H0 16.2mm Gauge Crossings

[roythebus]

Wuppertal Schwebebahn anyone?

[nswgr1855]

On 28/12/2019 at 06:14, martin_wynne said:

 

Hi David,

 

Only Terry Flynn at AMRA can answer that. He always refers to it as H0-SF at 16.25mm gauge/1.05mm flangeway (as shown in Templot for H0-SF).

 

The difference between the 2 pages is a mystery to me, since "check gauge" is mostly relevant to crossings. Either way it is 15.2mm MIN, which is the critical dimension.

 

When I asked him about the gauge difference, his reply was that it related to the manufacture of the track gauges, in that there is no 3-point gauge available.

 

cheers,

 

Martin.

Gentlemen,

A bit late but here is my explanation as to the different track minimum dimensions in the fine tolerance AMRA standard. 16.2mm is minimum track gauge allowed any where. The maximum track gauge allowed any where is 16.8mm, the same as NOROP. These are refereed to in the AMRA standard as limits. The average of these dimensions is 16.5mm, that is the nominal H0 / 00 value. Now you can have your track any value between the limits and get reliable running. Gauge widening is not a problem, If you stick to the AMRA minimum radius standard. You can build a crossing V with the minimum of 16.2mm and fully comply with the standard. It would simply mean you have different flange way values compared to the recommended AMRA values. If you build your track to the 00-SF / EM-2 standard, you are complying with the AMRA standard.  The "RECOMMENDED" AMRA minimum track gauge for FINE TOLERANCE crossing V's is 16.25, and the maximum is 16.3mm. This range allows  flange ways between 1mm and 1.05mm. These values allow for a practical tolerance and results in dimensions suitable for V and K crossings. Its long proven the standard results in derailment free smooth running with most RTR H0 and 00 models. I have successfully built diamond crossings with curves in them which I can push 30 4 wheel wagons through without any derailments. I have run a model of a Lima TGV Duplex at scale 200+Kmh pushing and pulling. Yes Martin is 100% correct, the check gauge is critical, at 15.2mm minimum for track. This is the check gauge PECO uses. Unfortunately the NMRA decided to make their check larger and this has mislead many to publishing and using standards that are not compatible with the majority of RTR track manufacturers. The original NMRA track check gauge was 0.6" =15.24mm, close enough not to be a problem.

 

Cheers,

Terry Flynn.

 

[nswgr1855]

On 21/12/2019 at 04:04, Andy Reichert said:

I'm coming late to this topic, but am wondering why the incorrect statement that normal HO BB is 14.4 mm?

 

RTR HO has a Standard in which the BB dimension is  specified as 14.38 MIN thru 14.61 MAX.  RTR HO models can therefore be expected to have their wheel BB's set anywhere in that range. 

 

Thus there is a serious issue of unmodified out of the box RTR HO model wheels striking the frog vee on a continuous basis..

 

Andy

Hello Andy,

 

Actually there is a problem with the NMRA standard and its 14.61mm Max for many RTR H0 wheels. If the wheel flange is wider than 0.59mm the wheels have a good chance of derailing on most RTR track. Most H0 wheels have a wider flange, and the NMRA RP 25 110 flange is a nominal 0.76mm. Of course if you build track to the NMRA standard, no problem if you like the wider flange way gaps and wide wheels.

Cheers,

Terry Flynn.

[Andy Reichert]

9 hours ago, nswgr1855 said:

Hello Andy,

 

Actually there is a problem with the NMRA standard and its 14.61mm Max for many RTR H0 wheels. If the wheel flange is wider than 0.59mm the wheels have a good chance of derailing on most RTR track. Most H0 wheels have a wider flange, and the NMRA RP 25 110 flange is a nominal 0.76mm. Of course if you build track to the NMRA standard, no problem if you like the wider flange way gaps and wide wheels.

Cheers,

Terry Flynn.

 

You need to send that information to the NMRA right away. 

 

Andy

[Andy Reichert]

PS. In case you confused anyone about my modelling standards, I'm in full agreement with you about not using obviously over width wheels and flange ways.

 

Here are pictures of the wheels of a prototype amfleet car,  . . .

 

 

. . . and a quick and dirty shot of my running model.

 

So like your preference, I use 1.6 mm wide scale wheels with 0.33 mm width scale flanges.

