A question about 'Finescale OO'

[Ian J.]

This is a tough subject to understand and get the technical language right.

[newbryford]

3 hours ago, Ian J. said:

This is a tough subject to understand and get the technical language right.

 

And the OP probably gave up 4 pages ago......................

[Andy Reichert]

5 hours ago, Ian J. said:

This is a tough subject to understand and get the technical language right.

 

That's because a real railway is a safe and reliable, heavyweight transport, engineering system, with a set of standards that cannot be expressed solely by stating individual dimensions. The physics of keeping and guiding vehicles on the track is similar for an average model railway, but simplified slightly by using deep flanges instead of working suspension.

 

Hobby product makers want to give you a working, just plug and play, substitute that does not require customer engineering know how.  So the track is comprised of  pre-engineered modules, such as complete turnouts, complete locos and cars that are set up to their own inter-operational standards that the average modeller doesn't need to know exist. . . . . . .

 

1. . . . . That is until someone comes along and says "build your own turnouts from raw materials".

 

2. . . . . Or worse, "build better looking turnouts that (somehow) still match the commercials standards you don't know about. 

 

 3. . . . .Or worse still , "build better looking turnouts that (somehow) still match the commercials standards you thought you knew about that secretly changed last year to something you now no longer know about.

 

On the case of "00", Number 3 applies.  To follow through successfully (as possible), you have to understand what a set if Wheel and Track standards is and do your own adaption.

 

For number 1, if you start and stick with a dependable, stable set, of known modelling standards, you can just carry on and build track (and/or chassis) to the same standards and all will function and interoperate 100%.  Examples of proven such standards for smaller scales are P4, EM, HO, P87, and 2mmFS.

 

Andy

 

 

 

 

 

 

[martin_wynne]

38 minutes ago, Andy Reichert said:

Examples of proven such standards for smaller scales are P4, EM, HO, P87, and 2mmFS.

 

Hi Andy,

 

You should add 00-SF to that list. It was devised in the early 1970s by a Permanent-Way engineer who was a senior member of the EMGS. That was at the same time that the present EM standard was finalised (at 18.2mm gauge). He called it "EM minus 2".

 

I later coined the name "00-SF" for it, but the dimensions remain exactly as Roy devised them -- take the EM standard and subtract 2mm from it.

 

The only thing that has changed since the 1970s is that many folk have found that current 00 RTR models run very nicely on it. It is those models that have changed, the "EM minus 2" standard remains exactly the same as it always has been.

 

And having discovered that their models run nicely on 00-SF, they have a tendency to mention that fact to their friends. What the NMRA thinks about it doesn't get much of a look-in.

 

cheers,

 

Martin.

[Andy Reichert]

It's bedtime over here and I want to run the numbers before commenting further. Off the top of my head, I think CK min is larger in NMRA HO.

 

Andy

[cabbie37]

I'm not sure where the OP gave up, but his concentration level has waned somewhat. I think it fair to say, that for his interests, Peco 75 and a DOGA Intermediate B2B will probably suffice... Though I will freely admit that other people may wish to delve deeper into the esoterics..

 

Hugh

 

 

Edited December 15, 2019 by cabbie37
typo

[hayfield]

Finescale in model railway terms in my opinion is far more than track standards. Its the whole appearance to the model and model making. To me its where both model making and artistry come together as one 

[martin_wynne]

9 hours ago, Andy Reichert said:

Off the top of my head, I think CK min is larger in NMRA HO.

 

For optimum running, when the flange of one wheel is running against the rail head, the back of the opposite wheel should just kiss the check rail (as on the prototype).

 

For RP25/110 RTR 00 wheels, the effective flange thickness is around 0.8mm max.

 

(Max because it does depend on the rail head profile. It can be less on well-rounded rail. For UK prototype rail the top corner radius is 1/2" rad = 0.17mm. Most model rail tends to have a sharper top corner than that.)

 

With back-to-back at 14.4mm max, plus 0.8mm flange max, the back-to-flange is 14.4 + 0.8 = 15.2mm max. To just kiss the check rail this corresponds to a check gauge min = 15.2mm for optimum running.

 

If the check gauge is wider than that, the vehicle will be deflected sideways a fraction as the wheelset passes through the branch turnout-side of the crossing (frog). It must not however be smaller than 15.2mm, otherwise there is a risk that the flange will hit the nose of the vee. Hence 15.2mm is the check gauge min and no other dimension is needed for the check gauge. This applies to all track standards using these RTR 00 wheels as supplied, from Peco to 00-SF and all in between.

 

Martin.

[Andy Reichert]

41 minutes ago, martin_wynne said:

 

For optimum running, when the flange of one wheel is running against the rail head, the back of the opposite wheel should just kiss the check rail (as on the prototype).

