Turnout Construction - a summary of what I've learned from the Forum and Templot

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Julian Roberts
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Joined: Sat Jan 09, 2010 11:33 pm

Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Julian Roberts » Tue Mar 23, 2021 8:19 am

I started making P4 turnouts about 6 years ago. Since then I've learned a huge amount from this Forum and the Templot Forum, and particularly from the Templot "Real Track", now at https://85a.uk/templot/companion/real_track.php

I've summarized it recently. I've written it as though I was speaking to myself as I was six years ago, trying to explain it in logical steps. Some bits I've inferred, some bits I may have mis-remembered, quite a bit of the crossing section is my own invention.

It's a work in progress, and really needs shortening - but I may not get round to finishing it properly and I'm putting it here in case I don't. Do feel free to suggest corrections or make criticisms!

Edit. I've changed the beginning to clarify that much of this is drawn from Tony Wilkins and Martin Wynne, and their articles etc are the authoritative ones.

Re-edit 27 April: I've simplified and hopefully clarified the "Undercut Blades" section. The first version was downloaded about 60 times, the second about 30 times.

The page numbers below now may be slightly inaccurate

Intro 1 - 9
Switch:
Stockgauge 10 - 12
Undercut blades 13 - 28
Joggled switch 29 - 36
Crossing:
Common Crossing 37 - 45
Check rails and stock rails 45 - 50
Appendix 50 -55
Attachments
SWITCH AND CROSSING REVISED 27 APRIL 2021 NEAT COPY OF EDITING HELP.pdf
(7.38 MiB) Downloaded 35 times
Last edited by Julian Roberts on Tue Apr 27, 2021 6:51 pm, edited 4 times in total.

Daddyman
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Joined: Sat Jun 03, 2017 1:09 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Daddyman » Tue Mar 23, 2021 11:38 am

Many thanks for this. I've glanced through the first 6 pages and it looks like it could be very useful. I haven't spotted a single error in English in those 6 pages either, which is always nice...

PhilipT
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Joined: Thu Mar 05, 2015 4:18 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby PhilipT » Tue Mar 23, 2021 8:05 pm

Very useful stuff, Julian!

I'm in complete agreement about the 1 in 5 vertical taper at the ends of switchblades and also the slight reduction in rail height towards the tips of the blades. This is one of the most important things I have learned in the past few years and it makes sure that the wheel is gently guided onto the blade as there is no sharp bit of rail to get in the way of the wheel.

I also found from studying "Standard Railway Equipment - Permanent Way,1926" (lots of drawings of PW items - obtainable from the North Eastern Railway Association) that similarly in the prototype, a height reduction is also made at the point of the vee. I assume that this is to account for the 1 in 20 wheel coning causing the wheel edge to drop slightly as it leaves the support of the wing rail - without the height reduction, the wheel would jolt as it hit the vee. I therefore put a slight downwards taper on my vees along with slightly blunting the tip.

Phil Tattershall

jasp
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Joined: Thu Dec 04, 2008 9:24 am

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby jasp » Tue Mar 23, 2021 8:10 pm

Julian
Well done, a masterful treatise, thank you.
The double junction awaits!
Jim P

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grovenor-2685
Forum Team
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Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby grovenor-2685 » Tue Mar 23, 2021 8:45 pm

Seems like the ideal candidate for an entry in the "Notes" section.
Regards
Keith
Grovenor Sidings

Tony Wilkins
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Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Tony Wilkins » Tue Mar 23, 2021 10:09 pm

PhilipT wrote:Very useful stuff, Julian!

I'm in complete agreement about the 1 in 5 vertical taper at the ends of switchblades and also the slight reduction in rail height towards the tips of the blades. This is one of the most important things I have learned in the past few years and it makes sure that the wheel is gently guided onto the blade as there is no sharp bit of rail to get in the way of the wheel.

I also found from studying "Standard Railway Equipment - Permanent Way,1926" (lots of drawings of PW items - obtainable from the North Eastern Railway Association) that similarly in the prototype, a height reduction is also made at the point of the vee. I assume that this is to account for the 1 in 20 wheel coning causing the wheel edge to drop slightly as it leaves the support of the wing rail - without the height reduction, the wheel would jolt as it hit the vee. I therefore put a slight downwards taper on my vees along with slightly blunting the tip.

Phil Tattershall


Hi Phil.
Both are explained in my Bullhead Turnout construction thread and yes you are correct about the reason for the vertical taper of the crossing vee nose. The difference, if you don't do so, can be felt even at our scale.

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

Winander
Posts: 283
Joined: Thu Mar 20, 2014 12:19 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Winander » Wed Mar 24, 2021 12:44 pm

Julian,

Regarding the question you posed in the document about the width of the switch rail at the tip. In this post https://www.scalefour.org/forum/viewtopic.php?f=5&t=5727#p58886 Tony Wilkins advises when filing the running face
With Steel rail as soon as the cut reaches the web as here, stop filing. Nickel Silver rail can take a bit more than this, but I have found that with the Steel rail if it gets too thin the end of the rail can suddenly buckle ruining the work you have just done.

I haven't checked the questions thread.

