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Rimless wheels

This topic has 18 replies, 7 voices, and was last updated 26 August 2010 at 18:50 by Ian Abbott.

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19 August 2010 at 05:32 #54420
Sam Stones
Participant
@samstones42903
Here’s one for you railway enthusiasts.

Many years ago (before 1972), I recall seeing on British TV, a system for steering the bogies on full size railway rolling-stock, such that the wheel flanges never touched the sides of the rails.

A camera positioned close to the wheel/rail actually showed this to be the case. There was even a suggestion that the design was so good, flanges could be removed. Not that you would really chance that, would you?.

The Curator of Railways, National Railway Museum, York was unable to help. I’m not even sure if my story was fully understood.

Does anyone know what happened to this clever design?

Sam

Edited By Sam Stones on 19/08/2010 05:32:58
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19 August 2010 at 05:32 #21719
Sam Stones
Participant
@samstones42903
What ever happened to . . .
19 August 2010 at 08:43 #54421
KWIL
Participant
@kwil
ME Vol 190 carried a series by D Hudson on self steering bogies, perhaps there is a reference there?
19 August 2010 at 09:06 #54422
Brian Oldford
Participant
@brianoldford70365
Answering what I think is your question.

The reality is, on a correctly profiled wheel, the flanges rarely touch the rails. The wheelset is guided primarily by the tyre coning.
19 August 2010 at 09:58 #54427
nick morrison
Participant
@nickmorrison17107
HI Sam,
Years ago (about ’69), I attended a lecture on the developement of the Advanced Passenger train. Some detail was spent of describing the the profile of the wheels without flanges, instead a conical section was profiled on the periphery.

This was the research into the cause of hunting at speed – pity we ditched it before developement was complete. Hope helps, Nick
19 August 2010 at 09:58 #54428
nick morrison
Participant
@nickmorrison17107
HI Sam,
Years ago (about ’69), I attended a lecture on the developement of the Advanced Passenger train. Some detail was spent of describing the the profile of the wheels without flanges, instead a conical section was profiled on the periphery.

This was the research into the cause of hunting at speed – pity we ditched it before developement was complete. Hope helps, Nick
19 August 2010 at 21:06 #54444
Ian Abbott
Participant
@ianabbott31222
It was a long while ago, but didn’t it involve movement of the axles to align with the track at a tangent to the curve as well as the coning?

Or am I thinking of the ME article.

Ian
19 August 2010 at 23:47 #54448
nick morrison
Participant
@nickmorrison17107
Iam,
Not sure about that, I remember the lecture was fairly technical, I kept the handout for years then …….

I also remember the TV program on the self steering bogies, was it tomorrows world I wonder? Somebody will know I’m sure, got me really wondering. Nick
20 August 2010 at 04:00 #54449
Sam Stones
Participant
@samstones42903
Dear Moderators,

I’ve just been booted off this thread, despite having first logged on as usual. Will this double logging in problem be allowed to persist? It wasn’t the first time either.

Anyway, continuing with this thread, those are interesting and quick responses from you chaps. Thank you.

All of this seems to have stemmed from the fact that the early British rail layouts had to go around the hills rather than over the top. The engines were not powerful enough to haul heavy trains up steep hills. Am I right?

I don’’t have access to ME of any volume, so I’’m unable to follow through with KWIL’’s comment, but thanks anyway. And `Tomorrow’s World’ certainly is a possibility, but Oh so long ago.

At the beginning of this thread, I should have added that (as I recall), the steering system had a hydraulically powered output, but not sure how they sensed the input details.

I’ve pondered the idea of self-aligning wheels, and rolled back-to-back cones turned from bits of bar down the track when my children (and I) had an `N’’ scale layout. Nevertheless, I hadn’t heard of it being referred to as `tyre coning’’. Considering the probable negative issues from coning, although initially more costly, a powered system appears to offer more merit.

For a viable system, a few questions immediately come to my mind. In particular :-

a) A truly conical back-to-back profile is unstable so, can the instability (hunting) be fixed by machining a mathematical profile? I would imagine, YES!

b) While the profile of the tyres might be machined to a particular (mathematical) formula, (a bit like the bias on lawn bowls), will/does the profile last for a respectable enough time before it needs re-machining?

c) And what about the surface of the rails? Wouldn’t they need frequent grinding, to account for wear and thermo/geological movement?

It’’s certainly a challenging conundrum, and although (I digress), I once (c1970) determined the maths and geometry for the mould-release angles for external moulded threads, rimless wheel geometry would tease my aging mind too much. By the way, from my mould-release calculations, I also concluded that lathe lead-screws and split nuts have to be of an ACME form for the same reason.

As I digress even more, I’’m also reminded of the time when, as a young apprentice, we visited the Horwich Locomotive Works in Lostock near Bolton, and watched as (full size) rolling-stock wheels already attached to their respective axles, were being machined. And, being further mesmerized as I watched the very hot tyres were being shrunk on to the wheel cores.

Regards to you all,

Sam
20 August 2010 at 04:02 #54450
Sam Stones
Participant
@samstones42903
Dear Moderators,

I’ve just been booted off this thread, despite having logged on as usual. Will this problem be allowed to persist? It’s not the first time either.

Anyway, those are interesting and quick responses from you chaps. Thank you.

All of this seems to have stemmed from the fact that the early British rail layouts had to go around the hills rather than over the top. The engines were not powerful enough to haul heavy trains up steep hills. Am I right?