 

For RP25/110 RTR 00 wheels, the effective flange thickness is around 0.8mm max.

 

(Max because it does depend on the rail head profile. It can be less on well-rounded rail. For UK prototype rail the top corner radius is 1/2" rad = 0.17mm. Most model rail tends to have a sharper top corner than that.)

 

With back-to-back at 14.4mm max, plus 0.8mm flange max, the back-to-flange is 14.4 + 0.8 = 15.2mm max. To just kiss the check rail this corresponds to a check gauge min = 15.2mm for optimum running.

 

If the check gauge is wider than that, the vehicle will be deflected sideways a fraction as the wheelset passes through the branch turnout-side of the crossing (frog). It must not however be smaller than 15.2mm, otherwise there is a risk that the flange will hit the nose of the vee. Hence 15.2mm is the check gauge min and no other dimension is needed for the check gauge. This applies to all track standards using these RTR 00 wheels as supplied, from Peco to 00-SF and all in between.

 

Martin.

 

This is where I'm going to disagree significantly.

 

If you have designed a standard where the effective flange (crossing side) strikes the side of the frog vee simultaneously with the wheel back (check rail side) striking the check rail,  then you have no tolerances for (a) even the minimum amount of practical wheel wobble and (b) inevitable hand laying modelling inaccuracies in constructing the vee, setting the check rail position, etc. 

 

It's still early in the am here in California, so I haven't had my (min) amount of coffee yet. So numbers are yet to worked on. But in principle, model and prototype track and wheel tolerances should include practical running clearance between the effective flange and the crossing vee point and gap,  Those clearances may be (relatively tiny)  on the prototype, but  on smaller scale models, they need to be several thousandths of an inch.

 

More later when I'm fully awake   

 

Andy

 

 

[martin_wynne]

49 minutes ago, Andy Reichert said:

This is where I'm going to disagree significantly.

 

If you have designed a standard where the effective flange (crossing side) strikes the side of the frog vee simultaneously with the wheel back (check rail side) striking the check rail,  then you have no tolerances for (a) even the minimum amount of practical wheel wobble and (b) inevitable hand laying modelling inaccuracies in constructing the vee, setting the check rail position, etc.

 

Hi Andy,

 

1. I didn't design it.

 

2. It is exactly the same in EM, which you previously included in a list of satisfactory standards. 00-SF is simply EM minus 2.0mm. It is also the same in P4 (17.75mm max + 0.40mm max = 18.15mm min):

 

© copied from: http://www.clag.org.uk/p4standards.html#table1

 

3. It is always good practice in handbuilt track to round-off the nose of the vee to match the rail profile, and also to drop the top of the nose of the vee a thou or two below the wing rails to allow for the wheel coning.

 

4. 00-SF, EM, P4, are all designed for handbuilt track, not RTR manufacturing. They all work just fine. Ask the users.

 

cheers,

 

Martin.

[Torper]

Zzzzzzzzzzzzzzzzzzzzzzz.............

[martin_wynne]

7 minutes ago, Torper said:

Zzzzzzzzzzzzzzzzzzzzzzz.............

 

Have you considered not reading topics which don't interest you?

 

A post such as that contributes absolutely nothing to anything.

 

Martin.

[Clive Mortimore]

10 hours ago, cabbie37 said:

I'm not sure where the OP gave up, but his concentration level has waned somewhat. I think it fair to say, that for his interests, Peco 75 and a DOGA Intermediate B2B will probably suffice... Though I will freely admit that other people may wish to delve deeper into the esoterics..

 

Hugh

 

 

Hi Hugh

 

I use code 75 in the station/scenic area of my layout and code 100 elsewhere. I run all sorts of wheels, many I have to open out using my very old J&M back to back gauge but once set they stay put under the coach, loco or wagon and stay on the track. Oddly I have never had to open out a Lima wheel set and they never derail unless pulled off by the vehicle they are coupled to. In the past I have built my own track but these days having a layout working as soon as I can is more fun, I can concentrate on making rolling stock buildings etc and enjoying running my layout.   

 

Enjoying my layout, not worrying about the theory, it works.

 

[Torper]

2 hours ago, martin_wynne said:

 

Have you considered not reading topics which don't interest you?

 

A post such as that contributes absolutely nothing to anything.

 

The thread topic interests me.  What does not interest me is an esoteric discussion between two individuals as to wheel standards that appears to have hijacked the thread and probaby does little more than to discourage people who might have considered going finescale from actually doing so. "Handbuilt Track and Templot" would, I suggest, be the better place for such a discussion.

