From: cfmpublic@ns.sympatico.ca   
      
   On Thu, 11 Feb 2016 07:21:49 -0800 (PST), rcp27g@gmail.com wrote:   
      
   >On Thursday, 11 February 2016 03:24:33 UTC+1, Stephen Sprunk  wrote:   
   >> On 09-Feb-16 10:49, Jishnu Mukerji wrote:   
   >   
   >> > 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.   
   >>   
   >> 12.5kV means four times as much current as 2x25kV, but if they think   
   >> their decrepit infrastructure can handle the load, c'est la vie.   
   >   
   >As I pointed out elsewhere in the thread, DB (German railways) operate   
   significantly higher power trains (200 mph ICE3 units) under 15 kV 16.7 Hz   
   catenery.   
   >   
   >> Variable-tension and 25Hz are far more pressing problems that can be   
   >> corrected independently, though it'd be wise to do both in a way that   
   >> makes moving to 2x25kV later much easier.   
   >   
   >The constant tension catenery is the biggest impediment to improved   
   performance on the NEC.   
      
   My point was about 12.5 KV at 25 Hz vs. 12.5 Kv at 60 Hz.  If I   
   understand Stephen correctly, with modern equipment the difference in   
   power factor  becomes neglible unlike say 25 - 30 years ago when I   
   first heard about this.   Thus it was about how much power could be   
   transmitted to the train at a given voltage and frequency.   
      
   Clark Morris   
   >   
   >Robin   
      
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