Not quite 00 or H0

[hayfield]

I must admit that hearing about coarse scale P4 for the first time does have some merits, of wider track width coupled with slightly wider flangeways. At a guess akin to 00sf being a slightly compressed 00 with EM tolerances. With P4 course I guess we are looking at 1 mm flange ways, rolling stock wheels would be east to adjust, as I guess would modern diesel and electric motive power, I guess for steam you would have to use Gibsons and the back to back would be 16.83 mm

 

Coming back to reality, is it worth it for a gain of 0.63 mm ?

[AndyID]

Hi Gordon,

 

Just about to pack it in here for the night!

 

Using the ruler in Templot, the last timber in the template clocks in at 31.6 mm. SMP OO sleepers seem to be around 31.5 mm long. C&L say their's are 32 mm, but I cannot confirm that from an actual sample.

 

I'll attach some SMP to the tiebar end tomorrow so we can see how it looks. If it's a bit too dodgy, we could always crank the scale down to 81.

 

Cheers!

Andy.

 

 

EDIT: Come to think of it, if you look at the earlier photos I posted, you'll see that SMP sleeper lengths are a perfect match with the plain track produced by the Templot template. 

[martin_wynne]

I must admit that hearing about coarse scale P4 for the first time does have some merits, of wider track width coupled with slightly wider flangeways.

 

Hi John,

 

Actually, it has very little merit. This is where H0 gets it wrong.

 

If you use an exact-scale track gauge, you must also use an exact-scale wheel profile. Otherwise the distance across the wheels will be greater than scale. Then they won't fit inside splashers, behind crossheads, inside bogie sideframes, etc., and there certainly wouldn't be sufficient room for the extra sideplay we need to go round model curves.

 

All H0 models are over scale width for this reason, because they use wide RTR wheels on an exact-scale track gauge. The extra width doesn't show up too badly on American style models, but for UK steam-outline models H0 is a non-starter if you want accurate scale models.

 

The sensible thing if you want the greater practicality of overscale wheel profiles, is to reduce the track gauge accordingly, to keep the distance across the wheels small enough to fit within the models. EM gets it about right for curves down to about 30"/750mm radius. 00 rather overdoes the gauge reduction, so that models with wider than scale wheels can have enough sideplay to go round train-set curves down to 15"/375mm radius.

 

Those who got us where we are today weren't daft, and have given us 3 sensible working options for different layout conditions. 00, EM, P4. All allowing the use of accurate model bodies without distorted splashers, outside cylinders, bogie frames etc.

 

If you want coarse scale P4 you can have it now -- it's called EM.

 

regards,

 

Martin.

[Campaman]

BTW, is that frog switch well known, or is it worthy of a new topic? Probably could do with being hidden under a ramp

 

I for one would be very interested in more information on that frog switching, I have never seen it done like that and am looking for alternative ways to do it as I dont want to use point motors, I want to use some for of hand operated switching.

[hayfield]

SMP did a very simple mechanical one using an insulated tiebar.

 

The tiebar had a L section of metal connected to the centre of the tiebar, with the foot coming up about 1 mm.

The 2 sleepers behind the tiebar had central isolation gaps, either side of the gaps were pieces or brass/nickel wire which were soldered to both sleepers and extended to the tiebar.

When the tiebar was moved to one side it touched one wire, when moved the other way it touched the other wire. its a simple job to run a wire from a tiebar to the common crossing. I will see if I can take a photo. SMP used to sell a fibre glass tiebar ready to go but one can easily be made with some copperclad strip

[martin_wynne]

I must admit to being somewhat (completely) lost on this

Martin - would you have time to post a screen shot of the currently used 00 turnout (with 32mm sleepers) alongside what is being proposed/discussed please?

 

Hi Brian,

 

What Andy is doing (not necessarily the same as proposing ) is to use a scale of 3.75mm/ft* to model the track, and reducing the gauge to 16.2mm with 1.0mm flangeways to match 00-SF (which uses track scaled at 4mm/ft).

 

We don't have any available components such as bullhead rail or chairs for this 3.75mm/ft scale, so the result is bound to be something of a hybrid of different scales.

 

*I prefer the mixed metric-imperial units because:

 

1. it conforms to the existing convention for model scales in the UK.

 

2. in Templot it is a great help in avoiding confusion -- dimensions in mm relate to the model; dimensions in inches relate to the prototype.

