Do we need coned wheels?

[AndyID]

Hi Andy,

 

1:40 is the traditional rail inclination angle/coning in the USA.

 

1:20 is the traditional angle in the UK.

 

regards,

 

Martin.

 

Thanks Martin.

 

Before anyone objects, I should have said "no operational difference at 00 scale"

[AndyID]

 

From NMRA RP-25

 

5. Tread Taper is not required, but 1 degree and 3 degree mold release draft is allowed.

 

(My bold) 

 

Does it really mean "between 1 degree and 3 degree"? Shouldn't it just be "no more than 3 degree"?

[martin_wynne]

Does it really mean "between 1 degree and 3 degree"? Shouldn't it just be "no more than 3 degree"?

 

You are on the right side of the pond to ask.

 

Quite often the NMRA pages read oddly from here. What's the difference between designing it to be 3 degrees, and adding 3 degrees draft angle? There is no need for note 5 at all, because the drawing shows limits 0 degrees to 3 degrees.

 

Martin.

[AndyID]

I wonder if the coning on some model wheels (at least, the cheaper ones which aren't aiming for a known profile) is a bit like the calibration of a car speedometer. The speedometer is allowed to read too high, but never too low.

 

If mass production aimed for cylindrical treads and produced some with negative coning the running would be terrible. So it is easier to aim for some coning, plus or minus a bit. This would tie in with the quite minimal coning we see on some RTR wheels.

 

- Richard.

 

Hi Richard,

 

I think it's more likely to help injection moulded wheels eject from the mould. That seems to be the purpose as far as RP-25 profile wheels are concerned. Obviously, if the profile is machined, that would not be necessary.

 

Cheers!

Andy

[AndyID]

One of these has no taper, one has a 2 degree taper, and one has a 2 degree taper than only goes half-way across the tread.

 

 

[AndyID]

You are on the right side of the pond

 

No. You are on the right side. I am on the left side. (Exits stage left in great haste)

[martin_wynne]

No. You are on the right side. I am on the left side. (Exits stage left in great haste)

 

Only if I'm facing North.

[AndyID]

The wheel nearest the camera has a parallel tread. The other wheel has a 2 degree taper. I can't tell the difference without measuring them.

 

 

The difference might be more apparent on a four wheel wagon, or on the wheels of a steam locomotive. (I think Martin pointed that out already.)

[gordon s]

Hi Guys.  Normally I keep up with these threads as I find the banter fascinating, but I've been away golfing in Holland, so have come to this one a little late in the day.

 

Apologies for going back a few pages in the thread, but there were a couple of points I wanted to pick up on.

 

Let me say up front, I am not an expert on anything, but have enjoyed building my own track.  I did metalwork at school some 50 years ago and spent a while on a drawing board before going into sales, so have a basic understanding of engineering.  What I lack is skill and dexterity in my fingers, but I have been able to make my own pointwork and as such totally agree with Tony's sentiments below.  Believe me, if I can do it, anyone can. Just take it slowly and use the right gauges and a great deal of common sense….

 

To say that building pointwork that gives good running requires a great deal of skill is a fallacy. It must be so or I wouldn't be able to do it (before anybody else says it first).

 

All it needs are some good plans (a certain Mr Wynne of this forum can play a huge part in that) some basic skills and some good jigs and gauges. If you can file a rail to a taper for a blade or a crossing and can use a soldering iron, the rest is really pretty straightforward. The filing can be done away with for anybody not feeling that they can do it as ready made parts can easily be bought in.

 

Good alignment through a crossing nose and a smooth transition from a running rail onto a blade are much bigger factors in smooth running than coning. A flat wheel tread hitting the blunt end of a blade or a badly aligned crossing nose won't stay on the track any better than a coned one. In fact, it will probably be worse as the wheel flange is more likely to be tight up to the running rail rather than the natural centred position of a coned wheel.

 

Tony

 

 

I started playing around with 00 gauges in various standards.  This was ignorance on my part as it took a while reading threads on RMweb to work out the difference between DOGA Fine and Intermediate.  Tried them both with varying degrees of success.  With a ton of stock that had been collected over years, DOGA Fine was ruled out as I didn't want to change all the B2B's, so then tried DOGA Intermediate, which worked OK with most stock, other than those with Ultrascale wheels.

 

Why was I using Ultrascales?  Curiosity initially, but then I bought 10000/10001 from Fiatrains and found their wheels wouldn't run well.  This was a problem with the wheels, not track, so I bought Ultrascale wheels for them to solve that problem.

