British Finescale Turnouts - an assessment

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Turnout kits which I'll evaluate on my workbench

First - A Little Background

As Col.Stephens advised early in my planning for a new layout, "In my view using Code 100 rail is akin to running your trains on  girders.  It never looks right and the HO sleeper spacing only  accentuates the toy train look". Once I'd crossed that Bridge, it was clear that PECO Code 75 Streamline was only a half-way house and that their promised Bullhead Code 75 was the way to go for me.

Unfortunately PECO don't seem to have read the Management 101 Manual, "It's better to under promise then over deliver, rather than the reverse". Their much vaunted "Unifrog" Code 75 kit was being promoted over 2 years ago and yet only 2 items had appeared since then #. That set me off looking for other options and I came across British Finescale who were just moving into OO turnout Kits after several years experience with "N" Gauge Kits.

There is a 42 page topic over in "The Other Place" on these developments, British Finescale OO Gauge Kits and the relative simplicity of their assembly caught my eye. The late Gordon S of Eastwood Town fame and legendary track builder noted "If I wasn’t so far down the line, these kits would be a no brainer." I took that as high praise indeed!

# very recent news excepted, it does appear their Unifrog Bullhead range is coming, see Bill's (Longchap) recent topic.


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The Features which Caught my Eye

 Some of these issues I raised earlier so no point in repeating them in detail here, links at Turnouts Link. In summary I liked the availability, increased sizes relative to PECO's range and the ability to shape basic turnouts into various double curves and Y configs.

The first four B7 Turnouts arrived recently and today I set myself the task of assessing the assembly, reported to take about 30 minutes! The beauty of these kits which attracted me was the simplicity so today I can confirm that feature. (but see footnote #)

The first photo shows the track base and cast frog (not yet installed)
.


The 2nd shot shows all rails except the switch blades now installed. The frog is still loose with its wire attached coming out underneath.



The final shot today shows the close up detail of the frog area as per #2 above.



The frog is not yet glued firmly into place, once secure in its sockets it will align perfectly with the exit tracks.

Because of the frog design, it is possible to insulate this from the exit tracks and then avoid the need for isolating fishplates on the inner rails.

Note: Some things being just too good to last, I've recently learnt that the BS OO kits will be moving to all rail construction, dropping the cast frog because of supply difficulties. Too bad, as IMO it was a compelling feature at the expense of a modicum of appearance but hopefully the new releases will still be easy enough to assemble.








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Hello Colin.  What's the story with the rather strange sleeper arrangement in the centre of the turnout?
Terry
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Hi Colin,

Martin has designed some really nice looking turnouts, but to my eyes they don't look GWR. I played around in Templot2 for a few minutes before posting this, a GWR B7 is subtly different to a REA B7, and if you go with older GWR designs (pre-1930s, but many lasted until the 1960s-1970s) dramatically different. The GWR used 2 bolt chairs and rail jogs at the switch blades. I can't see the number of bolts clearly from your photos, but they look like a 3 bolt pattern. Does the kit accommodate a joggle? Like Terry, I had the same thoughts - those missing sleeper sections at the frog look…interesting.

One thing that may be of concern is bending what looks like a straight frog on a straight turnout when curving it. That may result in less than reliable running over the frog if it gets bent out of alignment. Martin makes it very clear that this is a kit, so addressing some of the frog issues is not difficult, and there seems to be some limitations on how far it can be bent. No cast frogs? Probably good news if the kit now supplies soldered ones.

I am unsure of the gauge of the turnout - I am left with the impression that it is HO FS. Shouldn't be a problem with normal stock wheel treads, but there may be problems with FS wheels if the turnout is curved.

Nigel

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Hi Nigel, Terry,

thanks for your feedback.

The kit I have is a B7 OO (HO), not the FS version which is also available so I believe operation of my existing OO stock should not be a issue, by all accounts so far.

As to appearance and accuracy, I strongly suspect that the issue of GWR vs REA would equally apply to the new PECO Bullhead range so I don't feel I'll be at any great disadvantage. TBH having moved from Code 100, the progression to this and PECOs new offering is all I feel I need. Gordon S's expert comment says a lot to my mind and this from Martin Wynne which I'd not read previously. Game Changer

 I've a great many other things of greater importance to me than "2 bolts or 3 etc. etc" especially as I wouldn't know the difference AND can't see them! I guess for anyone to whom this matters, they go along the route of bespoke track building with all that entails.

One issue that I face is I'm rank amateur at fine soldering in a construction rather than electrical context and so welcomed the convenience of this simplified frog design while accepting the inevitable compromises. At this stage the connectors between the frog rails have been primed before darkening, 95% of the area in question would, if see-thru, be sleeper so will be lost to obvious sight once darkened.

"Does the kit accommodate a joggle?" is this also referring to the frog?