 

At 3.75mm/ft the 16.2mm track gauge is equivalent to prototype 4ft-3.84in track gauge. I don't know of any prototype track using that gauge, so we can only make an engineering guess as to the likely length of the sleepers. They have to be long enough for the pyramid of ballast below each rail to distribute the load onto the formation, without wasting timber unnecessarily. If I was designing track for such a gauge, I would specify 8ft long sleepers. That's just about right to do the job, and is a convenient size to be supplied by the timber mill.

 

At 3.75mm/ft that becomes 30mm long sleepers, so 2mm shorter than the usual 32mm sleepers for 00 track.

 

However if you think 4ft-3.84in track would have 8ft-6in sleepers (the next size up from the timber mill) at 3.75mm/ft that becomes 31.875mm, nearer to 32mm.

 

I will post some screenshots of these options shortly.

 

I don't know any accurate figures for the sleeper length for flexible tracks.

 

Note from the C&L web site that the 00 moulding tool has broken in half, and a new one must be made. So if it was desirable to change the length of the sleepers, now is the time to ask C&L about it.

 

regards,

 

Martin.

[RichardS]

Hi John,

 

Actually, it has very little merit. This is where H0 gets it wrong...................

 

If you use an exact-scale track gauge, you must also use an exact-scale wheel profile. Otherwise the distance across the wheels will be greater than scale. Then they won't fit inside splashers, behind crossheads, inside bogie sideframes, etc., and there certainly wouldn't be sufficient room for the extra sideplay we need to go round model curves.

 

All H0 models are over scale width for this reason, because they use wide RTR wheels on an exact-scale track gauge. The extra width doesn't show up too badly on American style models, but for UK steam-outline models H0 is a non-starter if you want accurate scale models.

 

The sensible thing if you want the greater practicality of overscale wheel profiles, is to reduce the track gauge accordingly, to keep the distance across the wheels small enough to fit within the models. EM gets it about right for curves down to about 30"/750mm radius. 00 rather overdoes the gauge reduction, so that models with wider than scale wheels can have enough sideplay to go round train-set curves down to 15"/375mm radius.

 

Those who got us where we are today weren't daft, and have given us 3 sensible working options for different layout conditions. 00, EM, P4. All allowing the use of accurate model bodies without distorted splashers, outside cylinders, bogie frames etc.

 

If you want coarse scale P4 you can have it now -- it's called EM.

 

regards,

 

Martin.

 

This is probably one of, if not the most useful posts I have ever seen on any forum. It explains in a few lines to the less than technical orientated (like me) exactly what the issues are. Apparently obvious when explained but I am sure rather cloudy to many.

 

Could you perhaps go a stage further and explain why OO-SF uses a gauge of 16.2 please? I assume this is so that the gauge can be widened to 16.5 on curves. 

 

Many thanks Martin, you have the patience of a saint. :-)

[hayfield]

Here is the tiebar

 

 

Fibre glass with the centre plate

 

 

I have omitted the switch rails, but the 2 wires are spaced slightly wider than the plate they touch.

 

 

In place on a layout, but only used as tiebars as the point motors switch polarity's

Easy to have a hole drilled under so the wire just drops straight down, if using thin wire it can be painted (where not touching the metal plate) to hide it

[martin_wynne]

Could you perhaps go a stage further and explain why 00-SF uses a gauge of 16.2 please?

 

Hi Richard,

 

Thanks for the kind words.

 

The first thing to say is that if you are using only RTR models, you don't need 00-SF. They run perfectly well on the 60-year-old 00-BF track standard. The only reason to use 00-SF would be to get the improved appearance of narrower flangeway gaps -- but at the expense of a greater restriction on minimum radius (at 16.2mm gauge) and the need to be more careful about checking wheel back-to-backs.

 

00-BF is 16.5mm track gauge with 1.3mm flangeway gaps. (Note that 00-BF is not available from C&L.)

 

00-SF is 16.2mm track gauge with 1.0mm flangeway gaps.

 

Both of them use the same 15.2mm check gauge for the check rails.

 

For wheels to run properly on a track standard, their width must at least double the flangeway gap*. Otherwise when running through a crossing (frog) they can drop into the wide gap across in front of the vee. With a bump.

 

So for 00-BF that means that the wheels must be at least 2 times 1.3mm = 2.6mm wide. RTR models nowadays have wheels 2.8mm wide, so they are fine on 00-BF and cannot drop into the gap at the crossing. An object 2.8mm wide cannot fall into a space 2.6mm wide. The wheels remain supported on the wing rails and run smoothly through the crossing (frog).

