Australian Tri-Bo locomotive.
 

Until Steve mentioned it on a gallery comment I'd never heard of Tri-Bo locomotives.

Some photos.

https://www.ardp.net/topic66.html

Plenty of "Tri-Bo's" in Switzerland. Known as Re6/6.

https://www.railwayforum.net/gallery...r&imageuser=40

Closer to home the Channel Tunnel shuttle locos are also Tri-Bo.

The Tri-Bo is mostly a narrow gauge contraption.
A number were built for Japan and also Kiwiland for the 3 foot 6 inch.
The advantage of a tri-bo over a standard Co-Co being that flange wear should be reduced.
The middle bogie is normally floating.
The QR electric locos are tri-bos, again for 3 foot six inch.
With almost constant curves on the NSW Blue Mountains, it was believed that the tri-bo design would provide for less flange wear and wheel creep.
But, I can attest that 8650 did yaw and sway all over the place.
Quick give me the sea sick pills.
It was never adjudicated as to whether the tri-bo design performed any better.
Sadly, as with most of our once magnificent electric loco fleet, 8650 is shoved out at Broken Hill rusting to the rails.
Steve.

Just uploaded a photo of 8650 at LMC Lithgow in 1990.
The only tri-bo on the NSWR.https://www.railwayforum.net/gallery...1_dec_1990.jpg

Hi Steve, with the Tri-Bo having a floating middle bogie did this improve their adhesion?

G'day Master,
A Bo-Bo will get up and go a tad quicker than a Co-Co, and be able to provide higher speed depending upon wheel diameter and gearing.
Naturally two less traction motors sharing the voltage etc.
Hence many pas weasels or buzz boxes were / are Bo-Bos.
But, to slog it out on steep grades with heavier loads, the Co-Co has more ability.
Naturally all units can wheel-slip, but a high wheeler Bo-Bo will suffer more wheel slip potential than a smaller wheel diameter Co-Co.
8650 being a Tri-Bo did not manage to lift heavy loads with any more agility to the standard Co-Cos.
But, it was supposed to cause less flange and rail head wear.
Additional loco weight was not possible due to our rail axle weight ratios.
I guess similar to the Beyer Garratt soot belcher concept which did NOT provide double the oomph of the normal pair of equivalents.
It was sad that one aspect of 8650 was not further envisaged.
It had the ability to be converted to 25 kVA.
Our woeful 1500 vDC system just could not hack the additional oomph necessary for quad multiple buzz box loads.
Steve.

Cheers Steve, appreciated.