IIRC Howard Bolton (who, unlike Tony, did not use a society filing jig) advised to file the stock rail side half way through the web and on the running face remove the head, but because our model rail has an overscale web, some of that should be removed too.

---------------
The vertical planing of the top edge of the switch occurs before the 1 in 5 (12 degree) planing of the running face. My impression is you have advised the opposite sequence. I also don't believe you have mentioned the need to bend the rail after the initial filing to transfer the angle from the stock side to the running side. If you have, it needs to be earlier in the document.

The combination of the vertical and angled planing means the tip of the switch at its base can be wider than the allowance provided by the set in the stock rail - the thickest part is well below the rail top as shown in your 'model version of undercut switch tip' diagram. So the switch tip may be more than your calculated 0.03mm wide. The combined planing is designed to interact with the flange to guide the wheel to the diverging route and the switch will only bear the full weight of the wheel at the end of the planing where it has a full profile - I think you described that much later although your descriptions of wear on prototypes did confuse me.
Richard Hodgson

Tony Wilkins
Posts: 552
Joined: Tue Mar 20, 2012 3:57 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Tony Wilkins » Wed Mar 24, 2021 1:20 pm

Winander wrote:Julian,

Regarding the question you posed in the document about the width of the switch rail at the tip. In this post https://www.scalefour.org/forum/viewtopic.php?f=5&t=5727#p58886 Tony Wilkins advises when filing the running face
With Steel rail as soon as the cut reaches the web as here, stop filing. Nickel Silver rail can take a bit more than this, but I have found that with the Steel rail if it gets too thin the end of the rail can suddenly buckle ruining the work you have just done.

I haven't checked the questions thread.

IIRC Howard Bolton (who, unlike Tony, did not use a society filing jig) advised to file the stock rail side half way through the web and on the running face remove the head, but because our model rail has an overscale web, some of that should be removed too.

---------------
The vertical planing of the top edge of the switch occurs before the 1 in 5 (12 degree) planing of the running face. My impression is you have advised the opposite sequence. I also don't believe you have mentioned the need to bend the rail after the initial filing to transfer the angle from the stock side to the running side. If you have, it needs to be earlier in the document.

The combination of the vertical and angled planing means the tip of the switch at its base can be wider than the allowance provided by the set in the stock rail - the thickest part is well below the rail top as shown in your 'model version of undercut switch tip' diagram. So the switch tip may be more than your calculated 0.03mm wide. The combined planing is designed to interact with the flange to guide the wheel to the diverging route and the switch will only bear the full weight of the wheel at the end of the planing where it has a full profile - I think you described that much later although your descriptions of wear on prototypes did confuse me.

Regarding my quote, I have already removed half the thickness of the rail (into the web) from the inside face before filing down the back to achieve the desired thickness. I think Howard files down the back first.
Regards
Tony.
Inspiration from the past. Dreams for the future.

Julian Roberts
Posts: 1016
Joined: Sat Jan 09, 2010 11:33 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Julian Roberts » Wed Mar 24, 2021 2:39 pm

Thanks for feedback everyone. I've edited the first post and attached an updated download. Apologies that the whole thing is not really absolutely finished. It is not in any way meant to supplant or change anything that Tony and Martin have written. It is drawn from them but as you say Richard may miss out essential things. I have clarified this in the script in two places, that they are the authoritative sources. I have added this:

UNDERCUT BLADE SWITCH. THE BLADES – HOW THIN?
The following is mostly drawn from Tony Wilkins’ account at viewtopic.php?f=5&t=5727#p58886
and should not contradict that in any respect. If it does, this is not intentional. Please read that in addition to the below as there may be essential aspects that I have not described. Remember, this is not meant to be a guide to making turnouts, rather to highlight some aspects that I did not fully understand.

Thank you for showing what I could improve, and I will do this ASAP.

Edit I've now clarified that the railfoot of the switch blade is left fully half-width at the tip - obviously a crucial thing to understand.

Winander
Posts: 283
Joined: Thu Mar 20, 2014 12:19 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Winander » Wed Mar 24, 2021 5:10 pm

Tony Wilkins wrote:Regarding my quote, I have already removed half the thickness of the rail (into the web) from the inside face before filing down the back to achieve the desired thickness. I think Howard files down the back first.
Regards
Tony.


Tony,

Apologies, I had that in once and it got unintentionally edited out (that sounds like an oxymoron) probably when removing references to your use of a jig.
Richard Hodgson

Julian Roberts
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Joined: Sat Jan 09, 2010 11:33 pm

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Julian Roberts » Thu Apr 29, 2021 1:11 pm

I've edited the download attached to the opening post. The undercut blades section I hope now reads more clearly and simply.

Apologies I am still not replying properly to Richard's points (simply shortage of time) but hopefully the document does. It is still a work in progress however.

Regarding the order of procedure, it was Templot suggesting filing the stockrail side of the blade first that is the reason I do, also not possessing any blade filing jig.

Carlos
Posts: 41
Joined: Mon Jul 21, 2008 6:38 am

Re: Turnout Construction - a summary of what I've learned from the Forum and Templot

Postby Carlos » Thu Apr 29, 2021 7:11 pm

Thanks Julian, I found the first version very useful.


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