Templot Club Archive 2007-2020
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posted: 5 May 2017 13:04 from: Richard Lambert click the date to link to this post click member name to view archived images |
Hi, Many moons ago, I rocked the established O gauge boat and started building to and promoting 31.5mm trackwork - matching the track to the de facto wheel standards. I now find myself in exactly the same position in G1. The crossing noses on the 'standard' standard track take an almighty battering, especially considering the weight and speed of the locos in particular. I wonder whether there is scope to tighten up the trackwork through the turnouts in particular, and wish to take advantage of the expertise in this group to consider same. The issue is in fact exactly the same. The wheels are thus. Now given that, what should the track work standards be. Wheel Standards: Back to back: 40mm Wheel width: 6mm Flange width: 1.5mm Tread: 4.5mm Back to back plus flange: 41.5mm The current track standard has: Gauge: 45mm Flangeway: 3mm Check gauge: 42mm What should the track standards be given the wheel standard as set out? Thank you for your assistance. Richard Lambert |
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posted: 5 May 2017 13:59 from: Ian Allen
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Richard, Have you looked at the data for 1F on Templot ? Gauge: 45.0mm Flangeway gap: 1.75mm However, that would equate to 41.5mm across check rails so you'd still need to lose 1.75mm to 2mm. I'd be tempted to drop your gauge down to 43mm if using a 1.75mm flangeway, or if you go to 2mm, you could have a gauge of 43.5mm. Both options would help with the crossing nose to wing rail gap. Ian |
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posted: 6 May 2017 13:25 from: Martin Wynne
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Richard Lambert wrote: The crossing noses on the 'standard' standard track take an almighty battering... ...The wheels are thus. Now given that, what should the track work standards be?Hi Richard, The crossing noses are taking a battering, because like most of the "traditional" model railway standards, no allowance has been made for a blunt nose on the vee. And in order for the wheels to be fully supported (and in this case only barely so), the nose must be made dead sharp. I have no practical experience of Gauge 1, so this below is based purely on the dimensions you gave.  I suggest going back to basics and deriving the track from the actual wheels. We start with the magic fraction of 9/14ths. Which is the optimum ratio between flange thickness and flangeway gap. So with a flange thickness of 1.5mm that means a flangeway gap of 1.5 x 14 / 9 = 2.33mm. It's silly to go to a second decimal place in the larger scales, so I suggest a crossing flangeway gap of 2.3mm. That needs to be a MAX to calculate the minimum wheel width and ensure full wheel support through the crossing. The prototype blunt nose width is 3/4" (bullhead, not GWR). The scale for Gauge 1 seems to be a bit variable, so let's say that is 0.6mm MAX blunt nose width. That should be wide enough to take a bit of abuse from heavy locomotives, especially if you adopt the prototype practice of taking the top of it down below the height of the wing rails, to allow for the coning angle on the wheel tread. We can now calculate the minimum wheel width, which is 2 x max flangeway gap, + max blunt nose, + a bit to ensure good support through the crossing. So that's 2 x 2.3 , + 0.6 = 5.2 . Plus a bit = 5.5mm MIN wheel width. Assuming wheels have been set to 40mm back-to-back nominal, this is likely to vary a bit on existing models. And some wheels may have a flange thickness a bit more than 1.5mm. So let's make the back-to-flange dimension 41.7mm MAX. It is essential that this should be a MAX. This dimension also becomes the minimum check gauge, and adding the flangeway gap gives us the minimum track gauge. So track gauge = 41.7m + 2.3 = 44.0mm MIN. And the check span is 41.7mm - 2.3mm = 39.4. Plus some freedom in the tolerancing = 39.5mm MAX. Then choose a flange curving allowance, for which I suggest 0.3mm. So that finally gives a minimum back-to-back of 39.5 + 0.3 = 39.8mm. MIN. Summarising all that, I suggest: WHEELS: Wheel Width 5.5mm MIN. Flange Thickness 1.9mm MAX. Back-to-Flange: 41.7mm MAX. This is the most critical dimension. Back-to-Back: 39.8mm MIN. It is important to understand there is no maximum back-to-back dimension, the maximum wheel spacing on the axle is set by the Back-to-Flange dimension. For the best running aim to get as close to this as possible (without ever exceeding it), rather than the minimum back-to-back dimension. Taking the flange thickness up to the 1.9mm maximum would obviously require setting the minimum 39.8mm back-to-back to avoid exceeding the 41.7mm back-to-flange. TRACK: Track Gauge: 44.0mm MIN. Check Gauge: 41.7mm MIN. This is the most critical dimension. Crossing Flangeway: 2.3mm MAX. Blunt Nose: 0.6mm MAX. Check Span: 39.5mm MAX. Just to repeat this is all theory, I haven't actually tried it. regards, Martin. |
