Turnout construction - Question here please.

Discuss the prototype and how to model it.
davebradwell
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Re: Turnout construction - Question here please.

Postby davebradwell » Mon Dec 21, 2020 2:33 pm

Well, Paul Cram, I've made crossings up into soldered units by various means but was never convinced that tolerances of a few thou' could be met by sticking flexible plastic chairs round something to hold it. The position could also be easily influenced by the tracks leading off so I felt critical areas needed soldering. I have a couple of single slips and a C8 that are all glued and they work but the bumps and rattles suggest that the stock is pushing the rails into the correct position. Why do we start track laying with the main-line?

Terry, the dropper you described is exactly the type that's given me so much trouble. I suspect that tiny movements of the rail during the daily temperature cycle peel the soldered joint apart - they are very weak in this mode. If this is the case, having 2 is of little help as they are both peeling simultaneously, although one end of the rail may move less than the other.

Julian, I think rail length will always be a compromise. Every joint is a potential derailment and a place that needs careful alignment during tracklaying if you're not to get a series of dog-legs, so long lengths are desirable but bad for the mechanical resilience which would be very happy with pre-group 30ft panels.

DaveB

Julian Roberts
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Re: Turnout construction - Question here please.

Postby Julian Roberts » Mon Dec 21, 2020 3:34 pm

Hi Martin

Thanks for posting the drawing and for your earlier reply.

Regarding the point rail railhead, sorry, to ask this but I need help from engineer folks seeing and understanding what the drawing is saying. It looks to me as though the rail is bent at the distance x according to the angle and then the railhead machined equally both sides. Thus is there a slight angle created at the point bend x on the running side of the rail, which would result in the distance from there to the tip gradually widening to the gauge...? - as my earlier drawing suggested. Or is the running line straight at the point bend x on the running side (which is what I'd have expected)? Below I have drawn the running line from the right to left, I think staying with the line as it is to the right of the point bend.

Obtuse point rail drawing with markings.jpg


Jol Wilkinson wrote:When I built the 11 foot extension to the layout I used etched fishplate that incorporated a tag to take a wire dropper. giving a more robust mechanical attachment. I think they were Masokits, but Eileens Emporium also supply a similar Bill Bedford item.

Jol


Hi Jol

A few posts ago I showed a screenshot of the Masokits catalogue showing this. The catalogue is at https://traders.scalefour.org/masokits/

davebradwell wrote:
Julian, I think rail length will always be a compromise. Every joint is a potential derailment and a place that needs careful alignment during tracklaying if you're not to get a series of dog-legs, so long lengths are desirable but bad for the mechanical resilience which would be very happy with pre-group 30ft panels.

DaveB


Hi Dave

Thanks for the warning. While nearly all the track is curved, fortunately there is only one curve on the layout that merits 26 sleepers per panel, the rest is 25 - can't find now what that equates to in actual radius.

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David Thorpe
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Re: Turnout construction - Question here please.

Postby David Thorpe » Mon Dec 21, 2020 4:39 pm

Terry Bendall wrote:
David Thorpe wrote:As far as I know the Exactoscale range of point kits is not currently available.


They are not listed in the Stores list but my understanding is that they are still available to order. Some were on sale I think at Scaleforum 2019 and there may be some still in stock.


There's no mention of them on the rather sparse Exactscale website, and only the track bases are available through the stores. If none have been observed since 2019, I can only think that they are currently unavailable. As I see it, that means that the only range of P4 point kits (and it's a very wide range) is from C&L but they come at a hefty price (£57 + £10 p&p for a basic turnout). As there is surely nothing more important in P4 than the basic track, and as the perceived difficulty of making track appears to be one of the major deterrants to people considering moving to P4, it does seem unfortunate that we now appear to be reliant on one company selling at a premium price. Yet another reason for an approach to be made to Wayne Kinney?

DT

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grovenor-2685
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Re: Turnout construction - Question here please.

Postby grovenor-2685 » Mon Dec 21, 2020 6:54 pm

Julian Roberts wrote:Regarding the point rail railhead, sorry, to ask this but I need help from engineer folks seeing and understanding what the drawing is saying. It looks to me as though the rail is bent at the distance x according to the angle and then the railhead machined equally both sides. Thus is there a slight angle created at the point bend x on the running side of the rail, which would result in the distance from there to the tip gradually widening to the gauge...?

