Class 700 Bogies

[Class66s]

Hi all,

 

Over the past few weeks I've been thinking about building a class 700 in 4mm, and whilst looking around for prototype drawings, I've been looking at pictures of the bogies. I can see both forms of suspension, the air cushion and the hydraulic(?) attached to the side, however I can't see where a pivot would be installed, which has me questioning most EMU and DMU bogies - I'm assuming they all have something which allows them to pivot, am I missing something?

 

In this picture I can see a pattern inbetween the suspension, is this a mounting point? I did find what is supposedly a top view of it here, which I cannot see anything that resembles somewhere to mount a pivot, but unfortunately I cannot access the article to find their source for this picture. Do the air suspension cushions the bogie to pivot, or is there something I'm not seeing?

 

I have seen the impressive thread of the 3D printed version, but it didn't really answer my question about the real thing, and the thread appears to have gone cold. I've spent a few hours googling around on the subject, but there doesn't appear to be alot of information. If anyone could enlighten me, I'd be grateful.

 

Thanks Mark

 

[seraphim]

In common with most air-bag suspension rolling stock, there is no centre pivot on Class 700. The air bags are fairly soft in shear, which allows the bogie to pivot. I'm not sure how braking forces are transmitted on Class 700 (to avoid the embarrassment of the carbodies carrying on when the brake are applied; I'm guessing via the air bags or via the anti-roll bar assembly. 

 

[Claude_Dreyfus]

Do any of these pictures help?

 

 

[Class66s]

Thanks, those pictures are really useful for bogie details and thank you seraphim for your explanation of the pivot question, now all I have to do is figure out how to use a CAD package. Unless anybody knows anymore of the dimensions, wikipedia seems to note the wheel diameter is between 820 and 760 mm, so I suppose I'll work from those as a reference. Thanks for your quick responses.

 

Mark

[newbryford]

There's a thread somewhere about a 3-D 700 in 4mm.

 

Found it:

https://www.rmweb.co.uk/community/index.php?/topic/125715-siemens-class-700-emu-3d-printscratchbuild/

 

 

Edited March 28, 2020 by newbryford

[jim.snowdon]

18 minutes ago, seraphim said:

In common with most air-bag suspension rolling stock, there is no centre pivot on Class 700. The air bags are fairly soft in shear, which allows the bogie to pivot. I'm not sure how braking forces are transmitted on Class 700 (to avoid the embarrassment of the carbodies carrying on when the brake are applied; I'm guessing via the air bags or via the anti-roll bar assembly. 

 

I would expect there to be a pivot in there somewhere, simply because there does need to be a longitudinal connection between the bogie and carbody to transmit the traction and braking forces. The roll bar is designed to cope with transverse roll only and because the articulation between the bogie and the carbody has to allow for bogie rotation, it can't take longitudinal forces.

 

Jim

[newbryford]

24 minutes ago, jim.snowdon said:

I would expect there to be a pivot in there somewhere, simply because there does need to be a longitudinal connection between the bogie and carbody to transmit the traction and braking forces. The roll bar is designed to cope with transverse roll only and because the articulation between the bogie and the carbody has to allow for bogie rotation, it can't take longitudinal forces.

 

Jim

 

Not a visible pivot on this one.

Scroll about halfway down for the Bombardier Flexx Eco. I believe the arrangement is similar to the Siemens bogies.

https://www.masstransitmag.com/rail/media-gallery/12005283/innotrans-2014

 

The Flexx is fitted under Class 220 Voyager and Class 222 Meridian units

[jim.snowdon]

33 minutes ago, newbryford said:

 

Not a visible pivot on this one.

Scroll about halfway down for the Bombardier Flexx Eco. I believe the arrangement is similar to the Siemens bogies.

https://www.masstransitmag.com/rail/media-gallery/12005283/innotrans-2014

 

The Flexx is fitted under Class 220 Voyager and Class 222 Meridian units

That's because what you see on top of the bogie is the bolster that is bolted solidly to the bottom of the car body. The bogie pivots underneath that, and there will be a pivot pin in there, buried inside the bogie frame.

 

Jim

[seraphim]

There are further pictures here: http://extra.southernelectric.org.uk/news/tsgn/2014-class700-interiors-mockup-4.html

 

I share Jim Snowdon's surprise that there is no apparent traction rod or similar for transmitting traction or braking forces, but it seems not. Must all be done through the airbags, I guess.

 

[newbryford]

1 hour ago, jim.snowdon said:

That's because what you see on top of the bogie is the bolster that is bolted solidly to the bottom of the car body. The bogie pivots underneath that, and there will be a pivot pin in there, buried inside the bogie frame.

 

Jim

 

I see the bolster in the upper photo, but have a look at the photo below it.

That must be one heck of a length of a pivot pin from the bolster or vehicle body - if there is one.

 

No visible pivot pin on page 13 or 14 of this:

http://www.dmg-berlin.info/page/downloads/vortrag_koebel.pdf

 

Pivot pin location on bogie? (Siemens SF7000 which is fitted to the 700s)

https://www.railwaygazette.com/uk/siemens-lincoln-bogie-service-centre-obtains-risas-certification/47494.article

 

Precursor to the SF7000 is the SF5000, fitted to the likes of 350s etc.

