From: cfmpublic@ns.sympatico.ca   
      
   On Wed, 13 Jan 2016 22:48:02 -0600, Stephen Sprunk   
    wrote:   
      
   >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.)   
      
   Except as I understand it, 12.5 KV won't give enough power to support   
   100+ mile an hour operation.  Note the relatively slow speeds on the   
   Metro-North New Haven line.   
      
   Clark Morris   
   >   
   >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   
      
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