Loco with offset axles

[themickster.mg]

There is a diesel Co-Co with the middle axle offset to one end of the bogie. Was it class 59? I'm trying to find out why that axle was offset.

 

[37057]

Class 56 - I don't have the answer as to why but possibly for traction motor clearance.

 

[hwl]

There is a diesel Co-Co with the middle axle offset to one end of the bogie. Was it class 59? I'm trying to find out why that axle was offset.

Steerable EMD bogies have asymmetric axle spacing 80" & 84"

 

[rebmcr]

There was also the Co-Bo Class 28.

 

[themickster.mg]

Thank you.

 

[hexagon789]

There is a diesel Co-Co with the middle axle offset to one end of the bogie. Was it class 59? I'm trying to find out why that axle was offset.

Many General Motors locos are the same, certainly the Irish 071 and 201 Co-Co locos are arranged thus.

 

[Kneedown]

I'm not sure if the class 56 had offset axles. I don't believe so (although stand to be corrected) but i'm pretty sure the 58 did.

 

[hexagon789]

I'm not sure if the class 56 had offset axles. I don't believe so (although stand to be corrected) but i'm pretty sure the 58 did.

They do it seems (spacing of 1950mm between the outer pair and 2150mm between the centre and inner axle). All of 56, 58 and 59 have offset axles at different spacings going off the relevant pages from the diagram books:

 

[Wyrleybart]

On the contrary, I think locos with symmetrical axle spacing are in the minority, certainly indigenous classes. Perhaps the "Co" bogie under 37 50 and 50 is an exception.

 

[hexagon789]

On the contrary, I think locos with symmetrical axle spacing are in the minority, certainly indigenous classes. Perhaps the "Co" bogie under 37 50 and 50 is an exception.

The bogie design of 37s is shared with that of 50s/55s, all are identical, equally spaced 6' 9" (2057mm).

 

[hwl]

and 59 have offset axles at different spacings going off the relevant pages from the diagram books:



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As I said above steerable EMD 3 axle bogies have asymmetric axle spacing 80" & 84" e.g. 59, 66, and the 201s have asymmetric axle spacing.

 

[Richard Scott]

This got me thinking about the 1Co-Co1locos. The powered axles look to be the same distance apart but the pony truck is closer to the first powered axle. I'm guessing spring rates allowed fairly even axle load on each powered axle with less on the pony truck? Does anyone have any info on axle loadings for each axle on a 40, 44, 45 or 46? Any info appreciated.

 

[Kneedown]

They do it seems (spacing of 1950mm between the outer pair and 2150mm between the centre and inner axle). All of 56, 58 and 59 have offset axles at different spacings going off the relevant pages from the diagram books:

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Well everyday is a school day. Drove 56's and 58's for years and only ever noticed the odd spacing on the 58's!

 

[pdeaves]

This got me thinking about the 1Co-Co1locos. The powered axles look to be the same distance apart but the pony truck is closer to the first powered axle. I'm guessing spring rates allowed fairly even axle load on each powered axle with less on the pony truck? Does anyone have any info on axle loadings for each axle on a 40, 44, 45 or 46? Any info appreciated.

I don't know about loadings but there may be a simple geometrical reason why the pony wheel is closer: if it is smaller there is physically the space available to move the centre point inwards a bit, reducing overall length and consequently making curves that bit less difficult.

 

[themickster.mg]

There was a class with a markedly offset middle axle. I think it was the 59.

 

[PaulLothian]

It was common in steam days for the distances between a locomotive's coupled axles to vary, for a variety of engineering reasons. I would have assumed the same applied to diesels.

 

[hwl]

There was a class with a markedly offset middle axle. I think it was the 59.

The offset on the 59s is 4" does that qualify as markedly for you?

 

[ac6000cw]

As I said above steerable EMD 3 axle bogies have asymmetric axle spacing 80" & 84" e.g. 59, 66, and the 201s have asymmetric axle spacing.

Don't the 59's (and the Irish 201's) have non-steerable bogies e.g. 'export' HTC on the 59, versus 'export' HTCR (radial steerable) on the 66's?