 

 

And near scale 0.6 mm flange ways.  They can even be used on easily modified plastic base NMRA standard  RTR HO track and turnouts.

 

Andy

 

 

[nswgr1855]

15 hours ago, Andy Reichert said:

 

You need to send that information to the NMRA right away. 

 

Andy

 

The facts were made clear to them over 10 years ago.

 

Cheers,

Terry. 

[Andy Reichert]

I think a letter explaining the important details and providing proof is the proper way to do that. Then they know whom to publish their reply to.  "A good chance" is a little vague to be tested, It really needs some independently repeatable statistics. 

 

Martin Wynne has posted a similar opinion that the NMRA  HO standard is flawed here on RM Web, but so far hasn't explained why.

 

Andy

[nswgr1855]

20 hours ago, Andy Reichert said:

I think a letter explaining the important details and providing proof is the proper way to do that. Then they know whom to publish their reply to.  "A good chance" is a little vague to be tested, It really needs some independently repeatable statistics. 

 

Martin Wynne has posted a similar opinion that the NMRA  HO standard is flawed here on RM Web, but so far hasn't explained why.

 

Andy

 

Andy,

Last week I stated: "Actually there is a problem with the NMRA standard and its 14.61mm Max for many RTR H0 wheels. If the wheel flange is wider than 0.59mm the wheels have a good chance of derailing on most RTR track. Most H0 wheels have a wider flange, and the NMRA RP 25 110 flange is a nominal 0.76mm."

 

If the check gauge of your wheels is correct for your track the chance of derailment is 0. No need to prove something that has been known about for over 150 years.

 

I have measured Peco  RTR turnouts using both digital calipers , optical microscopes and a profile projector with with a readability of 0.1 micron.  The conclusion was published on the web, as was the way I derived the various values  many years ago. The NMRA standard is not compatible with PECO track, it proven.  The important thing is if you are using RTR is to pick a proven standard that is compatible with RTR and stick with it. I have proved the AMRA standards are correct and work with most RTR H0 /00 track and wheels, including UK fine scale replacement wheels.  The current AMRA 0 gauge standards are also designed to be compatible with UK fine scale wheels.  I am also critical of the fine scale UK O gauge pseudo standard using a track gauge of 31.5mm, which is less than the AMRA minimum of  31.7mm.  0.2mm makes all the difference between practical tolerances and unnecessary tight tolerances. It's clear to me most model railway standards derive their dimensions  by scaling  down prototype dimensions and do not consider practical tolerances for the manufacture of K crossings. 

 

Terry Flynn.

 

[Andy Reichert]

On 23/03/2020 at 07:16, nswgr1855 said:

Hello Andy,

 

SNIP

 

Of course if you build track to the NMRA standard, no problem if you like the wider flange way gaps and wide wheels.

 

Cheers,

Terry Flynn.

 

So you are OK with the NMRA standards working correctly as is, provided that the track used also complies the standard.  It's just non-standard compliant RTR track that you say can cause derailments.  

 

I'm in full agreement with that. 

 

Andy

 

Edited March 25, 2020 by martin_wynne
image removed as requested

[nswgr1855]

4 hours ago, Andy Reichert said:

 

So you are OK with the NMRA standards working correctly as is, provided that the track used also complies the standard.  It's just non-standard compliant RTR track that you say can cause derailments.  

 

I'm in full agreement with that. 

 

Andy

 

That's right Andy, the reality is the vast majority of RTR turnouts and RTR crossings do not comply with the NMRA standard. On the other hand the vast majority of currently available RTR turnouts and crossings do comply with the AMRA standard.

 

Cheers,

Terry Flynn.

 

Edited March 26, 2020 by nswgr1855
missing word

[Andy Reichert]

I presume your are talking about AMRA intermediate H0 standard ver 1.1, 2010?

 

Who are the largest 6 or so of the vast majority of RTR H0 or HO turnout makers in your understanding?

 

Andy

[nswgr1855]

10 hours ago, Andy Reichert said:

I presume your are talking about AMRA intermediate H0 standard ver 1.1, 2010?

 

Who are the largest 6 or so of the vast majority of RTR H0 or HO turnout makers in your understanding?