The angle of the bend at point X has to be just enough that the running edge of the rail ends up straight after planing.
Or is the running line straight at the point bend x on the running side (which is what I'd have expected)?
Yes, just so.
If you draw the rail without the bend, then draw on the head taper, the angle between the full rail edge and the planed edge at point X will give you the angle of bend required. Should be half the crossing angle (in degrees). The angle between the two planed edges equals the crossing angle.
Regards
Keith
Grovenor Sidings

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Jol Wilkinson
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Re: Turnout construction - Question here please.

Postby Jol Wilkinson » Mon Dec 21, 2020 7:23 pm

Julian,

thanks, but I already have the current Masokits catalogue downloaded on my pc, together with two older versions.

When I built the extension to London Road I started with Colin Waite etched fishplates (no longer available). These are held together by a small strip which forms a loop under the rail when they are fitted in place, through which the dropper can be connected.. When I ran out of these I bought Masokits 11.31 Folding Connection Fishplates. These have a small tag which provides a location for the dropper (unlike item 11.13 Bullhead Fishplates).

The droppers on the original part of London Road were connected to a solder tag, fixed to the baseboard with a screw. On the extension section I soldered the dropper to a piece of pcb glued to the baseboard, making sure that the dropper wire wasn't tight to avoid putting any stress on it.

Jol

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Martin Wynne
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Re: Turnout construction - Question here please.

Postby Martin Wynne » Mon Dec 21, 2020 8:13 pm

Julian Roberts wrote:It looks to me as though the rail is bent at the distance x according to the angle and then the railhead machined

Hi Julian,

Yes, all switch blades, point rails, vee nose rails, etc., are machined the same way like that. They are machined on both sides, so that there is still solid web metal at the tip to support the head. A set (bend) is then put in the rail where the machining runs out, to return the running edge to dead straight*:

Image

Whether the bend is made before or after the machining depends on the practice in the relevant p.w. workshop, but the result is always that the running edge is dead straight* (not as you have drawn it).

After machining and bending to the required angles, the running edge is then rounded to match the 1/2" top corner radius on the rail section.

*or in the case of some curved switch designs, such as old-type GWR switches, and later types of the BS-113 inclined FB switches, the switch curve through the planing is tangential with the switch radius beyond. More modern FB switches have a more complex transition curve through the switch planing. Likewise the vee nose on some curved crossings may have a radius machined along the nose. But in all cases the machined running edge ends up tangential with the unmachined rail beyond it (not as you have drawn it).

cheers,

Martin.
40+ years developing Templot. And counting ...

Paul Cram
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Re: Turnout construction - Question here please.

Postby Paul Cram » Mon Dec 21, 2020 9:05 pm

davebradwell wrote:Well, Paul Cram, I've made crossings up into soldered units by various means but was never convinced that tolerances of a few thou' could be met by sticking flexible plastic chairs round something to hold it. The position could also be easily influenced by the tracks leading off so I felt critical areas needed soldering. I have a couple of single slips and a C8 that are all glued and they work but the bumps and rattles suggest that the stock is pushing the rails into the correct position. Why do we start track laying with the main-line?

Terry, the dropper you described is exactly the type that's given me so much trouble. I suspect that tiny movements of the rail during the daily temperature cycle peel the soldered joint apart - they are very weak in this mode. If this is the case, having 2 is of little help as they are both peeling simultaneously, although one end of the rail may move less than the other.

Julian, I think rail length will always be a compromise. Every joint is a potential derailment and a place that needs careful alignment during tracklaying if you're not to get a series of dog-legs, so long lengths are desirable but bad for the mechanical resilience which would be very happy with pre-group 30ft panels.

DaveB

The soldered parts were glued using 24 hr epoxy not just held by the chairs, sorry I didn;t make this clerarer

Terry Bendall
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Re: Turnout construction - Question here please.

Postby Terry Bendall » Tue Dec 22, 2020 9:29 am

Jol Wilkinson wrote:that method of attaching droppers was used on the original London Road, built in the mid 1980's. When I bought and "resurrected" the layout, exhibiting it from 2008 we found that the droppers developed dry joints under the rail


Obviously these things can happen. I have used the method on all the layouts i have built since 2000 and so far no problems with droppers developing dry joints. There are of course lots of variables and in the end we all use what we find works best for each of us.

David Thorpe wrote:There's no mention of them on the rather sparse Exactscale website, and only the track bases are available through the stores. If none have been observed since 2019, I can only think that they are currently unavailable.