I agree that both the steerable and non-steerable HTC bogies have unequal axle spacing.

 

[hexagon789]

Well everyday is a school day. Drove 56's and 58's for years and only ever noticed the odd spacing on the 58's!

Not just yourself, I thought they were equal on 56s as well, but I decided I'd better check just in case!

 

[hexagon789]

As I said above steerable EMD 3 axle bogies have asymmetric axle spacing 80" & 84" e.g. 59, 66, and the 201s have asymmetric axle spacing.

I knew 66s have radial bogies but didn't know about 59s. IÉ 071s aren't radials afaik but are unevenly spaced

 

[Dunfanaghy Rd]

Somewhere at home a book that I can't find (!) has a section on 'Trucks' (as they term them). It makes a point about 1 design as having equal spacing ( GM Flexicoil, I think) because it was a first. I'll take a guess that it is all to do with fitting 3 traction motors around the pivot.
The GC bogie as seen on 071 and 201 classes on IÉ are a GM export standard, and can be seen all over - Spain, Serbia, North Africa, take your pick. Unusually they were used on 1 US class - SDL39 built for the Milwaukee Road and ending up on Wisconsin Central. (Very nice they looked, to.)
Pat

 

[37201xoIM]

Very common on ALCo 3-axle (i.e. Co-Co) locos' bogies, e.g. https://www.flickr.com/photos/abhinavnfr/8032803768 (not my phot BTW!)

I believe it's related to the way the traction-motors (nose-suspended?) face?

 

[ac6000cw]

Somewhere at home a book that I can't find (!) has a section on 'Trucks' (as they term them). It makes a point about 1 design as having equal spacing ( GM Flexicoil, I think) because it was a first. I'll take a guess that it is all to do with fitting 3 traction motors around the pivot.
The GC bogie as seen on 071 and 201 classes on IÉ are a GM export standard, and can be seen all over - Spain, Serbia, North Africa, take your pick. Unusually they were used on 1 US class - SDL39 built for the Milwaukee Road and ending up on Wisconsin Central. (Very nice they looked, to.)
Pat

There is a design paper on the development of the EMD HT-C bogie here - https://utahrails.net/loconotes/EMD_HTC-Truck_ASME_72-RT-3_March-1972.pdf - Fig.5 is a comparison diagram of the layouts of the axles and motors between the HT-C and a 'conventional' bogie (probably the EMD Flexicoil, but it doesn't actually say).

 

[themickster.mg]

Thank you. It was 59 I was thinking about. Motor fitting works for me as an answer.

 

[delt1c]

OK a shunter but for me the most noticeable offset was the LMS 12003 - 12032 which a very large space between the centre wheels and the wheels underneath the cab. This was for the Jack shaft

 

[themickster.mg]

Delt1c, was that shunter the same as the D3/7? That had a jack shaft between the two rearmost axles.

 

[37201xoIM]

To be fair, isn't that self-evident for anything with three axles on the frame or bogie and an intermediate jackshaft? Take a look at a crocodile!

 

[Rob F]

This got me thinking about the 1Co-Co1locos. The powered axles look to be the same distance apart but the pony truck is closer to the first powered axle. I'm guessing spring rates allowed fairly even axle load on each powered axle with less on the pony truck? Does anyone have any info on axle loadings for each axle on a 40, 44, 45 or 46? Any info appreciated.

Don’t have the numbers but I am sure I remember reading that EE did a better job on the 1Co bogie under the 40s than BR did with the Peaks, having an equal axle load on each of the driven axles. This was why the 40s had a lower Route Availability.

 

[Richard Scott]

Don’t have the numbers but I am sure I remember reading that EE did a better job on the 1Co bogie under the 40s than BR did with the Peaks, having an equal axle load on each of the driven axles. This was why the 40s had a lower Route Availability.

Would be interesting to know actual axle loads. To be fair 40s were slightly lighter than the peaks. When fitted with ETH the 45/1s shed 3 tons and think it was enough to reduce RA to 6 from 7? As always happy to be corrected.