Colin

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Taking my time to learn the techniques en route, it still didn't take that long to put the whole kit together, voila…



Overall I'm very happy with the outcome, a basic Dapol Cattle Van ran seamlessly across the frog. You will note that the long, single piece switchblades self-centre when not installed since there is no spring mechanism in this design.



It is a credit that this kit goes together easily and so well to give me a product which ticks all the boxes. Unfortunately I can't give an opinion on the forthcoming releases of their other planned turnout geometries and the diamonds, switches etc. because they will be built with an all track design. This will bring advantages but potential challenges with more complex assembly of both the frog and switch blades. According to reports from the company, more news of these changes should emerge in coming months.


Edit 29 Oct as latest news is there will be no changes to switch blades

 

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Colin, toggle refers to a small kink in the outside running rails which creates a small indentation in the inside of the rails in which the ends of the blades sit.  This provides a smooth passage for the wheel flanges and prevents a jolt as the wheels pass over the ends of the blades.

 I am still confused as to why there is a plastic rectangle halfway along the turnout. What is the purpose of this?

Terry

Edit.  On reflection, is this so you can access the underside of the rails for soldering a wire across?

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[user=711]col.stephens[/user] wrote:
Colin, toggle refers to a small kink in the outside running rails which creates a small indentation in the inside of the rails in which the ends of the blades sit.  This provides a smooth passage for the wheel flanges and prevents a jolt as the wheels pass over the ends of the blades.

I am still confused as to why there is a plastic rectangle halfway along the turnout. What is the purpose of this?

Terry

Edit.  On reflection, is this so you can access the underside of the rails for soldering a wire across?
Terry,

Checking on one of my old Code 100 turnouts I see the RTR solution is a fine rebate cut into the head of the rail where the end of the switch rail sits when engaged.

The definitive answer to the issue is, most appropriately, to be found from Martin on the Scalefour Forum here: Jogged Stockrails which shows exactly what you describe.

 There's no reference to this on the website describing these points or in their assembly instructions. The complete switchblades as supplied are machined almost to a chisel blade edge to sit flush against head and foot of the rail. They are supplied in a neat little holder to protect these delicate ends and it appears to work well with smooth action across the area.

Yes the section you note is for wiring the two rails together. I guess that with careful ballasting it will disappear.

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Hi Colin,

That is a really nice looking turnout. It's interesting that the default timber spacing for a turnout in Templot2 has wider and closer spaced sleepers between the closure and frog exit (as did the prototypes) than the kit. I still can't see whether a) the rails rest on the sleeper with cosmetic chairs on the sides of the rail or it has raised chairs through which the rails slide, and b) how many bolts. For those who like to model GWR track it's an important feature.

I've read most of the articles and messages on curving the turnout, still not convinced that it would handle fine-scale wheels.

Might just try one.It's a kit, so should be amenable to some adjustments.

Nigel





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Some more pics of the turnout details which show the rails sitting above the sleeper in its chair:












I think I mentioned that mine are basic OO but that there is a OO-FS version available as well.

If operation of FS after creating a curve is a concern it might be worth waiting for the all rail versions as these will then have rail repositioning thru the frog unlike my fixed frog version.

When looking at what would be required to create a symmetrical Wye from the B7 -L turnout I generated this set where I progressively added a reverse curve to the thru line using Templot. I took the sideways displacement of the main rail as a measure of the likely stress on the structure.



Radii are in mm, upper is mainline, lower the turnout.





 




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Hi Colin,

Cast or soldered, frogs will resist bending. Still ends up with a straight section through a curve. Which is OK if the running and closure rails are straight when going into the frog. Which they will not if you star bending track. You will get a better idea if you use a curved rather than straight turnout in Templot (and a curviform frog).  I would imagine the stress would be relieved when bending if the webbing is selectively cut. If you are looking for a true wye then I would imagine building from scratch using appropriate chairs and parts would be the way to go, as would a crossover, where you have an S with infinitely changing radii. Prefiled rails and formed frogs should still be available.

I can get an RTR  B6 in EM gauge, as well as the B7 kit (less expensive than retail), through the EM Gauge Society. Bit more choice than OO. All 3-bolts. That said, the sleepers won't match.

Nigel



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[user=1632]BCDR[/user] wrote:

I can get an RTR  B6 in EM gauge, as well as the B7 kit (less expensive than retail), through the EM Gauge Society. Bit more choice than OO. All 3-bolts. That said, the sleepers won't match.

Nigel


Hi guys,

Are those the ones made for them by Peco? If so, they may well be the EM equivelent to their OO bullhead range.
 
Bill

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At 6'4'', Bill is a tall chap, then again, when horizontal he is rather long and people often used to trip over him! . . . and so a nickname was born :)
 
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[user=1814]Longchap[/user] wrote:
[user=1632]BCDR[/user] wrote:

I can get an RTR  B6 in EM gauge, as well as the B7 kit (less expensive than retail), through the EM Gauge Society. Bit more choice than OO. All 3-bolts. That said, the sleepers won't match.

