Templot Club Archive 2007-2020
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posted: 2 Mar 2012 00:06 from: Ewerthon Mota click the date to link to this post click member name to view archived images |
Someone has some experience with this modern high speed (370, 373, 390, 395 classes) trainsets from Hornby and similar brands in P4?? To have a main line in a layout that can keep a Eurostar running to a scale 330kph what would be the minimum radius? And turnout numbers? There´s need to have scale swingnose frogs, or longer numbers sufice? The results multiplied by 1,19 would be valid for S scale also or there other specific consideration? The layout will be this plan, that I´ll put in the background in templot and scale up until the minimum radius (the lower portion of photo near triangle?) of mainline be the desirable to this requirement. There´s two photos attached showing the plan. Any comments and opinions are very welcome. 1871_011836_180000000.png  1871_011902_400000000.jpg  |
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posted: 2 Mar 2012 09:36 from: Alan Turner
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It all depends what you mean by "scale 333kph". If you mean the naive calculation that is often banded about of 330/76.2 km in 1 hour then you could probably get away with sharp curves. If however you mean a true scale speed to correctly represent the dynamics, then your model will need to travel at an actual real speed of 330 x square root of 76.2 = (appx) 2880 kph. I think at that speed you need the same curves as the prototype (if you can get it to stay on the track - especialy when it exceeds the sound barrier!) Alan |
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posted: 2 Mar 2012 11:32 from: JFS
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Ewerthon Mota wrote:To have a main line in a layout that can keep a Eurostar running to a scale 330kph what would be the minimum radius? For me the answer is very simple - if you want scale trains running at scale speeds then you need scale track - so just model the real thing reduced in scale!! And one thing is for sure - you won't be able to build a "Scale" ultra high speed turnout in 00 - unles someone can prove they have already done it? Oh and by the way, not even the real thing runs through diverging junctions at 330kph! Best Wishes. Howard. |
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posted: 3 Mar 2012 20:48 from: Ewerthon Mota click the date to link to this post click member name to view archived images |
Alan the question in fact is the scale speed 330/76.2 or, most probably, 330/64 wich in the case is 5,16 km/h, put in that terms doesn´t seem any anormal figure. The dynamic thing is out of question. So there isn´t any formula to this? In the prototype is that something similar to 330kph=4000mradius, but it doesn´t scale lineary (5,16 doesn´t need 62,5m radius), as I´m in the stage to design the layout I think its time to worry about this, as I wish to run any possible equipment. I´ll use very broad turnouts, at least for model railway standarts, N°12 minimum for main line, and some even larger like a crossover of F20, but yes, even on N scale the generous space that I have isn´t enough to a high speed scale railroad. Is just want the sharpest curve in layout to operate at scale 330kph without having to slow the train. And in the plan that I attached doesn´t have a diverging path on mailine at the turnouts. | ||
| Last edited on 3 Mar 2012 22:38 by Ewerthon Mota |
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posted: 3 Mar 2012 22:05 from: Pete Brownlow click the date to link to this post click member name to view archived images |
My thoughts are that you need the speed that will look right - accurate scaling by one rule or another may not work. Bear in mind that you will be looking at it with an out of scale pair of eyes that are about a scale 20ft apart, so all aspects of perspective as the trains approaches and recedes will also be out of scale. There are lots of videos on Youtube of Eurostars and TGVs passing at full speed. I would suggest having one of these on your screen, then set up a test track and run your Eurostar until it seems to be passing at about that speed . That gives you a scale visual speed. As for the curves, there is no doubt that the model will go round curves far sharper than the real thing at that sort of speed without coming off - but it would just look very silly, in fact it would make it look like a train set. So once you've decided what speed it needs to run at to look right on the straight, you then need to run it round various curves (with transitions) until it stops looking realistic. I think you'll have to do some real experiments. Just trying to scale things will not produce something that is convincing. Sorry if that is not the P4 way.... Regards, Pete |
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posted: 3 Mar 2012 23:14 from: John Preston
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In 4 mm/ft, 60 miles pe hour is 88 ft / sec, or about 1 real ft/sec. Looks about right, and is expected from all but the slower goods trains. 330 miles/hour calculates out to just over 5 1/2 real ft /sec. It may be necessary to re motor and re gear any engine in order for it to approach this speed. Additionally, consider the length of track required for an engine to accelerate to this speed from a full stop. Hope this sheds some light on the subject. Cheers John |
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posted: 4 Mar 2012 09:26 from: Alan Turner
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As I said it depends on what you are trying to do. The question concerned the road holding ability of the model. Therfore that concerned the model dynamics and in order to examin that at 1:76.2 the required real speed of the model will need to be approx. real speed x sqrt(scale). In order to observe the model you need to take a cine film of the model and play it back at sqrt(scale) of the original frame rate, to give real time observation. If your question is "we want it to look right" then the naive answer is actual speed/scale but then you are saying nothing about the model dynamics or its road holding ability. The only thing you are modeling is the look of the model and you are not answering the original question. Alan |
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| Last edited on 13 Mar 2012 23:22 by Alan Turner |
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posted: 5 Mar 2012 22:43 from: Ewerthon Mota click the date to link to this post click member name to view archived images |
I think this time I understood the question and in fact only the look matters in case. Just look right. The model dynamics doesn´t appeal to me. I´ll will do the remotoring of this units as well as new gears. | ||
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