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posted: 6 May 2017 15:48 from: Richard Lambert click the date to link to this post click member name to view archived images |
Hi Martin, Thanks so much for that, it's exactly what I wanted. I do appreciate it's theoretical (at least until I build one), but seeing how successful 31.5mm has been in 7mm, I was sure something could be done that would improve both looks and running for 'standard' G1. Now, how to get across the concept to G1MRA, hmmmm. Richard |
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posted: 6 May 2017 17:05 from: Martin Wynne
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Richard Lambert wrote:Now, how to get across the concept to G1MRA, hmmmm.Hi Richard, Which prompted me to go and look at their standards: http://www.g1mra.com/pdf/standard-dimensions-for-gauge1.pdf I see that some existing wheels may have a back-to-flange dimension up to 42.0mm (you did not mention that  ).Such wheels would not run very well on the dimensions I posted earlier. Also the 40mm back-to-back is in fact the quoted minimum. In which case most wheels would presumably be wider. So increasing the check gauge to 42.0mm we get: WHEELS: Wheel Width 5.5mm MIN. Flange Thickness 2.0mm MAX. (with back-to-back on minimum). Back-to-Flange: 42.0mm MAX. This is the most critical dimension. Back-to-Back: 40.0mm MIN. TRACK: Track Gauge: 44.3mm MIN. Check Gauge: 42.0mm MIN. This is the most critical dimension. Also no change from the existing standard, for maximum compatibility. Crossing Flangeway: 2.3mm MAX. Blunt Nose: 0.6mm MAX. Check Span: 39.8mm MAX. Which may work better with a mixture of existing wheels. But loses the convenience of a round figure for the track gauge. regards, Martin. |
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posted: 6 May 2017 17:16 from: Richard Lambert click the date to link to this post click member name to view archived images |
Hi Martin, The figures I gave you (just like the Slater's wheels in 7mm scale) were taken from the wheels in my possession covering all the manufacturers I am likely to run. They are what they are, irrespective of what G1MRA may say, so your original figures are sound for my purposes. The figures I quoted suit Aster, Marklin, Kiss, KM1, Hubner, Finescale Brass, J&M. I shall build a turnout to your initial suggestions and report back! Yours, Richard Edit: I realise now having looked at the G1MRA standards, that I hadn't looked at the +/- column, so I see where you are coming from. I shall measure some of my wheels to see exactly how well they fit the parameters, particularly the BEF. R |
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| Last edited on posted: 6 May 2017 17:26 by Richard Lambert |
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6 May 2017 17:26 from: Martin Wynne
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Richard Lambert wrote: The figures I quoted suit Aster, Marklin, Kiss, KM1, Hubner, Finescale Brass, J&M. I shall build a turnout to your initial suggestions and report back!Hi Richard, OK. You know what you are doing. When the fireworks begin with G1MRA, I shall watch from afar with interest! IMPORTANT: Your new standard needs a unique name. This is important so that it can be referred to without confusion. Also so that I can include it in Templot. I suggest 1-MC (modified coarse). regards, Martin. |
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posted: 8 May 2017 07:59 from: Terry Flynn
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Richard Lambert wrote: Hi,Hello Richard, The answer depends on what tolerances are on your wheel specification and to what accuracy you can make track to. The AMRA fine tolerance standard suits the wheels you are using. http://amra.asn.au/wp-content/uploads/sites/7/2016/03/finewheeltrack.pdf The recommended dimensions from the AMRA fine tolerance standard for 1 gauge crossings are; Track gauge 14.4mm to 14.5mm Track flangeway 2.5mm to 2.6mm This gives a check gauge of 41.8mm This gives a maximum span of 39.5mm Wheel drop will be minimal as the flangeway is less than double the wheel width. If you try to use a finer track tolerance and maintaining the above check gauge using the same AMRA spread sheet mathematics we get. Track gauge 44.28mm to 44.34mm Track flangeway 2.42mm to 2.48mm This will give less wheel drop, but it will be harder to get within tolerance. Cheers, Terry Flynn. |
