From: jishnu@nospam.verizon.net   
      
   On 1/15/2016 2:26 PM, Stephen Sprunk wrote:   
   > On 14-Jan-16 17:10, Clark F Morris wrote:   
   >> Stephen Sprunk  wrote:   
   >>> On 11-Jan-16 00:50, Michael Moroney wrote:   
   >>>> 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.   
   >   
   > Amtrak (and its predecessors) have been doing up to 135mph on 11kV 25Hz   
   > lines for around a century; the main reason they couldn't go faster was   
   > the variable-tension catenary.  That's roughly twice as much current as   
   > 200mph on 2x25kV lines in France and China, so I'm not sure current is   
   > really a limiting factor.   
   >   
   > S   
      
   125mph operations began in the late 60's as part of the NECIP. Before   
   that the highest anyone might have gone is 100mph or so. So no, no one   
   has been operating at upto 135mph for a century. Just 50 something years   
   at 125mph.   
      
   MNRR is yet to complete their conversion to Constant Tension catenary.   
   About 80% of the project is done with 20% remaining. They did convert to   
   60Hz quite a while back.   
      
   Amtrak is neither changing the voltage nor the frequency on NEC south.   
   They are adding 25Hz capacity. They don't foresee any problem with   
   operating at 160mph using 12.5kV 25Hz.   
      
   Also BTW, Amtrak's conversion to position light does not remove the   
   middle lamp. Effectively just replaces the lamps with color LED. In   
   addition additional logic is added for additional flashing aspects. The   
   old signal heads do not have the logic to display flashing aspects.   
      
   TAFN   
      
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