 

But not all 00 modellers use only RTR models. There are a great many rolling-stock kits available from the trade, and there are still a few modellers (not many left now) who buy wheels and build 00 models from scratch.

 

Unfortunately the wheels supplied by the trade with such kits do not comply with the 00-BF track standard (although few of them tell you this). Typically they are 2.3mm wide, and can easily fall into a gap 2.6mm wide. Consequently when used on 00-BF track such kit models are very bumpy running over crossings (frogs).

 

The idea of 00-SF is to reduce the width of the flangeway gaps so that such wheels do not fall into them. With flangeways at 1.0mm the gap across in front of the vee is 2.0mm, so clearly wheels 2.3mm wide cannot fall into it, and run smoothly over the crossings.

 

In order that 00-SF track will accept 00 wheels set to the existing back-to-back, it is important to keep the check gauge the same as 00-BF, at 15.2mm from the opposite rail.

 

It is very desirable that the check rail gap should be the same as the crossing flangeway gap**, to allow for the construction of complex track formations. So with a check gauge of 15.2mm and a gap of 1.0mm that makes the track gauge 16.2mm.

 

Notice that the 16.2mm track gauge is derived from the other dimensions, not the starting point.

 

The result is the 00-SF track standard which will accept modern RTR*** models, and also provide smooth running for kit-built models.

 

It also has the advantage that the narrower 1.0mm flangeway gaps look much better than 1.3mm. (An exact-scale flangeway gap would be 0.6mm.)

 

*And preferably a bit more if you want to correctly model the prototypical blunt nose on the tip of the vee.

 

**Except where there is gauge-widening on sharp curves.

 

***Assuming the manufacturers have good quality control. The back-to-back must not be less than 14.3mm.

 

regards,

 

Martin.

[polybear]

I must admit that hearing about coarse scale P4 for the first time does have some merits, of wider track width coupled with slightly wider flangeways. At a

Hi John,

 

Perhaps you could try suggesting it on the Scalefour Forum....    It should provide plenty of entertainment for the rest of us

 

It could be even better than the thread discussing the use of EM wheels on 18.83 trackwork

 

polybear

[martin_wynne]

Perhaps you could try suggesting it on the Scalefour Forum....    It should provide plenty of entertainment for the rest of us

 

It could be even better than the thread discussing the use of EM wheels on 18.83 trackwork

 

Hi Brian, John,

 

In fact it is already in Templot -- see the gauge setting called EM4.

 

18.8mm gauge with 0.8mm flangeways. A sensible set of dimensions for those who want to use EM wheels on P4 track gauge. It suffers from the same failing as H0 in that the distance across the wheels is overscale, with no room for sideplay on sharp curves without modifying models.

 

See: http://www.scalefour.org/forum/viewtopic.php?f=5&t=3915

 

My view is that if you want to use EM wheels, the better thing to do is build EM track.

 

Martin.

[AndyID]

I for one would be very interested in more information on that frog switching, I have never seen it done like that and am looking for alternative ways to do it as I dont want to use point motors, I want to use some for of hand operated switching.

 

I'll start a new thread in the track construction forum. This thread is already complicated enough

[martin_wynne]

That would be good to see, Polybear, as I'm still a little confused about the length of sleepers beyond the tie bar on the turnout where is has to connect to SMP or C & L flexitrack.  Both of those use 32mm sleepers and unless I have misunderstood, the end sleepers on turnouts are proposed at 30mm...

 

Hi Gordon,

 

I have now added 3.75mm/ft scale on 16.2mm gauge to Templot, for anyone who wants to try it. I have given it the distinctive name 00-DN to avoid confusion with anything else (DN = Double N). It will be in the next Templot program update.

 

 

 

Note that just because I put things in Templot for users' convenience doesn't mean that I am necessarily recommending or proposing them. My own view is that the existing 00-SF settings in Templot produce the most sensible results -- a 4mm/ft scale model of prototype 48.6" gauge track on 8ft sleepers. If the proportions don't look quite the same as 56.5" gauge track, that's because it isn't 56.5" gauge track.

 

For 00-DN I have left the sleeper length on the default 8ft-6in, which is probably a bit excessive in prototype terms in relation to the track gauge, but means they scale to 31.9mm for a good match with existing track having 32mm sleepers. If you change to 8ft sleepers, they are then 30mm long at 3.75mm/ft.

