ have constant-tension catenary, and unless Amtrak   
   were idiots, the insulators should be ready for 25kV.  I don't know if   
   they actually switched the power to 25kV and/or 60Hz; if not, they're   
   finally breaking from their dogma of the last 30+ years.   
      
   S   
      
   --   
   Stephen Sprunk         "God does not play dice."  --Albert Einstein   
   CCIE #3723         "God is an inveterate gambler, and He throws the   
   K5SSS        dice at every possible opportunity." --Stephen Hawking   
      
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