CR/AN NSU & NT: MU

["Steve Palmano" <steve719@GTE.net>]

Aus loco discussion mailing list

Hello All:

Ben Scaro commented: "In the small book, 'Rails to the Top End', there are
photos of an NJ
coupled back to back with an NT on a train- the 'Chaser' which followed the
Ghan,
I think.  I'd always assumed from this that NJs might have had the ability
to work with NTs- but the combo probably occurred due to a breakdown or loco
balancing requirements."

This comment about the NT/NJ combination triggered a vague memory, and sent
me looking through my library.  Leon Oberg's book "Motive Power", on page
53, has a picture of NJ5 back-to-back with NT74.  The caption does not
indicate whether both are working, or that the NT is dead.  Without giving
it much thought I must admit, I had always assumed the latter.  Just maybe,
the NJs were equipped to MU with the Sulzers...?

Also, further digging has led me to deduce that the NSUs and NTs had a
control scheme with a continuously variable, air operated throttle, i.e. EP.

To quote from the reference, which was talking about BR locomotive
development, "...EE had evolved a pneumatic speed control for BR locomotive
10203, while Sulzer had developed a similar system in Switzerland which had
been used on locomotives built by BRCW exported from the UK."

Now, as far as I know, BRCW exported only three batches of Sulzer-engined
locomotives, namely the CR NSUs, 5 similar locomotives for the Sierra Leone
Development Company (SLDC), both of which had CP/AW electrical equipment,
and 12 for CIE that had MV electrical equipment (and almost certainly 10
notch EM control).  Ergo, the NSUs and the SLDC counterparts had EP control.
And logically, so did the NTs for compatibility with the NSUs.

If indeed the NJs could MU with the NTs and NSUs, matching the standard
American 8 notch EM control system to the EP system would be a slightly
different proposition to the NZR GM/EE scheme, but seemingly not infeasible.
After all, EM8 to EP conversion was done in the QR Locotrol system;
presumably each of the 8 notches maps to an appropriate value of throttle
line pressure in the EP system.  EP back to EM is a bit like
analog-to-digital conversion, maybe with some hysteresis to prevent hunting.

It could be, though, that brake piping and jumper cable wiring allowing,
that the NSUs and NTs would have been able to MU with say the QR EEs, or
those WAGR EEs equipped with air train brakes.

Anyway, the above leaves two issues for further comment from anyone who
knows:

    Confirmation that the NSUs and NTs had EP control; and:

    Could the NJs MU with the NSUs and NTs?

Cheers,

Steve Palmano


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