I don’’t have access to ME of any volume, so I’’m unable to follow through with KWIL’’s comment, but thanks anyway. And `Tomorrow’s World’ certainly is a possibility, but Oh so long ago.

At the beginning of this thread, I should have added that (as I recall), the steering system had a hydraulically powered output, but not sure how they sensed the input details.

I’ve pondered the idea of self-aligning wheels, and rolled back-to-back cones turned from bits of bar down the track when my children (and I) had an `N’’ scale layout. Nevertheless, I hadn’t heard of it being referred to as `tyre coning’’. Considering the probable negative issues from coning, although initially more costly, a powered system appears to offer more merit.

For a viable system, a few questions immediately come to my mind. In particular :-

a) A truly conical back-to-back profile is unstable so, can the instability (hunting) be fixed by machining a mathematical profile? I would imagine, YES!

b) While the profile of the tyres might be machined to a particular (mathematical) formula, (a bit like the bias on lawn bowls), will/does the profile last for a respectable enough time before it needs re-machining?

c) And what about the surface of the rails? Wouldn’t they need frequent grinding, to account for wear and thermo/geological movement?

It’’s certainly a challenging conundrum, and although (I digress), I once (c1970) determined the maths and geometry for the mould-release angles for external moulded threads, rimless wheel geometry would tease my aging mind too much. By the way, from my mould-release calculations, I also concluded that lathe lead-screws and split nuts have to be of an ACME form for the same reason.

As I digress even more, I’’m also reminded of the time when, as a young apprentice, we visited the Horwich Locomotive Works in Lostock near Bolton, and watched as (full size) rolling-stock wheels already attached to their respective axles, were being machined. And, being further mesmerized, watched as the very hot tyres were being shrunk on to the wheel cores.

Regards to all,

Sam
20 August 2010 at 04:10 #54452
Sam Stones
Participant
@samstones42903
Now there’s a duplication of my thread!!!
20 August 2010 at 08:22 #54456
Brian Oldford
Participant
@brianoldford70365
The link attached may explain things a little better. http://www.railway-technical.com/whlbog.shtml

Note: “Contrary to popular belief, the flanges should not touch the rails. Flanges are only a last resort to prevent the wheels becoming derailed – a safety feature.”
20 August 2010 at 21:48 #54489
Sub Mandrel
Participant
@submandrel
Hello Sam Sam Sam Sam…

Pre 1972 Tomorrow’s World? I would have been only 10, but I’m sure I recall something like that perhaps iot was 2 or 3 years later?

Neil
20 August 2010 at 23:55 #54499
Billy Mills
Participant
@billymills
Sam

Think that Brian’s link does a great job of calming your grey matter. Who in their right mind would have a camera, processor and actuator when a couple of springs would do a better job? No wonder the idea was a Dodo. Almost as good as giving the press loads of food and drink then giving them a high speed rocking in an APT, they did not go green with envy!

Did enjoy the idea of lubricating the rails to ease axles around curves, a very nice example of a trade off that can go badly wrong! Oh the joys of steel on steel.

Your comment on routing around hills is interesting. Early surveying was on horseback and foot to find a good but low cost route as the railways were all commercial for profit affairs. So if you could find a low gradient route ( as the Romans did) then they used it.

Tunneling depends very much on geology and can be very expensive – as IKB found out on the GWR. So if you don’t have to you don’t.

The early rails were laid as flat as possible because the pull and the breaking of the first trains were limited. Some gradients were under 1 in 2000 over most of the run. A 1% gradient halves the load so it was well worth getting a flat route.

Regards,

Alan.

Edited By Alan Gray 1 on 21/08/2010 00:02:47
21 August 2010 at 04:50 #54500
Sam Stones
Participant
@samstones42903
Thanks for all your comments.

It was good to learn that `Tomorrow’s World’ was the source. It had to be pre 1972 because that was when I landed in Australia.

Brian’s link has some very interesting stuff, and certainly resolves several of my issues.

The reason for this thread Alan, comes from having an enquiring mind which hardly ever rests. I’m still curious about the instability/hunting, but it can wait.

Thanks again.

Sam – With’aht’a mus’kit
25 August 2010 at 21:47 #54724
Sub Mandrel
Participant
@submandrel
Somewhere in the last 20 years of ME is an article explaning the profile BR use, which was designed after study of the shape wheels wear to naturally. It has a double taper, or more accurately a taper blending into a curve (not just the root radius).

Presumably the increasing taper causes a non-linearity which stops or damps the hunting you would get with a single taper.

I had enough trouble keeping my Dublo on two (three!) rails when I were a lad!

Neil
26 August 2010 at 01:46 #54735
Sam Stones
Participant
@samstones42903
Thanks Neil,

I had a feeling in my water that there was more to it (ie. hunting) than a simple conical profile.

Could that explain my Double O (Trix with moulded Bakelite track) derailments back in the 40’s?

My newsagent’s order for copies of ME ended sometime in 1972.

Sam
26 August 2010 at 09:30 #54741
KWIL
Participant
@kwil
Here is an interesting link on wheel profiling

http://www.swanagerailway.co.uk/news426.htm
26 August 2010 at 18:50 #54762
Ian Abbott
Participant
@ianabbott31222
I need to go and talk to the wheel turning shop in Buckfastleigh in the next week or so.

I’ll ask them what profile they turn on the main line stuff.

Ian
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