 

Andy

 

Most RTR  H0  and 00 turnouts produced today comply with both AMRA standards, the incompatibility between the intermediate tolerance and fine tolerance standards is wheel minimum wheel  back to back. The biggest supplier of H0 track non set track is probably Peco. It dominates the UK and European markets and has a big chunk of the US market now. Other players also have a big chunk of the toy track market, and the better brands also mostly comply with the AMRA standards. In the UK 00 market its Hornby an Peco track that dominates, both comply with the AMRA standards. Peco dominates the Australian market, for what its worth.

 

Terry.

[jim.snowdon]

On 25/03/2020 at 13:31, nswgr1855 said:

 The current AMRA 0 gauge standards are also designed to be compatible with UK fine scale wheels.  I am also critical of the fine scale UK O gauge pseudo standard using a track gauge of 31.5mm, which is less than the AMRA minimum of  31.7mm.  0.2mm makes all the difference between practical tolerances and unnecessary tight tolerances. It's clear to me most model railway standards derive their dimensions  by scaling  down prototype dimensions and do not consider practical tolerances for the manufacture of K crossings. 

You may be critical of the finer UK standards for track (0-MF & 0-SF - 31.5mm and 31.25mm gauge respectively), but they work, and do so with the Fine standard wheels that we have in the UK. They have become quite widely adopted amongst the finescale modellers as a distinct improvement over 32mm gauge.

 

We do, as a rule, work with finer flanges than the AMRA standard - 0.75mm as against 1.0 - 1.1mm but our back to back dimension is correspondingly wider to maintain the check gauge, which is the same as that of the AMRA standard.

 

What is wrong is the UK's 32mm gauge - it is unnecessarily wide in relation to the wheels that we have, with attendant consequences by way of over wide flangeways.

 

Jim

[Andy Reichert]

On 27/03/2020 at 01:57, nswgr1855 said:

 

Most RTR  H0  and 00 turnouts produced today comply with both AMRA standards, the incompatibility between the intermediate tolerance and fine tolerance standards is wheel minimum wheel  back to back. The biggest supplier of H0 track non set track is probably Peco. It dominates the UK and European markets and has a big chunk of the US market now. Other players also have a big chunk of the toy track market, and the better brands also mostly comply with the AMRA standards. In the UK 00 market its Hornby an Peco track that dominates, both comply with the AMRA standards. Peco dominates the Australian market, for what its worth.

 

Terry.

 

I'm surprised Martin hasn't pulled you up on the Fine version where twice your minimum wheel width of 1.05 mm is only just as wide as your maximum crossing flange way of  2.1 mm.

 

E.g. For HO he posted on my reference to the P4 standard:

 

Quote -

 

Posted February 20

 

  On 20/02/2020 at 18:31, Andy Reichert said from the P4 standard explanation:

 

4. Wheel Width Min  >= 2 x Crossing Flange way

 

Martin replied:

 

That should be:  Wheel Width Min = 2 x crossing flangeway + blunt nose width + allowance for top corner radius on rail section + allowance for chamfer between face of wheel and tread.

 

p.s. it is a nonsense to write Min and then add a  >=  relational symbol.

 

Martin.

 

Unquote

 

I would like some consistency in moderation. What's personally considered a failing for HO should be considered a failing for other standards that are more personally preferred on RM WEB.

 

Andy

 

 

 

 

[martin_wynne]

24 minutes ago, Andy Reichert said:

I'm surprised Martin hasn't pulled you up on the Fine version where twice your minimum wheel width of 1.05 mm is only just as wide as your maximum crossing flange way of  2.1 mm.

 

Sigh. I exchanged emails with Terry on that very subject years ago.

 

Andy, are you ever going to give it a rest? No-one on a UK-based forum such as RMweb is much interested in H0 wheel standards, and we have all got more on our minds at present. Here's a picture from my "daily Boris" walk in the local fields yesterday. I was not thinking about H0 wheel width, and just at the moment I don't give a damn how wide you make your wheels:

 

 

Stay safe.

 

Martin.

[nswgr1855]

7 hours ago, Andy Reichert said:

 

I'm surprised Martin hasn't pulled you up on the Fine version where twice your minimum wheel width of 1.05 mm is only just as wide as your maximum crossing flange way of  2.1 mm.

