Locotrol revisited.

["< Tell >" <telljb@01.ozemail.com.au>]

I recently received an email from a fella who worked on
the integration of the Locotrol systems on the Dash 8
locomotives after Mt. Newman became BHPIO.  He made the
point that some of the original Mount Newman Alco
Centurys had slow speed loading control known as
"locotrol".

I referred to this in a post to aus.rail a long time
ago after my visits into the Pilbara starting 20 years
ago when the big, smokey, occasional flame belching,
Alco Centurys of Mount Newman Mining under full
throttle moved the worlds heaviest trains and loaded
their massive tonnages under Locotrol at less than one
KAR_LOMATER, Oz speak for Kilometres ...per hour.  
  
I was "flamed", pardon the pun, that locotrol was a mid
train helper system and had nothing to do with slow
speed control.  However he pointed out that the
Locotrol systems including the latest Locotrol have
built in slow speed control integrated with the mid
train control.

*Quote:
These later locomotives have slow speed control
integrated with Locotrol.  This is where there is a low
speed control loop utilizing an analog signal that
allows the locomotives to operate below their normal
minimum speed of perhaps 7-10 KPH.  Ordinarily the
locomotive is controlled by four discrete signals in a
(sort of) binary like control know as A valve through D
valve.  The slow speed control uses an analog voltage
that controls the excitation field current in the
traction motors.  The locotrol equipped remote
locomotives get a voltage command from the lead loco
and report speed back to the lead.  This gives closed
loop fractional KPH speed control over the entire train
without the lead consist have to bear the entire load.
*Unquote:

Point you browser >>
http://www.ge-harris.com/products/locotroldp.html

Hey, you might need this for big M's train sim. :) 

As always. 
..........your aus.rail iconoclast.

----Tell
Alice Springs NT
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