I believe that those who were involved in resurrecting the Exactoscale turnout kits do at least look at this forum, even if they may not often post any comments. Perhaps one of these people, or someone who knows them might put up something. :thumb

David Thorpe wrote:the only range of P4 point kits (and it's a very wide range) is from C&L but they come at a hefty price (£57 + £10 p&p for a basic turnout).


It is likely that if the Exactoscale turnout kits are available, the price will be similar. Regrettably anyone who wants the convenience, quality and time saved by using a kit has to be prepared to pay for it. Doing it yourself saves a lot of money. :) You also develop skills which can be applied to other aspects of our model making and sometimes it is even enjoyable. :D

Terry Bendall

Philip Hall
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Re: Turnout construction - Question here please.

Postby Philip Hall » Tue Dec 22, 2020 10:02 am

Regarding corrosion of soldered joints, I have been making PCB sleepered track for hidden areas recently using nickel silver rail and paste flux (La-Co or Powerflow). I thought I washed them off but have already seen areas of green powder on the sides of the rails.

I have also been experiencing breathing problems, which I had years back when I first experimented with Powerflow flux. Probably doing forty joints in quick succession didn’t help. So I have now gone back to phosphoric acid, an extractor fan (old paint spraying one) and a small fan. Hopefully it will be healthier and things won’t turn green!

Philip

Julian Roberts
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Re: Turnout construction - Question here please.

Postby Julian Roberts » Tue Dec 22, 2020 12:58 pm

Very many thanks Martin and Keith for your replies, for correcting and amply clarifying that misunderstanding of mine.

Regarding the discussion about kits etc, it seems to me the joy of P4 is not being locked into a Peco geometry mindset, and that it is no more difficult to make pointwork on a curve than straight, thus in combination with the amazing tool that is Templot, real prototype trackwork as it flows and fits into the locality can be modelled exactly. Really it is as simple to make a turnout as plain track, apart from the switches and crossings which can be bought if need be.

Making pointwork on copperclad is dead simple, if you're happy with no vertical space between rail and sleeper. The Masokits system of realistic chairs is quite involved and time consuming, but makes very realistic and robust trackwork. If there was an easy way to give that vertical gap consistently, on a larger layout than my project I'd be tempted to represent the chair with a blob of solder. I may experiment with alternating plastic and soldered chairs on a very long turnout still to be made.

Tony Wilkins
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Re: Turnout construction - Question here please.

Postby Tony Wilkins » Tue Dec 22, 2020 2:11 pm

For droppers I have for years used 22 gauge tinned copper wire soldered to the underside of the rail two per length and not always at opposite ends. The top 3mm or so is bent at right angles to give a decent bond length with the rail and the hole through the baseboard is 1 mm to 1/16th" to give some room for movement. The underside is soldered to tag strips, but leave a bit of slack in the wire so it is not under tension. I always use a rosin type flux such as Carr's Orange label as this is similar to the flux contained in multi-core solder for electrical work where often it is not possible to clean off the flux after soldering. If desired it can be rinsed off using Meths. For joining Copper and Nickel Silver this should be more than adequate. Acid fluxes in my experience always leave minute traces and these continue to react with metals producing corrosion. John Hayes, a well regarded loco builder among his many other talents, used to wash off as much of the flux as he could from the latest etched kit he was building and then leave it in the rain water butt overnight before carrying on with it the next day. I don't recommend this with track. Whatever flux is used, adequate ventilation is highly desirable.

Do I have joint failures? Yes occasionally, but most commonly after testing a baseboard I have just wired with droppers. This is down to poorly soldered joints due to the solder not adequately flowing into the joint, which in some situations can be difficult to get the soldering iron bit into good contacted with the attempted joint. Also one cannot see just how clean the underside of the rail is, dried PVA glue being an effective solder mask. Soldering the dropper to the side of the rail will probably be more reliable long term as the bond area will be greater, due to it sitting in the web and it is easier to inspect visibly, but that is also its down side.

I remember when helping to dismantle Heckmondwike discovering that most of the rails were held in place by the remaining Evostuck whitemetal chairs and the dropper wires, the solder joints between the tinned steel rivets and the n/s rail having long since failed.

Regards
Tony.
Inspiration from the past. Dreams for the future.

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Martin Wynne
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Re: Turnout construction - Question here please.

Postby Martin Wynne » Tue Dec 22, 2020 2:48 pm

Julian Roberts wrote:If there was an easy way to give that vertical gap consistently, on a larger layout than my project I'd be tempted to represent the chair with a blob of solder.