 

Here below is a screenshot, 00-SF in the middle. The .box file is here if you want to load it in to Templot and do some trial planning and printing:

 

   00_dn_templates.box

 

Be careful with this file because it contains two different scales. That's not normally the case with a Templot file. It can get confusing and produce unpredictable results -- on the sketchboard for example. Don't mix this file with your existing Templot files, restart Templot to try it.

 

 

regards,

 

Martin.

[gordon s]

Thanks Martin.  I have found this discussion of interest, but will continue to build in 00-SF.  For me there is no difference in option 1 and 2, whereas option 3 creates the illusion of a slightly wider gauge.  However, option 3 then falls over by the use of 30mm sleepers and would give me a problem of alignment when using RTR flexitrack from SMP or C & L with their 32mm sleepers.

 

It's been a fascinating journey, so thanks Andy for an thought provoking topic.

[AndyID]

Hi Gordon,

 

The model I made isn't using 30 mm sleepers. It's using 31.6 mm sleepers.

 

They are 8.5 feet = 102"

 

Divide by the scale (my version is 1:82) 102/82 = 1.244"

 

Multiply by 25.4 to convert to millimeters gives 31.6 mm

 

Martins Version (option 3)

 

102 / 81.28 = 1.255"  converted to millimeters is 31.87 mm, which probably within tolerance for 32 mm.

 

 

I'm not trying to talk you into using this idea, but it might be a pity if you dumped it for the wrong reasons. On the other hand, if you have already constructed a lot of turnouts to OO-SF, it might look a bit odd if you have a mixture of scales.

 

Cheers!

Andy

[gordon s]

So if I understand correctly, the turnout you made was essentially option 1 then with 8'6" (32mm) sleepers whereas Martin's option 3 was based on 8' (30mm) sleepers….:-)

 

The eyes can certainly play tricks with you, particularly with the added dimension of photography.  I thought your turnout gave the impression it was a wider gauge purely from the photographic comparison.  Looking at the templates Martin has created 1 & 2 look identical whereas 3 does create that illusion of a wider gauge.

 

Of course it will all look different in the morning.  A glass or two of Malbec also adds another dimension…:-)

 

I like to think I have an open mind on these things, hence my interest, but as you say ET has so many turnouts already built, I wouldn't consider any change at this time.

 

Having said that any post that presents lateral thinking or innovation is always of interest...

[AndyID]

If we picked a scale of 1:81 and option 8.5 foot sleepers, Templot would draw sleepers for us that are 31.99 mm long

[AndyID]

I just realized Martin put numbers on them. I thought option 1 was at the top!

 

Yes, option 1 would be closest to my model, and coincidentally, that is compatible with the length of SMP sleepers and probably C&L sleepers too, although SMP sleepers are slightly wider than ideal.

 

I'm going to press-on and apply this to my layout. I'll post more photos as work progresses (if it progresses). It will be interesting to see how a formation of several points and track look when ballasted on an actual layout. I think it will work for me, but beauty is in the eye..... 

 

The following graphic attempts to explain why the gauge reduction affects the appearance (for some people at least).

 

The rectangles represent the area corresponding to the top of a timber that is visible between the inside edges of the rails. In the case of "Real" that is 4' 8.5" x 12", and that ratio defines the aspect ratio of that area.

 

On the left are how the aspect ratios appear for OO at the top and what I'm calling 1:82 at the bottom.

 

On the right, the aspect ratios are unchanged, but OO and 82 are scaled up to have the same apparent gauge as REAL.

 

 

[AndyID]

I for one would be very interested in more information on that frog switching, I have never seen it done like that and am looking for alternative ways to do it as I dont want to use point motors, I want to use some for of hand operated switching.

 

Please see new thread at http://www.rmweb.co.uk/community/index.php?/topic/97918-frog-switch-for-copperclad-construction/

[martin_wynne]

Using the ruler in Templot, the last timber in the template clocks in at 31.6 mm.

 

Hi Andy,

 

Just to add that you don't need the ruler for this -- the length of every timber can be seen in the shove timbers dialog.

 

Could you possibly post a side-on pic showing the wagon standing on the crossing (where the timbers are evenly spaced at 2ft-6in)? It is not possible to judge very much from the centre portion of a turnout because the spacings vary for each turnout size (a whole number of timbers have to fit within the geometrical lead length for the turnout).