Nigel


Hi guys,

Are those the ones made for them by Peco? If so, they may well be the EM equivelent to their OO bullhead range.

Bill
Looks like it. The B6 closely matches is a similar length to the Peco SL-U1188/ 89 (edit: but has a very different radius, see later post #16 ) which are the only items yet released in their Bullhead range in OO/HO.

Strange that PECO have released EM Gauge 75 product when they have suffered such long delays to their core business of OO/HO or am I misunderstanding the relative market demand between the two Gauges?


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[user=1632]BCDR[/user] wrote:
Hi Colin,

Cast or soldered, frogs will resist bending. Still ends up with a straight section through a curve. Which is OK if the running and closure rails are straight when going into the frog. Which they will not if you star bending track. You will get a better idea if you use a curved rather than straight turnout in Templot (and a curviform frog)…..

Nigel


Nigel,

 Yes, I can see it is a potential issue to have a straight section in the middle of an arc. I thought I'd calculate how big this deviation would be using my possible most extreme case with an arc of radius 2000mm and a frog straight length of 17mm.


The deflection from the arc at the mid point of the frog is derived as follows:
 
The line between the centre of the circle which defines the track arc and a straight frog is shorter than the radius of the arc ®. Call the shortened radius length (a),
frog length (f).

At the frog midpoint this line forms a right triangle with three sides of length, a, r and half the frog length 0.5f

a2 = r2 - (0.5f)2

and the displacement from the true arc at the midpoint of the frog is (r-a)

In the case of a 2000mm radius arc

a2 = 4,000,000 - 72.25
      =3,999,928

a = 1,999.98mm

 so the deviation from the true arc is 0.02mm at the mid point of the frog or about 1/5 the diameter of a human hair. I think my modest OO rolling stock wheels will cope.
 

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Hi Colin (and Bill),

EMGS RTR B7 - Peco bullhead. The kit is cheaper through the society than buying retail (and home made is even cheaper, as I have a good stock of sleepers, code 75 rail and 2-bolt GWR chairs with a 1:20 camber, JLTRT).

Nice to see that the movement is not that great, although it would be more pertinent to calculate the movement at the pointy end, which is where danger lurks, especially with spot-on gauged wheel sets. Out of interest, how sharp is the point? The other issue I didn't raise is that the geometry of the sleepers will be changed as you bend the turnout. Same issue in Templot2 if you bend a straight turnout of course, but that is addressable.

For those interested, code 75 corresponds almost exactly to 90lb rail. Code 100 is somewhere north of 130lb. rail. The G.W.R used 90lb. rail on mainlines Depending on who originally built the branchline and when the G.W.R refurbished it (usually with worn mainline rails), the rail could be considerably lighter. Just to make things interesting. some of the heavier versions of G.W.R rail had thicker and shorter webs. For those who like modeling back in pre-WW1 days, baulk timbers were still being installed in sidings, and it was common to find FB rail in some places where heavier loads were common.



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I've been reading of another advantage of moving to Kit built or total scratch built turnouts.

I'd not realised (but should have!) that the substitution radius -( the "average" radius from the straight track to the exit from the V-crossing #) is determined by the exit geometry rather than the physical length of the turnout.

I'd also not appreciated that this radius for the large PECO turnout U-88/89 is deceptively quite small, 45.67" (See here) given the overall length of the turnout. Finding this a little hard to believe, using Anyrail I put 4 U-89s together end-to-end and fitted a track arc to best match the resulting curve. Sure enough that's the radius, a direct consequence of the Turnout angle of 12 degrees (see above link for Martin's math explaining this)

 In comparison, a straight turnout built to the B6 configuration has an angle of 9.46 degrees and a corresponding substitution radius of ~73" (~1800mm), quite some difference. Again I confirmed this by matching C&L B6 turnouts to a track arc in Anyrail.



Certainly explains all the fuss over building accurate pointwork and the limitations of the PECO offerings. Count me a convert!

  # https://www.rmweb.co.uk/community/index.php?/topic/12156-oo-handmade-points/&do=findComment&comment=1673285

PS for anyone wondering, you cannot easily overlay the arcs on the turnout arrays in Anyrail as they have an annoying tendency to snap together, believing that's what you want!







 




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Hi Colin

In AnyRail, if you add a short section of straight track to the ends of the pointwork ladder, the overlaid curve will not have any open ends that it wants to connect to.

Just a thought

Barry

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Thx Barry,

Yes, silly of me, should have thought of that. Still Doubting Thomas here was satisfied and so it isn't worth reworking the "proof".
I've probably lost the original by now!

Colin

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