No pivot point, but it does have a traction rod. (Pic snipped from a Siemens webpage)

 

Edited March 28, 2020 by newbryford

[jim.snowdon]

Good pictures. For the SF7000, the bogie does have an aperture to take a pivot pin, and yes, the pin will be quit substantial. Things have moved on a long way from the traditional centre pin and bowl bearing of typical steam era bogies.

 

 The SF5000 is interesting as it is a true centreless bogie, relying only on the stiffness in the secondary suspension and the bushes in the traction rod to control its transverse motion. There is, I suspect, a bit more to it than that and some knowledge of just what is under the car body would be useful in completing the picture.

 

Jim

[newbryford]

The SF7000 was developed as a lighter weight version of the SF5000, so I doubt there would be a regression to a centre pivot. Hopefully someone that works on the 700s can give a definitive answer.

 

Anyway - back on topic.

The model version will most likely have to have a centre pivot if only for the sharper radius curves that we use.

[5944]

I'll have a look at a 717 tomorrow and try and get a photo of the centre of a bogie. And yes, 820mm for full size wheels. 

[Class66s]

Hi all,

 

thank you for your responses, whilst looking for more information I found a couple of papers about on research gate, but I've had trouble with their website, and am not sure if it worked when I requested the full text for them: https://www.researchgate.net/publication/298444070_SF7000_-_Innovative_Bogie_concept_in_answer_to_Whole_Life_Cost_models

 

If it turns out the full scale unit transfers the forces through the air cushion, I had thought of a potential way of going without a centre pin, by cutting slots in the top of the model cushion, to allow it to rotate on these. There would then be some sort of pin to lock the bogie into the slot, perhaps a small screw into the bottom of the carriage body on each side. When we know more and I've finished my coursework I'll try and do a more comprehensive drawing, but attached is the basic concept, I have no idea how well it would work!

 

Though whilst looking through google images, I found this side on view, which shows a rectangular sort of slot, which would make sense to be for a bogie pin.

 

Mark

 

[The Stationmaster]

Pivotless bogies have been around for a very long time.  William Dean used them on his big singles (and i think a coach bogie design) and a German, Krauss Maffei, design of pivotless bogie was used on the D8XX and D10XX diesel hydraulics.  However the German design was found to cause problems with lateral acceleration of the loco body and both of the diesel hydraulic classes were limited to 60mph pending a solution.  The Swindon solution was to revise the design and instead use the lateral control arrangement Dean had used in  his pivotless bogie - this solved the problem and the modified locos were then permitted to run at maximum design speed. 

[jim.snowdon]

1 hour ago, The Stationmaster said:

Pivotless bogies have been around for a very long time.  William Dean used them on his big singles (and i think a coach bogie design) and a German, Krauss Maffei, design of pivotless bogie was used on the D8XX and D10XX diesel hydraulics.  However the German design was found to cause problems with lateral acceleration of the loco body and both of the diesel hydraulic classes were limited to 60mph pending a solution.  The Swindon solution was to revise the design and instead use the lateral control arrangement Dean had used in  his pivotless bogie - this solved the problem and the modified locos were then permitted to run at maximum design speed. 

However, the Dean carriage bogie did have a pivot, although it wasn't in a sleeve bearing as such, merely contained within a box in the bogie frame. I think the locomotive bogies were the same, but I haven't got the book to hand.

 

One of Dean's odder designs was a 4-2-4T with pendulum link bogies both ends, and flangeless driving wheels as well. Its ability to remain on the rails was, roundly, nil, essentially due to a total lack of positive guidance.

 

Jim

[5944]

Yes, the rectangular slot is for the bogie pivot. It's a sort of curved, pyramid shape. Can't get a decent photo of one, the bogies are pretty cramped, sorry. 

[jim.snowdon]

5 hours ago, The Stationmaster said:

Pivotless bogies have been around for a very long time.  William Dean used them on his big singles (and i think a coach bogie design) and a German, Krauss Maffei, design of pivotless bogie was used on the D8XX and D10XX diesel hydraulics.

Now found the book. The Dean locomotive bogie, as on the Singles and the 4-4-0s, did have a centre pin (and side control springs acting directly on it).

 

Jim

[The Stationmaster]

18 hours ago, jim.snowdon said:

Now found the book. The Dean locomotive bogie, as on the Singles and the 4-4-0s, did have a centre pin (and side control springs acting directly on it).

 

Jim

The diesel hydraulics definitely didn't tho'   (because they had part of the transmission on the way)

[5944]

 

The centre pivot is just visible behind the air bag on the bogie. You can see it on the drawing too, top line, second drawing in from the left. 

[Class66s]

Hi 5944,

 

Thank you for the useful picture showing the bogie pivot, does anyone know if the wheel set was  near new (800mm) in this picture, so I can use it in combination with others as a reference?