Allan Brown <ajbrown@ozemail.com.au> wrote in article
<343B0C26.305@ozemail.com.au>... > David Bromage wrote: > > > > Allan Brown (ajbrown@ozemail.com.au) wrote: > > >It is written that the NSWGR 40 class diesel electrics were a
derivative > > >of the American RSD4/5 units, but suitably altered for local
conditions. > > >Considering that the RSD4/5s had asymmetric bogies with all axles > > >driving, what prompted the change resulting in the 40 class having > > >equdistant A-1-A bogies? Why wasn't a Bo-Bo arrangement used? > > > > The same reason the GM1 was A1A and the original F7 was Bo-Bo, to
reduce > > the axle load. The class 40 weighs 113t for a maximum axle load of 19t. > > On Bo-Bo bogies this would mean an axle load of 28.25t. > > > > Cheers > > David > > Thanks, David. If the dummy centre axle is there to help disperse the > weight, why not put it to work by powering it? I must be thick, or > something! (Terry - stay out of this!!!). > > Allan > >
By powering it you would get more weight again - 2 traction motors, gears
etc. You would probably need a more powerful generator to run the extra
traction motors. The diesel would then need to provide more power to drive
the larger generator. Then you have more weight again, but a more powerful
loco. I don't know much about track standards at the time of introduction
of the 40 class but maybe it couldn't handle the extra weight to go to
Co-Co.
Regards,