 

E.g. For HO he posted on my reference to the P4 standard:

 

Quote -

 

Posted February 20

 

  On 20/02/2020 at 18:31, Andy Reichert said from the P4 standard explanation:

 

4. Wheel Width Min  >= 2 x Crossing Flange way

 

Martin replied:

 

That should be:  Wheel Width Min = 2 x crossing flangeway + blunt nose width + allowance for top corner radius on rail section + allowance for chamfer between face of wheel and tread.

 

p.s. it is a nonsense to write Min and then add a  >=  relational symbol.

 

Martin.

 

Unquote

 

I would like some consistency in moderation. What's personally considered a failing for HO should be considered a failing for other standards that are more personally preferred on RM WEB.

 

Andy

 

 

 

 

Andy,

This was all discusses years ago. There is no problem with a small amount wheel drop at the limiting condition, it works without derailment, that what it is designed for.  No one makes wheels RTR as narrow as 2mm, the narrowest  RTR fine scale H0 wheel is around 2.23mm and is no problem with track to the AMRA fine tolerance standard. In fact these fine scale wheels work without derailment (sometimes with noticeable wheel drop) on Peco track with flange ways of around 1.3mm. 

Nit pick as much as you like, I know from experience that I do not need to replace or re-gauge  my RTR H0 or UK 00 wheels to run on track complying to AMRA standards. No need for working suspension or compensation either. Check out my Hornby 00 train at speed below. The unfinished track work is to the AMRA fine tolerance standard. Only one set of wheels needed re-gauging. They were over gauge and were derailing on Peco turnouts.

 

[nswgr1855]

15 hours ago, jim.snowdon said:

You may be critical of the finer UK standards for track (0-MF & 0-SF - 31.5mm and 31.25mm gauge respectively), but they work, and do so with the Fine standard wheels that we have in the UK. They have become quite widely adopted amongst the finescale modellers as a distinct improvement over 32mm gauge.

 

We do, as a rule, work with finer flanges than the AMRA standard - 0.75mm as against 1.0 - 1.1mm but our back to back dimension is correspondingly wider to maintain the check gauge, which is the same as that of the AMRA standard.

 

What is wrong is the UK's 32mm gauge - it is unnecessarily wide in relation to the wheels that we have, with attendant consequences by way of over wide flangeways.

 

Jim

Totally agree about 32mm gauge, even for the wider flanged non  UK wheels. 

 

Cheers,

Terry Flynn.

[Andy Reichert]

7 hours ago, nswgr1855 said:

Andy,

This was all discusses years ago. There is no problem with a small amount wheel drop at the limiting condition, it works without derailment, that what it is designed for.  No one makes wheels RTR as narrow as 2mm, the narrowest  RTR fine scale H0 wheel is around 2.23mm and is no problem with track to the AMRA fine tolerance standard. In fact these fine scale wheels work without derailment (sometimes with noticeable wheel drop) on Peco track with flange ways of around 1.3mm. 

Nit pick as much as you like, I know from experience that I do not need to replace or re-gauge  my RTR H0 or UK 00 wheels to run on track complying to AMRA standards. No need for working suspension or compensation either. Check out my Hornby 00 train at speed below. The unfinished track work is to the AMRA fine tolerance standard. Only one set of wheels needed re-gauging. They were over gauge and were derailing on Peco turnouts.

 

 

The current version (RS4522) of the Hornby LNER Suburban Brake coach immediately behind your locomotive has only 2mm wide wheels.

 

I haven't yet taken one apart to see if it has any amount of wheel wobble affecting that dimension.

 

The trouble with calling someone else's manufacturing output your "standard" is that you have absolutely no control over any changes they make.

 

Andy

[Andy Reichert]

2 hours ago, Andy Reichert said:

 

The current version (RS4522) of the Hornby LNER Suburban Brake coach immediately behind your locomotive has only 2mm wide wheels.

 

I haven't yet taken one apart to see if it has any amount of wheel wobble affecting that dimension.

 

The trouble with calling someone else's manufacturing output your "standard" is that you have absolutely no control over any changes they make.

 

Andy

 

Correction

 

My Apologies. My previous stated wheel width dimension was wrong. The Hornby coach has 0.1" width wheels. I mentally mis-converted that measurement from Inches to Millimeters too early in the morning.

