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Aus loco discussion mailing list
Greetings
Perhaps now might be a good time to explain how the GM's were
coupled to the EE and Mitsubishi locos for MU operation.
In 1979 the then NZR purchased 20 General Motors GL22MC type
locomotives. They were classed DF with road numbers 1651-1670. The
first 10 went to the North Island and the second 10 to the South. They
were delivered from GM in Canada fitted with twin jumper sockets at each end of
the loco, the first being the standard jumper for use with the other GM (Da, Db,
Dc and Dbr classes) and GE (Dx class) locos of the day. The second socket
was for MU operation with the English Electric Dg and Di class and the
Mitsubishi Dj class of which both were found solely in the South Island.
There were 5 Di, 62 Dj and 38 Dg class in service at the time.
It was just a matter of plugging in the correct jumper in the
correct socket and away you went.
There was a problem with the air supply as the EE/Mitsi locos
were 4 pipe (BP, MR, EP and ER) and the GMs were 3 pipe (BP, MR and EP).
The Df were fitted with 4 pipes on the headstock. When coupling to another
3 pipe then the MU2A had to be set to trail 3 pipe and when coupled to a 4 pipe
then it was set to trail 4 pipe. Every thing else was set up as
normal.
Dj and Di class were fitted with 26L brakes but the Dg was
fitted with 6SL brakes (the 10 rebuild Dg's were fitted with a push button
"push and pray" or "hit and hope" brake but don't know of
the classification).
We got some of the second series Df class which were purchased
in 1983 here in the south Island aswell. these were not fitted for MU
operation with EE/Mitsi locos and only had 3 pipe brake system. If the Dj class
or the Toshiba electrics from Otira were towed they had a weird arrangement of
coupling the BP-BP, MR-MR and EP-ER if I remember correctly.
I'm not entirely sure how it worked and I maybe wrong but I seem to remember that when N1 was selected in the Df then the Dg or Dj went straight to N2 (with the subsequent shove from behind!). Somewhere along the lines another notch on the Dj/Dg was missed but I have no idea which one. None of the books I have tell me which one it was. I worked a number of trains with combinations of Df/Dj as a
fireman and remember them as not being overly successfull. Unfortunately the Dg
class had by 1985 been retired from service.
As far as I know these combinations were always Df leading
with either one or two locos in trail. I can't remember any times were
there was a EE or Mitsi in the lead of a Df but it might have occasionally
occured if it was indeed possible. Presumably if the GM could control the
EE then it would be possible in reverse.
It was possible to MU other GM or GE locos with a Df and have
the EE or Mitsi trailing the Df, which may have been trialed but as there were
no other GM or GE's in the South Island and the Dg and Dj only ventured north on
very rare occasions it is unlikely.
I don't recall ever hearing of a Df/Di combination (Di locos
were captive in the Dunedin area for use on suburban passenger services and only
ventured north to Christchurch for wheel lathe attention).
I have my old Loco Staff operating Instruction book here with
all the brake diagrams etc so if anyone wants copies of this stuff let me know
and I will either photocopy it and send it or scan it.
Cheers
John
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