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posted: 12 May 2017 14:33 from: Richard Lambert click the date to link to this post click member name to view archived images |
Thank you Terry. I have been further looking at the wheels amongst the group members. The variation, particularly amongst the higher end of the market, Kiss and KM1 was more than I was expecting, and indeed, they were not as fine as the wheels on my own stock. I have had to revise my thinking....and owe Martin an apology along the way as the wheel standard I adopt is likely to be his second set of figures. My Marklin live steam BR44 has BTB 39.8mm and BEF 41.2mm. A Kiss BR 38 (2008 model) has BTB 39.9mm and BEF of 41.2mm A KM1 BR23 (2014 model) has BTB 40.0mm and BEF of 41.8mm An Aster MN has BTB 39.9mm and BEF of 41.8mm Ho hum, more thinking. Richard |
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posted: 12 May 2017 15:07 from: Martin Wynne
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Richard Lambert wrote:My Marklin live steam BR44 has BTB 39.8mm and BEF 41.2mm.Hi Richard, Always the way with a mixed collection of RTR models. Using my second set of figures, the Marklin is likely to bind across the check span at 39.8mm back-to-back. To run all these reliably I think you will need to open things up a bit more. I suggest a flangeway of 2.5mm max, check gauge of 42.0mm min, minimum wheel width 5.75mm. So thirdly: TRACK: Track Gauge: 44.5mm MIN. (see p.s. below) Check Gauge: 42.0mm MIN. This is the most critical dimension. Crossing Flangeway: 2.5mm MAX. Blunt Nose: 0.6mm MAX. Check Span: 39.6mm MAX. WHEELS: Wheel Width 5.75mm MIN. Flange Thickness 2.0mm MAX. Back-to-Flange: 42.0mm MAX. This is the most critical dimension. Back-to-Back: 39.8mm MIN. p.s. You might like to make the flangeway 2.45mm max, in which case the track gauge becomes 44.45mm min. Which just happens to be the traditional Gauge 1 track gauge of 1.3/4". regards, Martin. |
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posted: 13 May 2017 21:57 from: Richard Lambert click the date to link to this post click member name to view archived images |
Thank you Martin. I'm going with the 2.45mm flangeway and 44.45mm gauge....at least that is what the gauges I will be using will be machined to. As for a name for this, how about 'modified standard'? To use coarse to my mind implies it is worse than standard. I will let you know how well it works! Thank you for your assistance. Richard |
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posted: 13 May 2017 22:28 from: Martin Wynne
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Richard Lambert wrote: Thank you Martin. I'm going with the 2.45mm flangeway and 44.45mm gauge....at least that is what the gauges I will be using will be machined toHi Richard, I like it! It's good to retain traditional imperial dimensions when we can. They are always more brain-friendly. 1.3/4" is a nice dimension for us -- it's the prototype flangeway gap. As for a name for this, how about 'modified standard'? To use coarse to my mind implies it is worse than standard.OK, it's your gauge. But currently we don't have a standard called "Standard" in Templot. The 3 existing Gauge 1 pre-sets are called: P-32 ScaleOne32 1C Gauge 1 Coarse 1F Gauge 1 Fine I will add 1-MS (or just 1M ?) in the next program update, but maybe wait until you: I will let you know how well it works!I look forward to your report. regards, Martin. |
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posted: 14 May 2017 23:50 from: Terry Flynn
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Richard Lambert wrote: Thank you Martin. I'm going with the 2.45mm flangeway and 44.45mm gauge....at least that is what the gauges I will be using will be machined to.Hello Richard, All the wheels you have measured so fare are suitable for the AMRA track standard. If you want to use 2.45mm nominal flangeways then I strongly suggest you use the 44.31mm nominal track gauge otherwise you may end up with the back to back of some models binding on the check and wing rails. Personally I would call it 1-SF. Martin, Why no AMRA 1 gauge standrds in Templot ? 44.45mm track gauge, flangeway 2.55mm = AMRA-FT (AMRA fine tolerance) Cheers, Terry Flynn. |
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