 

DT

[martin_wynne]

9 minutes ago, Torper said:

"Handbuilt Track and Templot" would, I suggest, be the better place for such a discussion.

 

I don't disagree. I was content to leave it some time ago.

 

But Andy insists on introducing NMRA mass-production considerations into any topic about UK modelling standards, and won't let go. He started with the very first reply in this topic.

 

When misinformation is posted, it needs to be responded to. Everything posted on RMweb will be indexed and available on Google and the Wayback Machine for 100 years.

 

cheers,

 

Martin.

[PMP]

[Andy Reichert]

5 hours ago, martin_wynne said:

 

I don't disagree. I was content to leave it some time ago.

 

But Andy insists on introducing NMRA mass-production considerations into any topic about UK modelling standards, and won't let go. He started with the very first reply in this topic.

 

When misinformation is posted, it needs to be responded to. Everything posted on RMweb will be indexed and available on Google and the Wayback Machine for 100 years.

 

cheers,

 

Martin.

 

Shooting the messenger won't help the OP or the reliability of UK modelling. 

 

 

Hornby has clearly changed their understanding of 00 and their standard dimensions in just the past decade.

 

Whereas The critical B-B of the NMRA standards is unchanged from my "Red Car" bought in 1974 to ny Bachmann street car of 2008. And so they run perfectly together 45 years on.

 

See https://www.youtube.com/watch?v=vgADmMswcmI

 

That's not what you said is it?

 

Andy

 

 

 

 

[Il Grifone]

This thread seems to be getting a tad acrimonious....

 

Any set of standards will work (even Trix Twin!). It's when one tries to mix them that problems arise. For example the NMRA flange is on the thick side at 0.8mm. It will pass through 1mm flangeways - just (the NMRA flangeway is 1.2mm). One of my EM points was allergic to Bachmann wheels which stuck in a flangeway. Undoubtedly this is due to my bad tracklaying, but BRMSB 0.5mm flanges ran without problems. ( EM was originally intended for BRMSB wheels.) The Hornby wheels I have (from the early 2000s) are to BRMSB standards and run perfectly on EM track (mine anyway) once regauged (16.5mm back to back). Previously they were to HD standards (from 1938!). I can't say if any change has been made subsequently, as I don't have any.

 

Quoted dimensions are approximate (NMRA standards are in thou.).

[Andy Reichert]

Sticking to numbers shouldn't cause offense.

 

Note that the NMRA HO flange way is 0.050" MAX/0.035 MIN.

 

 

 

BTW. This is only a working drawing. The numbers below the table aren't needed.

 

It's perfectly legitimate (and practical) to have almost exactly 1mm flangeways for turnouts WITHIN the NMRA HO standards as they are.  And that's without having to alter the track gauge from G MIN..

 

It goes without saying that using such narrowed flange ways will support All UK wheels widths, RTR and Kit.

 

Before anyone points out that requires using the (wider) NMRA back-back setting, I agree. However if the UK RTR back to back settings can be adjusted to fit other mixed wheel solutions, then that can't be an issue.

 

Andy

Edited December 17, 2019 by Andy Reichert
Just needed to add clarification. This is only a working drawing. The numbers below the table aren't needed.

[Andy Reichert]

Hopefully my last post here will give the OP some hope and a possible relatively simple solution.

 

For the sake of not continuing further under this area, I've started a New topic:

 

Fixing "00" Turnouts for "modern" "00" drifting Standards

 

In the "Permanent Way, etc. " section.  So that all ideas on the subject can be considered in a more general setting.

 

Andy

 

 

[88D]

On 15/12/2019 at 08:19, cabbie37 said:

I'm not sure where the OP gave up, but his concentration level has waned somewhat. I think it fair to say, that for his interests, Peco 75 and a DOGA Intermediate B2B will probably suffice... Though I will freely admit that other people may wish to delve deeper into the esoterics..

 

Hugh

 

 

Have a happy Christmas. By the way, other threads are available for light reading over this period. —- just do not ask a question. You know it makes sense.

[Compound2632]

17 minutes ago, 88D said:

just do not ask a question. You know it makes sense.

 

Err, why not? Have I missed something?

[Bernard Lamb]

6 minutes ago, Compound2632 said:

 

Err, why not? Have I missed something?

Yep.

About 70 years of "Gauge Wars" and various long running topics on track standards..

Bernard

[88D]

12 minutes ago, Compound2632 said:

 

Err, why not? Have I missed something?

Possibly the last three or four pages. crying emoji here, if I could

[Ian J.]

It's less to do with gauge wars on this thread, more to do with running quality and two different methods to achieve it - narrow the track gauge or widen the wheel gauge, and consequently how to measure the 'standard'.