Hi Julian,

On copper-clad it's easy -- 1mm drill in a Dremel mini-drill, push in a Vero pin. Lifts the rail the right amount, and on copper-clad allows a nice solder fillet to represent the chairs.

Trim the underside with flush snips, and on double-sided copper-clad remember to gap the bottom side too. Or if unsnipped they make it easy to attach an invisible dropper.

Alternatively the head of a Vero pin is smaller than a Brook Smith rivet, so easier to fit cosmetic plastic chairs. In which case use a thin smear of solder cream (2% silver SMT paste) for the rail rather than a full fillet of solder.

Image

Unfortunately Vero pins won't hold in the 0.8mm ply timbers, but they might in thicker timbers, such as 4mm wide limewood strip from model boat building suppliers.

More about using Vero pins: https://85a.co.uk/forum/view_topic.php? ... e=2#p21435

Martin.
40+ years developing Templot. And counting ...

davebradwell
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Re: Turnout construction - Question here please.

Postby davebradwell » Tue Dec 22, 2020 8:04 pm

Tony, this dropper business must be down to environmental matters - mine were all done exactly as you describe following good electrical standards with rosin flux, loops in the wire, etc, etc but the building was left unheated out of hours back then and result was a high level of failures. Building now has at least some background heat....which could do with turning up. Your bulding looks very posh but well worthwhile considering the investment it contains.

Anybody that uses plumbers flux on electrical work almost deserves problems! It's common to use Powerflow flux on trackwork but it has to be scrubbed off with copious quantities of water - I know someone who uses the shower tray for lumps of complex pointwork. You can't do this with the layout so it has to be rosin, or cored solder for electrical stuff. There's probably a modern equivalent.

DaveB

JFS
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Re: Turnout construction - Question here please.

Postby JFS » Tue Dec 22, 2020 8:53 pm

I suspect Tony has as much practical experience as anyone, but I wonder if there is a good reason for using solid tinned-copper wire? Would a multi strand wire not give additional flexibility?

davebradwell wrote: ... the result was a high level of failures.
DaveB


We must both be unlucky Dave - I too had failures with droppers soldered to the underside of the rail on my previous layout.

But it might come down to the detail of the method - if you can solder the droppers to the bottom of the rail whilst you are able to invert it - ie before laying - that is one thing. I was trying to do mine AFTER it had been laid - and without Tony's level of experience! So I put my failures down to the impossibility of cleaning the bottom of the rail.

For my current layout I "built-in" all the droppers as part of construction. And still had one or two of them fail.

The first P4 layout I was involved with 60 years ago, we used the Studiolith "Turnout Bonding Strip" - self adhesive copper foil stuck to the sleeper top that the (tinned steel) rivets were rivetted into and then soldered up when the rail was fixed. Completely invisible; built like a tank - perfect. One by one they all failed - mostly due to the tinning coming off the rivet head - a la Heckmondwyke. Worst thing was, they looked perfectly sound to the naked eye! Studiolith also did a "Wiring connector strip" - punched brass strip intended to be rivetted to the unerside of the timber and buried in the ballast. What could possibly go wrong with that? I suspect that Martin's vero pin "modern equivalent" is much more robust, but I still hesitate at using a common solution which both fixes the rail AND provides an electrical feed.

I, like most people, build-in some redundancy by fitting more than one jumper to each bit of rail. The only problem is, when you load up your layout to travel to an exhibition it will be working perfectly with 2 out of three droppers failed. By the time it is set-up however ... ... and I know of no way of testing them! Perhaps the answer is to FIT three droppers, but only wire ONE of them.


Best Wishes,
Howard

Tony Wilkins
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Re: Turnout construction - Question here please.

Postby Tony Wilkins » Tue Dec 22, 2020 10:02 pm

Hi Dave.
I am sure you are correct that environmental factors play a part. Thermal cycling being the main one, the greater the temperature range obviously the greater the effect, but humidity can also play a part with damp conditions accelerating any corrosion effects and in severe cases even allowing electrolytic corrosion to take place although things would have to be pretty bad for that to occur. The shed where Heckmondwike was kept had some background heat on a thermostat maintained at about 8 C from memory being then warmed up for meetings. When it went to York it was in an even better controlled environment so this probably helped. The rivet rot would have been well under way before then though. Eames fluid was used by more than one track builder back then. There is perhaps a further factor. N/S, copper and solder all have different rates of expansion but are in solid contact even if over a short distance. I have experienced failed solder joints on PCBs where there has been movement over time producing hairline cracks, thermal cycling being the most likely cause.

