I.R.W. Independent Rotating Wheels

[Peaky 556]

Mike
Have a look again at my post of 22nd August, where I report the minimum radii for the coning to work.
I'm happy to add any further detail if needed.  I did not consider the fillet radius on the outside of the flange, as I considered it generally small enough not to be of significance.
Sorry must away for household chores!
Regards, Tim

[MikeWilliams]

Thanks Tim.  I was away when this thread started and played catch-up when we returned - clearly I missed that bit.  Apologies.

Seems that gauge widening does make a significant difference, at least in theory, although I accept not enough to solve the problem completely.  As I will shortly be buying a large amount of track this is timely, so does anyone have any negative comments about gauge widening?  Anyone had any problems at all?

Mike

[Peaky 556]

Good question Mike.  The other side of the coin is whether anyone has positively noticed any benefits of gauge widening?  I refer to my earlier suggestion that unless our curves are bigger than about 9m radius, gauge widening does not save us.

I have a lot of second hand GRS track to lay over the next few years, in stages, but I'm not aware if any of it is gauge-widened, if indeed they ever marketed such a refinement?

Regards, Tim

[John Candy]

Tim,

GRS do not supply gauge-widened track.
When chatting to Ted S who advocates gauge-widening (Cliff's track) I questioned why he thought it necessary, when GRS did not.
His comment was that GRS track gauge-widens by itself (lack of rigidity) but I have not tested this theory!

Regards,
John.

[IanT]

Of course this wasn't a problem in the past - the 3-point track gauge that the Society sold for use with it's rail and chairs automatically gave gauge widening on curves - and adjusted it to the curvature too. Pretty sure you organised their manufacture at the time Mike?  :-)

Becomes more of a problem with plastic fixed sleeper/chairs - but CB sells gauge-widened (+1mm) for curves so it would seem sensible to use them.

IRW is an interesting idea but personally I'll stick to fixed wheel axles - but if you think the extra hassle is worthwhile Tim - then sure, why not - go for it.

Regards,

IanT

[cabbage]

When Graham Pearce was here he said that Gauge Widening made his coaches easier to corner -you could feel the difference with your hand he said. As you know all my curves are gauge widened and I have "transitional straights" on some of them. I gauge widen on the inner curve.

regards

ralph

[Doddy]

A treatise on independent wheelsets by Siemens Mobility 

www.mobility.siemens.com/mobility/global/SiteCollectionDocuments/Fen/Frail-solutions/trams-and-light-rail/Favenio_radsatz_einzelradfahrwerke_en.pdf

[cabbage]

Robert, check the URL as I get 401?

Regards

Ralph

[Doddy]

Robert, check the URL as I get 401?

Regards

Ralph

Try it again now that John has kindly altered the %2F messages with /

Bob

[Doddy]

Or this one . . . use the first URL listed

https://www.google.co.uk/search?q=siemens+independent+wheels&ie=utf-8&oe=utf-8&client=firefox-b&gfe_rd=cr&ei=Qg2nWavdCMrv8AeMu5mgCQ

[MikeWilliams]

That's very interesting and takes my mind back to the early 1970s when I was at school and taken to a lecture at the AIMechE about APT-E which demonstrated that stability was improved with no wheel coning at all.  Wonder what happened to that idea?

Mike

[Peaky 556]

Bob, very interesting paper. I've wondered how trams in Nottingham get around incredibly tight curves in standard gauge. For those that haven't read it, in essence what it is saying is that IRW enables the tight curves without scuffing, but another trick is needed to assist with centering the wheelset between the rails.  A reprofiled tyre with a "concave" profile instead of a straight cone causes any wheel flange that gets too near the rail to rise to a disproportionately greater rolling radius and assist in self-centering.

Mike, I think you were ahead of me when you asked about the radius to the flange!  The above trick can be achieved using a large radius leading to the flange, so effectively the wheel coning angle is increasing as the flange approaches the rail.

I'm still wondering what to do with all of my Slater's wheelsets.  The plastic hubs are a bit wee to bore for ballraces.  The fillet radius to the flange is very small.  Only half jokingly I ask if there is any appetite in the society for a new wheel standard?!?  I think I know the answer to that!

Regards, Tim

[cabbage]

Tim,

I would say that you keep your Slaters wheels "as is". If you are that concerned then order some slices bar from GLR and you can produce your own custom wheel. I don't think that we need a new std but it is a useful technique for people with tight curves.

The no cone idea comes from Sir Vincent Raven. It was employed on No. 13 as were quite a few revolutionary ideas for the time. My model has no coning but it is due for a rebuild and may be ground with "colonial wheels" for the drivers to help with leaves and fruit! It already has IRW in the front and rear bogies.

When I started this thread all I expected was a universal "no"... What have I started???

[Peaky 556]

Ralph,
I have five coaches worth of Slater's wheels, so will be using them with some kind of IRW conversion.  I am convinced now, having been very dismissive in the past!

Ralph has shown me a couple of ways of achieving IRW, namely a solid axle with two ballraces set into each wheel; and secondly to cut the axle in half then sleeve it with some close-fitting brass tube.  Are there any other suggestions from anyone please?

Cheers, Tim

[Peaky 556]

Here's a sample of a Slater's wheelset converted to IRW.  I reamed the plastic centre then pressed in one of their own brass axle bushes, trimming off the blind end in the lathe to make the bush flush with the inside hub.  Cut a groove on one axle end and assemble with a tiny circlip. 
This clip is necessary to allow one wheel to "pull" the other to keep it away from crossing noses, etc. 
I've asked Slater's for availability of spare axle bushes but no answer as yet.
19 more to go!
Regards, Tim