 

For 00 stock on H0 track there is an obvious effect of having too many sleepers between the wheels of a wagon (very noticeable on Peco track). For your hybrid scale this effect will be reduced, possibly enough not to be noticed.

 

 

regards,

 

Martin.

[AndyID]

Thanks Martin. Another of the many features in Templot I had forgotten about!

 

Pics attached. I would think the well trained eye will detect the linear underscale nature of the track, but my eye isn't that well trained.

 

(For laughs I thought of posing a Trix 16t mineral as well, but I'd have to dig through a lot of boxes to find it  )

 

 

Ah, the cruel tyranny of the extreme closeup!

 

 

 

[martin_wynne]

Hi Andy,

 

Thanks for the pics.

 

With timbers at 2ft-6in centres, a 9ft wheelbase wagon should span about 3.2/3rds timber centres, see: 

 

 http://PaulBartlett.zenfolio.com/lneropenwood/e1744777e

 

Your wagon is spanning about 4 timber centres, so not a significant difference. I don't think many would notice it.

 

regards,

 

Martin.

[AndyID]

Thanks Martin.

 

Gosh, you know there's not much in it is there. I really like the proportions of that turnout, but I'm not sure if it's because of the scale trick or it has more to do with the fact that Templot produces highly realistic curved turnouts!

 

To get a different perspective I'm going to make something that would be equivalent to a RTR turnout. Any thoughts on what would be a good size for that? I'm thinking something with an equivalent radius of around 30".

 

BTW, how does the rail height strike you? It's Code 70, which I have a lot of. Code 83 might have been a better choice for FB turnouts. I'm not sure.

 

 

EDIT: Answering my own question - Looks like a curviform A V-5 might be about right. The External Geometrical Radius is 31.01" and the smallest radius is 28.8"

 

Here goes!

[martin_wynne]

Hi Andy,

 

Unless it's for industrial lines, sidings, light railway, etc., or very modern, the height of UK flat-bottom rail is 6.1/4" (FB-109, BS-110A, BS-1113A sections). That scales to code 82 at 4mm/ft and code 77 at 3.75mm/ft. So your code 70 is perhaps a bit small for that.

 

The next UK size down, for sidings, etc, is FB-98 section which is 5.5/8" high. That scales to code 74 at 4mm/ft and code 69 at 3.75mm/ft. So your code 70 is just about right for that. It does look a bit light for main-line use in your photos. I should add that there isn't much FB-98 rail in use because usual practice is to use second-hand running-line rail for sidings rather than brand new.

 

It is actually quite difficult to judge track photographs until ballasted -- that's how the vast majority of real track is seen.

 

To replicate RTR track it is better not to use the REA switches. You can usually get a better match using old-style loose-heel switches. There is a file of Templot templates matching Peco turnouts available here:

 

  http://85a.co.uk/forum/view_topic.php?id=294&forum_id=10

 

 

Above shows the nearest match to a Peco Large Radius turnout. It has a GWR 10ft curved switch and a 1:6 curviform V-crossing. That's not a common size, it was generated simply to get as close as possible in 00-SF to the Peco dimensions.

 

For the short set-track style turnouts, you may do better to use gaunt turnouts with zero gaunt offset. Say a 1:4.5 curviform -- see template > gaunt options > menu items.

 

 

That's 00-SF which at that radius will need gauge-widening on the turnout road of course.

 

(Gaunt turnouts don't have a proper switch, so you would need to recess the stock rail in RTR fashion to produce a usable result.)

 

regards,

 

Martin.

[AndyID]

Hi Martin,

 

Yes, I thought the rail might be a bit on the low side. We will see how it looks when it's ballasted and combined with Code 75 SMP bullhead. If it looks too much like a light railway I may have to get some Code 83.

 

Do you think it would it be terrible to continue with the REA turnout? I've already stuck down the timbers and cut the V rails (see new topic)

 

I'm not really trying to replicate the RTR "look" - more a case of trying to produce pleasing looking smallish radius turnout. Personally, I don't care so much for the perpendicular timbers. I think it might accentuate the small radius and I was hoping to disguise that a bit by using a symmetrical crossing (sorry if my terminology is not correct).

 

BTW, if you have not already incorporated a deliberate error into the templates that Templot produces, I think you might consider doing that.

 

Thanks for all the information!

 

Best,

Andy