Howard.
I use solid tinned copper wire because I always have, it seemed to work, was relatively cheap and solders well being effectively pre tinned.
A lecture I attended some years ago about electrics and layouts the speaker recommended multi strand wire for flexibility. The flaw with that idea is that when you pre tin the strands, the solder flows down the strands and effectively fuses the whole thing solid even within the insulation for a little way, so you end up with solid core wire anyway at the ends. There is also less risk of stay strands causing unwanted shorts.

Studiolith eventually issued a warning not to use the Wiring Connector Strip precisely because it was found to fail, but by then I wonder how many layouts had used it.
Regards
Tony.
Inspiration from the past. Dreams for the future.

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David Thorpe
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Re: Turnout construction - Question here please.

Postby David Thorpe » Wed Dec 23, 2020 12:06 am

I've very pleased to say that, without any consultation with Tony, I use virtually the same method as he does for soldering dropper wires to the undersides of rails. The only real difference is that I have used multistrand copper wire, but as Tony says that is effectively fused solid when the solder flows down the strands. I'm not a bad solderer, I use Carrs Green Label flux usually with cored electrical solder wire, and I always make sure with a quick tug on the wire that it is securely attached - the 3mm bent over section at the top bonds securely with the rail. To date I have had very few failures, but there again the room in which my layout is kept also contains the central heating boiler so it never gets cold or damp and the layout itself is not portable.

DT

Paul Cram
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Re: Turnout construction - Bullhead rail.

Postby Paul Cram » Fri Dec 25, 2020 12:20 pm

hi Tony
How have you dealt with the tiebars for the double slip?

Tony Wilkins
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Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sat Dec 26, 2020 5:19 pm

Paul Cram wrote:hi Tony
How have you dealt with the tiebars for the double slip?


Hi Paul.
The operation of double slips on my current project Brimsdown was covered starting here viewtopic.php?f=9&t=5707&start=350#p76565 , but as these are in the storage sidings (fiddle yard) they don't have tie bars. On my previous layout Green Street and some other layouts I have been closely involved with they have used a somewhat impressionistic cosmetic arrangement that has no moving parts and does not contact the rails to avoid the possibility of shorts.
Regards
Tony.
Inspiration from the past. Dreams for the future.

Paul Cram
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Re: Turnout construction - Bullhead rail.

Postby Paul Cram » Sun Dec 27, 2020 8:47 pm

Tony Wilkins wrote:
Paul Cram wrote:hi Tony
How have you dealt with the tiebars for the double slip?


Hi Paul.
The operation of double slips on my current project Brimsdown was covered starting here viewtopic.php?f=9&t=5707&start=350#p76565 , but as these are in the storage sidings (fiddle yard) they don't have tie bars. On my previous layout Green Street and some other layouts I have been closely involved with they have used a somewhat impressionistic cosmetic arrangement that has no moving parts and does not contact the rails to avoid the possibility of shorts.
Regards
Tony.

Thanks for the eply. How have you arranged the movement of the switches so that both sets move together or don't they?

Tony Wilkins
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Re: Turnout construction - Bullhead rail.

Postby Tony Wilkins » Sun Dec 27, 2020 11:56 pm

Paul Cram wrote:
Tony Wilkins wrote:
Paul Cram wrote:hi Tony
How have you dealt with the tiebars for the double slip?


Hi Paul.
The operation of double slips on my current project Brimsdown was covered starting here viewtopic.php?f=9&t=5707&start=350#p76565 , but as these are in the storage sidings (fiddle yard) they don't have tie bars. On my previous layout Green Street and some other layouts I have been closely involved with they have used a somewhat impressionistic cosmetic arrangement that has no moving parts and does not contact the rails to avoid the possibility of shorts.
Regards
Tony.

Thanks for the reply. How have you arranged the movement of the switches so that both sets move together or don't they?

Hi Paul.
If you scroll down the page far enough from the link you will see that all four blades at one end are driven in unison from the same slide bar underneath by one point motor.

Regards
Tony.
Inspiration from the past. Dreams for the future.

Paul Cram
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Re: Turnout construction - Question here please.

Postby Paul Cram » Mon Dec 28, 2020 9:05 pm

Thanks Tony very helpful.


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