From: rcp27g@gmail.com   
      
   Clark F Morris  wrote:   
   > 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.   
      
   Right, but there are plenty of examples of high power locomotives on the   
   Swiss/German/Austrian 15 kV 16.7 Hz networks that cope with low frequency   
   and not much higher voltage. Going back to the days before power   
   electronics, for example the Swiss Ae 6/6 were built starting in 1955 and   
   are rated at 4.3 MW which is within the range of modern high speed train   
   power cars. Modern European locomotives are all designed to run on the main   
   four systems of 25 kV 50 Hz, 15 kV 16.7 Hz, 3 kV DC and 1500 V DC. While   
   they sometimes have a lower power output on DC, there is no problem with   
   the low frequency system.   
      
   Robin   
      
   --- SoupGate/W32 v1.03   
    * Origin: LiveWire BBS -=*=- UseNet FTN Gateway (1:2320/1)