[34C]

Talking regular RTR OO here, on any 16.5mm gauge track system.

I was very pleased when I first bought a Heljan diesel model to see that they were using a significantly shallower flange on the wheelsets than is normal for RTR OO. The trackholding was not affected, the models stayed on the rails; on a mixture of Peco's streamline codes 100 and 75, and code 75 SMP BH track and points, and soldered construction points, smallest plain track radius 24", smallest radius point 36". (Although I have no set track, it was at the time possible to try these models on a friend's set track layout - all purchased from circa 2010 - and they were trouble free if operated at modest pace through the points, no problems on plain track curves.)

Even the two Heljan steam locos I have (O2 2-8-0) tempt fate by offering the shallower flange on a rigid 8 coupled chassis, yet perform perfectly on track.

Some Accurascale and Hattons wagons have recently come my way, and these too have shallower than normal flanges, very good too.

So, is there any objection to a shallower flange becoming general in RTR OO?

I like it for the benefit to appearance, and it would be handy on a few UK steamers which have their wheels closely grouped and are necessarily 'dimensionally massaged' to make a practical running mechanism, because the normal flange depth fouls (e.g. C1, H1, H2, atlantics, Peppercorn A2 pacific, BR std 9F). There may well be more such, these are the examples I know; I'll be particularly interested to see how Hornby handle the problem on their all new tooling 9F: the present RTR models are both 'massaged', Hornby, correct overall coupled wheelbase length, but axle centre spacings varied, Bachmann, axle spacings consistent but slightly overscale, resulting in an overall coupled wheelbase 2mm over scale.

 

[boxbrownie]

I think flange width and toe and tyre angle is far more important than the flange depth, so I’m with you…make’em shallower.

 

[dwb]

Whenever 'finer' wheel standards get mentioned, I automatically think 'RP25' which is an NMRA standard https://www.nmra.org/sites/default/files/standards/sandrp/pdf/RP-25 2009.07.pdf

Sometimes manufacturers' model details will reference RP25, sometimes not. The spec for Accurascale cement wagons mention RP25.110 - https://accurascale.co.uk/collections/wagons/products/vtg-castle-cement-r Perhaps other wagons also have RP25.110 wheels as well even if the spec doesn't mention it.

Finer wheel flanges do look better than the 'pizza cutters' you find on some stock but your track laying needs to be up to it as well.

David

 

[Graham Plowman]

All British outline manufacturers have been using finer flanges on their metal wheels since around 2000.

The days of 'pizza cutter' flanges were associated with Lima and they were an earlier phenomenon which changed in the mid 80's: Lima Wheels - Model Railways On-Line

The later Lima flanges were still large by today's standards but they were an 'improvement' on the earlier flanges.

When my son was small, we purchased the ubiquitous Thomas the Tank set for him. Even in those days, the flanges on the loco were good, but the loco and rolling stock kept coming off the track.
And this is the crux of the issue: if people are going to run these finer flanges on toy trainset 10 inch radius SetTrack curves, don't expect the stock to stay on the rails.
When Thomas ran on Ashprington Road with 5 foot minimum radius curves, he ran perfectly and never derailed. As @dwb correctly noted, track laying standards need to be up to scratch as well.

 

[34C]

You will have noticed I didn't quote any dimensions or RP's.

Now, the usual choice of RTR OO manufacturers is some interpretation of RP25-110, which corresponds fairly well to the tyre and flange profile of kit wheels over the years from Jackson, MGW, Gibson, et al. This works, but the flange is around 1mm depth from root to flange tip.

What Heljan have done on their OO product (since I first saw it) is much the same tyre and flange profile, but the flange circa 0.6mm depth. This looks much better, and there's no problem on track. My recent first exposure to Accurascale and Hattons wagons, revealed that they have adopted this practise.

We are up against the chronic weakness of RTR OO that there simply isn't any standard worth the name to describe this, unless someone here knows different?

Whatever, I want more of this. Personal whittling of wheelsets has me convinced that yet better is possible on Peco streamline or better track if the following is observed:

... flange width and toe and tyre angle is far more important than the flange depth, so I’m with you…make’em shallower.

Further comments?

 

[Mark Mugnai]

Only to mention (yet again) that here in the States we have benefited from the above NMRA standards for decades. Because of this, the only issue I ever had came from trying to run German pizza-cutter wheeled stock on rail smaller than code 83...and 83 is smaller and looks better (to me anyway) than the code 100 I first started with, back in 1970.

Yes, all HO and OO should follow those standards...my opinion.

Mark in Oregon

 

[Graham Plowman]

Only to mention (yet again) that here in the States we have benefited from the above NMRA standards for decades. Because of this, the only issue I ever had came from trying to run German pizza-cutter wheeled stock on rail smaller than code 83...and 83 is smaller and looks better (to me anyway) than the code 100 I first started with, back in 1970.

Yes, all HO and OO should follow those standards...my opinion.

Mark in Oregon

Be aware that the NMRA standards are applicable to US HO outline.
I am aware that several UK outline manufacturers use an interpretation of the NMRA standards, but the UK had standards way back in the 60's and 70's in the form of BRMSB. I believe that the like of Romford and all the other non-RTR manufacturers used to work to BRMSB standards.

But on the topic of standards, agreed, scale-appropriate standards should be followed. Please, not measurements made up by an individual (they are not 'standards') like OO-SF !!!

 

[Mark Mugnai]

"Be aware that NMRA standards are applicable to US HO outline".

Yes, but it doesn't matter what "outline" the model is (US,UK, whatever) if the track gauge is the same, correct? It would appear that by moving towards a smaller flange, the model makers are becoming more "in line" with those NMRA standards... which means that regardless of where you are, or what you run, everything would be interchangeable. A very good thing, in my estimation.

Mark in Oregon

 

[Graham Plowman]

Personally, I am of the view that the 'baseline' standard for wheel and flange design of models should be that of the applicable prototype jurisdiction. Presumably, NMRA standards align with American prototypes ?
Thin flanges does not necessarily equal NMRA standards, for example, there are others such as the P4 standards in the UK and the Europeans have their own standards too.
As a modeller of the Western Region of British Rail in Devon, set in the 1960's and early 1980's, I am not aware that I need to have wheel/track standards that make my rolling stock 'interchangeable' with any prototype that didn't run in the area - for a start, the loading gauge and kinematic envelope would be different.

 

[Mark Mugnai]

I absolutely see what you're saying, and agree. If that's someone's approach, that's great. I love looking at pictures of layouts based on a particular era, location, etc.

I guess my point was that if I want to run trains of any prototype, it's great if they conform to some sort of standard so tracking is not an issue.

Mark in Oregon