 

Andy

[roythebus]

I recently saw a copy of the RDG flange profile book, many many pages of it. B2B is about THE only standard measurement! Flane and wheel profiles all different! Want a copy of it anybody?

[AndyID]

47 minutes ago, roythebus said:

I recently saw a copy of the RDG flange profile book, many many pages of it. B2B is about THE only standard measurement! Flane and wheel profiles all different! Want a copy of it anybody?

 

Hardly any of will scale to model dimensions.

 

BTW, you can reduce "wheel drop" at crossings by using wheels that are not coned. Coning on small scale models is purely cosmetic.

[Andy Reichert]

On 30/03/2020 at 13:45, AndyID said:

 

Hardly any of will scale to model dimensions.

 

BTW, you can reduce "wheel drop" at crossings by using wheels that are not coned. Coning on small scale models is purely cosmetic.

 

Wheel drop at crossings is a bit of a red herring for RTR with rigid chassis and rigid bogies.  Check where the various C of G pressure points are for each model and you'll see what can and can't happen. Generally something has to rock for a single wheel out of 4 or more in a rectangle to dip and that's rarely likely without an outside additional force.

 

If the wheel/crossing dimensions compromised, then it can become much more apparent for models with correctly working suspension. Even then it's still a rolling down hill, then rolling up hill, motion due to the diameter of the round wheels. Not something proto-scale modellers will put up with, but generally unnoticed by RTR users.

 

Andy

[roythebus]

Surely using coned wheels on the model will assist in some small way to reduce friction on curves if you think about it logically. The wheel on the outer rail of the curve has a greater diameter next to the flange than the outer edge of the wheel on the inner rail.

[AndyID]

5 hours ago, roythebus said:

Surely using coned wheels on the model will assist in some small way to reduce friction on curves if you think about it logically. The wheel on the outer rail of the curve has a greater diameter next to the flange than the outer edge of the wheel on the inner rail.

 

Considering how many differences there are in terms of mass, suspension (or lack of), coefficients of friction between rails and wheels, and journal friction it's quite likely there is little or no benefit and even if there is it's only going to be effective on very large radius curves. I calculated how large the radius has to be a few years ago. I can't remember the number now but I do remember it was far bigger than anything I was going to restrict myself to.

 

Oddly enough I have quite a lot of Lima coaches from the last Century. They were very inexpensive at the time and I think they look quite nice. The brass wheels are not coned but I did reduce the enormous flanges on the lathe. They are the smoothest running coaches I have. They never wobble, they sail through the crossings as if they weren't there and they don't seem to resist going round rather tight curves any more than coaches with coned wheels.

[Andy Reichert]

On 12/08/2019 at 03:12, Mark Laidlay said:

I am planning to build some H0 scale Standard Gauge turnouts with the gauge set at 16.2mm at the crossing (out to 16.5 for the rest).  The crossing angle is 1:10.5.  This will reduce the gap between the stock rail and the check rail on both routes thus improving appearance.

I I know that are some 4mm scale users doing similar, any issues when using NMRA (110 mainly) wheels properly gauged?

Mark in Melbourne

 

Going back on topic, the NMRA HO standard is basically asymmetrical as far as stock rail-check rail gap is concerned.  As in all correct model standards, the check rail position is set by the check gauge dimension. Not by the stock rail gap.

 

The commonly misunderstood and thus publicly usually misrepresented "wide" RTR flange ways of NMRA RTR HO turnouts are due to most RTR track manufacturers using the absolute maximum possible flange ways width at the crossing and then matching that width unnecessarily for a  "symmetry" appearance at the stock rail. 

 

It's important to realise that having and using much narrower flange ways on 16.5 mm gauge track are also part of the same NMRA HO standard. And just as compatible with NMRA HO RTR wheels without any adjustments needed. It's just up to the individual track builder to decide which width of the flange ways to make the track to. Hand layers are free to use the standard to it's full possibilities. Or of course, RTR turnouts can be modified as desired to save hand laying altogether.

 

As posted previously, with no dissent, having barely a gnat's whisker greater than 1mm symmetrical flange ways is perfectly possible and practical with all 16.5 mm gauge turnouts, whether commercial or hand built.  In such a case it would be virtually impossible to visually distinguish between that and specifically gauged narrowed track with its 1mm (min.) flange ways.

 

Andy