Backshophoss wrote: ↑Wed Nov 13, 2019 5:39 pm
The ex-PRR grid is very extensive,and not easy to upgrade,Amtrak has invested in the 25hz grid and generation of power.
Unlike the DL&W(NJT)and MN upgrades,this is a costly undertaking,way too many overpasses/bridges to replace for proper air gaps
at the higher voltage,even a 12.5 kv 60hz.
While an antique system,this is still a functional system that has held up well over time
Believe you are making some unfounded assumptions. Yes Amtrak has invested in the 25 Hz grid but all CAT investments are dual frequency compatible. Transformers, Breakers, signal power, etc. However some station equipment mainly motors are still 25 Hz but have slowly been converted to public power 60 Hz, 60 Hz motors much less bulky.. However signals are a problem as much of it will not work with 60 Hz power. However as Amtrak has upgraded signal systems at various locations it has converted the signals to 91-1/3HZ ( not sure of freq ).
You forget that the 25Hz of Amtrak is already at 12Kv nominal +/- 10 % All clearance as far as I can tell were planned when Amtrak went from 11.5 Kv to 12.
One problem with the CAT transmission lines is that they are single phase not 3 phase That is it mirrors your home power as 69Kv to ground and the other line 180 degrees to be - 69 Kv. That gives the 138 Kv phase to phase. A transition would cause commercial power to convert from 3 phase to single phase but understand it can be completed.