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Aus loco discussion mailing list
Hello:
I came across the "thread" on ANZ EE locomotive
control system whilst surfing railroad sites, and thought that I might add a few
comments.
In respect of control systems and MU
compatibility, as far as I know, EE more-or-less standardized on air operated
throttles with continuously variable engine speed control from circa 1954,
starting with BR/SR 10203. Before adopting this electropneumatic (EP)
control scheme, EE had used 8 and 10 notch electromagnetic (EM) control systems
with a limited number of fixed engine speeds and automatic load control (torque
regulation) on the top notch or top few notches only.
Nevertheless, EM control systems were used on
some later locomotives, presumably because of individual railroad preferences or
for compatibility with earlier locomotives.
Information on hand indicates that at least the
following EE locomotives, excluding UK domestic models, had EM control
schemes: NZR De (8 notch); NZR Df & Dg (10 notch); SAR 900 (10
notch).
I'm guessing that the QR 1200 most likely had 10 notch EM
control. And the NZR Di surely did for compatibility with the Dg and Df,
although maybe with more engine speeds and with automatic load control on more
notches than was the case for the earlier models. Does anyone have full
details on the Di control system?
And simply because they predated EE's adoption of EP control,
one can assume that both the TGR X and the Egyptian 16 cylinder 1A-D-A1 model
had EM control of some kind.
Of the Australian EE models, I understand that
all of those supplied to QR, MRWA and WAGR had EP control, as did the SAR
800s. No doubt, though, Australian-domiciled readers will be able to
comment definitively on this aspect.
It seems likely that the Kenya 8 and 12 cylinder
models, and the Portugal 1400 and 1800 classes also had EP control, although
I've not seen specific confirmation.
On reference suggests that the Malaysia Class 20
had notched, i.e. EM control. The few photographs I have seen show the
usual EE MU jumper socket, but not the ESCP (engine speed control pipe) that
would indicate EP control. Even scarcer photographs of the derivative
Sudan 12 cylinder model also do not reveal an ESCP, so maybe these were EM as
well. Both these models had vacuum brakes for the locomotive as well as
the train, a feature shared with one or two other EE export models, although
air-on-locomotive/vacuum-on-train was more usual for vacuum-braked
railroads. But the Sudan locomotive also had dynamic brakes, so,
very unusually I think, must have had provision for independent control, or at
least independent release of the locomotive vacuum brake.
Unknown to me are the control schemes for the
Ghana and Nigeria 6 cylinder models (both very much like the NZR De except with
Mk II engines), the Ghana 12 cylinder model, and the Malaysia Class 22/Zaire 8
cylinder model. If the Malaya 22 was MU compatible with the Class 20 (and
I don't know this to be the case), then likely it had EM control.
I don't know why EE stayed with EP control and
110 volt auxiliaries, and did not, for example, adopt the US standard 8 notch,
74 volt EM system. Whatever the technical arguments in favor of each, the
latter was surely the de facto world standard by the 1960s, and it might have
served EE better to adopt it, or at least makes its locomotives compatible with
it. Perhaps, based upon UK operations with lower load factors than say in
the US, there was a perceived need for finer control than 8 notches would
allow. E.g., although the majority of first generation BR diesel-electric
locomotives (from all manufacturers) had EP control, a minority had EM control
with 10, rather than 8 notches.
By the way, although 110 volts was standard for
EE control systems and auxiliaries, some early locomotives were different, such
as LMS/BR 10000/1, at 135 volts, and the NZR De, I think at 90
volts.
Steve Palmano
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