 

In solving one issue however, it introduced another.  The narrow tread (2.3mm?) on the Ultrascales meant they dropped into the vee when using 1.2mm check rail gaps.  As I was a Templot user, Martin suggested using 00-SF, so I got some gauges and built some crossings to see how they would work.  This was a win/win solution.  I didn't have to change B2B's for DOGA Fine but was able to use the finer 1mm check rail gap and could still run modern RTR wheels, Romford/Markits and now Ultrascale's on one track standard.

 

 

My red.

 

Hi Andy,

 

1. To hell with "typical" crossing angles on an "average" layout.

 

We want a solution which works for all crossing angles on all layouts. As the prototype does. And 00-SF does.

 

2. You consistently fail to make proper (or sometimes any) allowance for the blunt nose. On bullhead track that is 3/4" wide which scales to 0.25mm. So the total crossing gap on 50 thou flangeways is not 2.5mm it is 2.75mm. That's significantly wider than 2.3mm wheels, and as everyone who has tried it knows full well, they do drop in with a very noticeable and objectionable bump. The more so on long crossing angles, which some folks definitely want to use. Have a look at the Eastwood Town topic (an inspiration for many choosing 00-SF) and ask yourself how that would look if Gordon had restricted himself to using only 1:6 crossings. For curved turnouts on running lines, 1:10 is the usual minimum for sensible radii.

 

3. This topic is about the effects of coning. Which does not create any form of "drop-in" bump because it applies only while the wheel is supported on the wing rail. If you wait until the wheel has fallen off the wing rail, the coning is then irrelevant. The wheel will only fall off the wing rail if you use a crossing flangeway which is too wide for it. 00-SF makes sure you don't do that.

 

4. Have you ever actually built a C-10 curved turnout in 00-BF and another one in 00-SF, and tried Ultrascale wheels on them?

 

Martin.

 

Thank you for your kind words on Eastwood Town, Martin.  Hopefully my ramblings through the jungle of building a layout have given some pleasure as I move through a series of  disasters and the odd triumph.  In some ways gauge wars started my interest in golf again as I found it so negative at times.  Having taken several breaks from the discussions and arguments, I now have a much more relaxed view on things and leave the heated stuff to others and just do my own thing….:-)

 

I have posted these before, but these are the picks of the Fiatrains conversion pack from Ultrascale showing the effect of a narrow tread wheel in DOGA Intermediate and 00-SF pointwork.  You can see the drop in the gap as the narrow tread wheel crosses the vee.  The 00-SF version supports the wheel across the gap and there is no drop at all.

 

 

 

Just for the record, I'm very happy with 00-SF and see no reason to change my view.  If asked, I would recommend it anyone. 

 

What surprises me is the reaction from a few whenever 00-SF is brought up.  It isn't the work of the devil and everyone is free to make up their own mind which standard to follow.  

 

All we are doing is passing on our first hand experience.  It is not a crusade or a recruitment drive for a cult, so please let's not go overboard every time 00-SF is mentioned.

 

Apologies again, for going back a few pages, but felt it worthwhile to comment on earlier postings.

[Arthur]

 

 

What surprises me is the reaction from a few whenever 00-SF is brought up.  It isn't the work of the devil and everyone is free to make up their own mind which standard to follow.  

 

All we are doing is passing on our first hand experience.  It is not a crusade or a recruitment drive for a cult, so please let's not go overboard every time 00-SF is mentioned.

 

 

Well said Gordon, thank you.

[Poor Old Bruce]

I'm not too keen on the "conicity" word.

 

Sorry Andy, whether you like it or not, "conicity" is firmly in the language spoken by railway vehicle dynamicists (there's another word you may not take to  ).

 

Edited for typo spotted as I pressed the 'Post' button.

[martin_wynne]

Does it rhyme with city or rickety?

 

You may prefer conicality. The dictionary has both.

 

p.s. also conicalness.

 

Martin.

[Poor Old Bruce]

Does it rhyme with city or rickety?

 

You may prefer conicality. The dictionary has both.

 

Martin.

 

City.

 

As I said, conicity is the word used by the engineers involved in real railway vehicle and track interaction. Conicality just doesn't sound right, even if it is in your dictionary. Does it say if it is related to railway wheels at all?.

[martin_wynne]

You can turn page after page of my dictionary and find nothing about railway wheels.

[Talltim]

The problem is that these days few people under 40 can afford to buy a two bedroom terraced house in much of Britain. House prices in Plymouth are far below what they are in the South East.

 

It's the money you have to spend nowadays to buy a property with a garden in which you can put the workshop-shed that's the big hidden cost

How big a lathe were you thinking of getting? 8-)

[AndyID]

This is conicity

[Andy Reichert]

Thanks for telling me.

 

Andy, I think you are continuing to muddle up two different things. That's the only way I can make sense of your original post.

