Templot Club Archive 2007-2020
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posted: 14 Jul 2017 16:33 from: Dr G Alan Gee
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I model Irish 3ft narrow gauge in 4mm scale on 12mm track. I have used Peco HOm track in the past. peco points are 20 inch (508mm) radius with a V angle of 10 degrees. The distance from the bottom of the V to the tie bar is 105mm. The nearest point to this I have tried to draw with Templot is a B6. this has a similar radius of 566mm but the length from V to tie bar is 134mm and the V angle is larger. My question is why are the Peco points more compact and what do I have to do with Templot to produce something similar ie shorter in length but with a 20 inch radius. | ||
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posted: 14 Jul 2017 17:16 from: stuart1600
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Hello, Alan (since you didn't sign your posting I'm guessing that's appropriate) You've hit on the fundamental difference between Templot and train-set type pointwork - the latter has to be manufactured to a fixed geometry so that individual points, crossings, etc.,. can be interchangeable. Templot draws pointwork templates to prototype practice. The first question would be why do you want to replicate the Peco geometry? Are you planning to handbuild new pointwork to replace existing Peco items, or do you want to use Templot to design a layout that you will build using Peco pointwork? If the latter, then there are probably better programs to suit that purpose (but I am not sufficiently familiar with them to suggest exactly what might suit you best for HOm equivalent templates) If you're planning on hand-building your pointwork then surely you don't need to follow Peco's geometry. Sorry to answer your question with more questions, but as so often happens, to provide any useful guidance requires more information.  Regards, Stuart |
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posted: 14 Jul 2017 18:14 from: stuart1600
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A follow-on from my earlier post.... It occurred to me that if replicating the Peco point is crucial for you, the most important feature is probably the V-crossing angle, so that your replacement turnout will align correctly with other tracks. If you go to template>V-crossing settings and select "other", then enter k10 this tells Templot to create a V-crossing with an angle of 10 degrees. Probably also appropriate to use an A switch; so what you should have now will be an A-5.67 turnout, and the info box tells me this has a turnout radius of 19.4". If, for whatever reason, 20" has some particular importance then you can adjust the radius by altering the length of the entry-straight SHIFT-F11 - if you watch the info box you can see the "smallest radius" changing as you move the mouse. If you really do need exactly 20" (i.e. 19.9 or 20.1 won't do) then you can enter the figure directly in template>V-crossing settings by checking the "fixed at" box in the bottom right corner of that window. I'm far from being an expert on Templot but I think all of the above is correct - someone will step in if I've got something wrong I'm sure. regards, Stuart |
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posted: 14 Jul 2017 18:40 from: Martin Wynne
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Hi Alan, As Stuart explained, Templot isn't really designed to match Peco turnout geometry. However, if you really need to, it can be done. Firstly the 10 degree crossing angle corresponds to 1:5.67 RAM -- not an angle any prototype is likely to use, although I can't speak for Irish narrow gauge.  The B switch is a semi-curved switch in bullhead, again not something to be found on narrow gauge. Ideally you need to create a custom switch from prototype data, but for most narrow gauge and industrial practice you can simply use an existing short straight switch. Here I used the 1:24 short model switch in Templot to get close to the Peco sizes. Then I adjusted the crossing entry straight to match the Peco lead length. This is the result overlaid on the Peco H0m drawing: 2_141329_320000001.png  2_141329_320000000.png  base drawing © Peco The Peco check rails are ludicrously short, and the vee rails look unlikely short to me. So as you can see I have extended them beyond the Peco drawing. The radius comes out at 525mm. I set the rail-head width to 2" (guess) for narrow gauge, and 6ft long 9" wide timbering at 30" centres. .box file attached below. However I really don't suggest you build this. A 1:6 crossing angle would be much more likely and maybe a 9ft switch. Also narrow gauge turnouts often have curviform crossings to save space. I don't know the standards used for 4mm 3ft gauge, so I have guessed 1.0mm crossing flangeway. Note that the flat-bottom rail foot edges show only on background templates and only on the output. Not on the screen or on the control template. regards, Martin. |
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| Attachment: attach_2464_3044_4mm_3ft_for_alan.box 210 | |||
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posted: 15 Jul 2017 12:06 from: Dr G Alan Gee
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Thank you all for your help. The reason for comparison to the Peco HOm switch is that I know a County Donegal Class 5 4-6-2 tank will run perfectly through their points. The Peco HOm points are smaller in length than I have been able to draw previously with Templot and size will be important on the next layout. I shall use code 75 flat bottom rail and copperclad to make the points.CDR sleepers are 6ft 9inch by 10inches x 5 inches. If anybody can suggest a better alterative to the Peco example having a similar length I would gratefully appreciate it. Kind regards Alan |
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posted: 15 Jul 2017 13:37 from: Martin Wynne
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Dr G Alan Gee wrote: If anybody can suggest a better alternative to the Peco example having a similar length I would gratefully appreciate it.Hi Alan, If you are intending to build your pointwork there is no need to have any regard to the Peco sizes or any other ready-made alternatives. All you need to know is that your locomotive will run round 20" curves, and make sure you don't go below that in your designs. In a typical track plan you are likely to need several turnout sizes, from a very short Y-turnout to much longer turnouts where you want them to be curved. I have updated my previous design with your timber sizes. I changed the crossing angle to 1:5 and changed it to curviform pattern for this example. That makes for a typical curvy narrow-gauge crossover. I also shortened the vee rails by one timber, although this doesn't change the geometry. I have set the adjacent track centres for this crossover to 9ft (36mm) although I don't know how typical that would be. It assumes your rolling-stock is no wider than say 7ft-6in? As you can see, the radius is 591mm, well above your limit, but the turnouts are still the same length as the Peco turnout. 2_150818_230000001.png  2_150818_230000000.png  .box file attached below. regards, Martin. |
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| Attachment: attach_2467_3044_irish_4mm3ft_24_5.box 197 | |||
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posted: 15 Jul 2017 14:08 from: Martin Wynne
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p.s. For example, here is a longer curved turnout. 1:32 short switch, 1:8 crossing angle. Curved onto 1000mm outer radius. Inner radius is 604mm: 2_150905_260000000.png  Martin. |
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