International Railroad Discussion > New Zealand locomotive question

When I was in New Zealand recently I came across a locomotive wheel arrangement with which I'm not familiar.  I've attached pictures to help me ask my questions.  So far as I can tell the locomotive (which I think may be Chinese) has six axles that are spread pretty equally under its body, rather than being at the ends, as is more normal and which I saw on other Kiwi Rail locomotives in freight service.  It appears that they may be in three two-axle trucks, but that was not clear from my limited observation.  I'd like to know exactly what this arrangement is (B-B-B?) and what its purpose is.  Is it important to spread the locomotive's weight equally over its body?  Does the fact that the New Zealand gauge is 3' 6" have anything to do with this (as I understand it the New Zealand rails are built to a fairly high standard for a narrow gauge)?  Does it make it possible  to run at a higher speed than otherwise?  Is this common for New Zealand locomotives?  This locomotive was on a tourist train leaving the Dunedin station; is there something about passenger trains that encourages this arrangement?  In any case, I'd appreciate any information you can give.

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The Locomotives are Class DJ built by Mitsubishi Heavy Industries in Japan in 1967 - 1968. Originally there were 64 built. The Bo - Bo - Bo wheel arrangement was to keep axle loadings down, but offering better tracking on curves. The diesel engine used was a Cat D398.

Thanks for the response.

The EF class electrics (on the North Island) have the same wheel arrangements.   Built in the UK by Brush.

In Japan there are some Bo-Bo-Bo electric locos e.g Class EF200.

The channel tunnel (UK-France) has a fleet of Bo-Bo-Bo electric locomotives; this wheel arrangement gives the same axle loadings as a Co-Co but with the ability to negotiate tighter track curvature without encountering problems.

B-B-B (or UIC Bo'Bo'Bo') https://en.wikipedia.org/wiki/Bo-Bo-Bo

New Zealand, EW and EF electrics
Australia (Queensland), there were around 200 electrics, in several classes
Bolivia, 2 different classes of diesel from Japanese builders
Ecuador, Alstom diesels
Burma (Myanmar), diesels from both European and Chinese builders
China, electrics
Japan, electrics, also several classes of diesel
Korea, 8000 Class Electric, derivative of Alstom European type
Plus European countries listed in Wikipedia above

Only one EMD GM10B was built.  Here it is at the EMD plant, McCook, Illinois, 7/9/76.

See also:

https://en.wikipedia.org/wiki/EMD_GM10B

Gerry

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When the DJ class were introduced, many of the New Zealand branch lines that existed at the time were lightly laid with jointed rail on tight curves. The trucks with two axles each were easier on tightly curving track because of their short wheelbase, rather than the longer wheelbase of a rigid three axle truck in the days before modern radial/steering trucks. 

The middle bogie/truck has to move from side to side on curves, so can't sit in a pivot, but also needs to transfer its power to the loco frame. On modern Bo-Bo-Bo locos, the three trucks are usually physically connected together. On that Mitsubishi DJ, there was actually a 'pole' that extended down from the frame to mate with a slot arrangement in the bogie which allowed for side-to-side movement. The DJ coil springs were attached between truck and loco frame on the front and rear truck, but strangely had a complicated arrangement with rollers on top of the middle springs that could slide across a channel under the frame for weight transfer. 

In Switzerland, the Re 6/6 loco of the same era was also designed with three two-axle trucks, replacing the co-co Ae 6/6 which they called 'The Track Killer" on the Gotthard Pass. Still in service, the Re 6/6 is a fascinating machine - a straight electric and has an axle load twice that of the DJ, but manages to put down 10,700 horsepower. The DJ's Caterpilller engine puts out a little over a thousand!

Not at all uncommon in Myanmar either.

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Only a moma could love that EMD in that paint.

This is a B-B-B in Ecuador

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CRRC recently delivered additional B-B-B locos to Myanmar

http://p1.pstatp.com/large/8606/1430261286

Initially supplied by CSR Qishuyan, CKD6 and CKD7, basically similar shells, different MTU prime movers
http://www.qscn.com/english/products.asp?Action=Detail&ID=136

Later batches from CNR Dalian, CKD7 and CKD7B, both Cat 3516
http://www.dloco.com/LISTS/product/_MAINPAGE/EProducts/default3.aspx?id=1118

Last deliveries appear to be in Q4 2015
http://www.railwaygazette.com/news/traction-rolling-stock/single-view/view/myanmar-diesel-locomotive-deliveries.html?sword_list=Myanmar&no_cache=1

It is hard to track Chinese rail exports into Myanmar, as the loco orders were placed by the Myanmar Government with Chinese middlemen, both Yunnan Machinery & Equipment Export & Import Co. Ltd., and Union Resources & Engineering Co. Ltd. have been involved (20 locos each). In turn these middlemen subcontract the assembly to the various state owned shops.
All of the "companies" in the chain appear to be majority owned by the State-owned Assets Supervision and Administration Commission of the State Council (ie under direct Party control)
From loco numbers sighted in image searches, probably at least 80 units have been supplied
 

86235 Wrote:
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> This is a B-B-B in Ecuador


Why is everyone riding up top?

chakk Wrote:
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> 86235 Wrote:
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> > This is a B-B-B in Ecuador
>
>
> Why is everyone riding up top?

Only the tourists are riding on top, the few locals are in the passenger car on the rear of the boxcars. Back in 2006 you rode the train on the roof down the Devil's Nose.