 

1. the controlled descent of a coned wheel as it runs along the wing rail and off it onto the nose of the vee. Running on the top of the rail and fully supported at all times. That's something which happens on all* crossings, including the prototype.

 

2. the bump caused when a wheel which is too narrow for the track standard falls off the wing rail entirely, into the crossing gap between the wing rails. That's something which is familiar to all users of kit wheels on commercial 16.5mm track, and which the use of 00-SF avoids. (Or DOGA-FINE, or EM, or P4).

 

* traditional rail-built fixed crossings. It can be avoided by ramping up the wing rail on cast crossings, and by modern swing-nose crossings, switch-diamonds, and similar arrangements.

 

Martin.

 

No I'm not. As I've already stated previously, and you did not "understand". You (presumably) misunderstood and failed to calculate the negative impact of sanding crossing vees, while using the same argument to promote 1 mm flange ways to support FINE wheels.

 

See post #1 http://www.rmweb.co.uk/community/index.php?/topic/102548-the-two-main-crossing-bumping-issues-measured/

[davefrk]

Gorden S said ---   ''''It is not a crusade or a recruitment drive for a cult''''    unlike some who keep turning up around here....

 

 

Dave Franks.

[raymw]

I guess, in practice, it won't make much difference, coned, flat, narrow or wide, since  through the frogs the wheels could be made to  run on their flanges. There is generally a couple of ways of doing engineering - precise, close fitting bearings, etc., or slack, plenty of room to move about. Both work equally well, - but it doesn't work if you mix the two principles.  Thanks to the advent of 'the digital age', many have got anally retentive wrt precise measurement of everything, the sort of folk who know the cost of everything, but not the value.

[martin_wynne]

I guess, in practice, it won't make much difference, coned, flat, narrow or wide, since  through the frogs the wheels could be made to  run on their flanges.

 

Hi Ray,

 

That works only if all the wheels have the same flange depth. Which often they don't. Also the infill needs to be metallic, otherwise the wheels lose electrical pick-up and you have the equivalent of a "dead frog" even with a fully rail-built crossing.

 

Generally, it is better to follow the prototype, and use a flangeway gap appropriate to the width of the wheel.

 

regards,

 

Martin.

[raymw]

Hi Martin - I was just stirring the pot....  all these measurements to 0.01mm, and then we stick tension lock couplings on the front, massive gaps between coaches to get round curves, etc. Multi pickups on the locos will overcome the need for a metallic frog infill, I would think.

[martin_wynne]

I was just stirring the pot....  all these measurements to 0.01mm

 

Hi Ray,

 

I haven't posted any dimensions to 0.01mm, and I can't find anyone else who has. That's a silly dimension (less than half a thou) on something handbuilt, often from wood, glue, plastic, etc.

 

Martin.

[AndyID]

Hi Ray,

 

I think the conclusion from all of this that there is no evidence that coned treads improve running (at 00 scale) in the slightest. There is perhaps some cosmetic benefit, but it should be appreciated that the greater the cone angle is, the more problems it can create in terms of electrical contact and smooth running.

 

Those of us who have the option might want to consider whether it's worth it.

 

I also have a hypothesis that, under heavy loads (lots of tension or pressure on the couplings), coning actually makes derailments more likely (at 00 scale), but I don't have any evidence to support that (yet!).

 

Cheers!

Andy

[raymw]

 

I haven't posted any dimensions to 0.01mm, and I can't find anyone else who has.

now that cheap electronic digital callipers are available, I do not think you can get away with merely grinding down the surface of the V with a few strokes of wet&dry   Because we can measure things precisely, we must measure things precisely

 

I believe, can't really be bothered to reason, or test it out, that in the smaller scales, it is the wheel flanges and luck that keeps stuff on the track. Make flanges deep, and it won't fall off. If you add mass and decent suspension, then coned wheels will give a self centring effect, but track will need transition curves, banking, etc, to get the benefits of that, but it is not just the coning, it is the radius where the tread meets the flange that is important, as it is in the full size. When that fails, then the flanges stop it falling off, so why bother with the coning in the first place on the model, which is what most of us are saying?  An alternative could be no flanges and a different cone angle, like a flat belt drive (although the cone there is fairly shallow, and it runs at a more constant speed (belt wobbles a bit while starting up, until it centres.))

[AndyID]

An alternative could be no flanges and a different cone angle, like a flat belt drive (although the cone there is fairly shallow, and it runs at a more constant speed (belt wobbles a bit while starting up, until it centres.))

 

I'm pretty sure that won't work for toffee, but I'm all in favor of you running the experiment

 

The problem here is there is a mountain of anecdotal !@#%%!^ flying around, and precious little hard evidence (please excuse the editorial.)