RMweb Gold Vistisen Posted July 20, 2016 RMweb Gold Share Posted July 20, 2016 *** Hi Vistiaen Its actually quite a fair question - and important to most of us... Its impossible at this stage to be 100% accurate to the decimal point... but the "Accurate Trackwork Modellers Answer" is - Its up to you to choose! IE: Measuring our prototypes and assessing the possible "totally safe / no risk" cut limits for the divergent track, the centres "as built" will be 50mm (Also needed anyway for tighter radii spacings). However its realistically possible and very easy to adjust the divergent track length to achieve slightly tighter than a fully prototypical minimum 6 foot way. I hope that answers your question well enough Regards Richard That was just what I need to know, thank you and circa 50mm is quite precise enough for me! Link to comment Share on other sites More sharing options...
Stephen Freeman Posted July 21, 2016 Share Posted July 21, 2016 Hi, The correct track centre measurement for 4mm scale is 44.67mm, however this should be increased for sidings etc and especially for curves, 50mm approx sounds reasonably safe for curves but of course if you intend running something like 70ft dreadnoughts or have sharp curves you might need to check it out. You can of course do this in Templot. Link to comment Share on other sites More sharing options...
Richard Johnson Posted July 21, 2016 Share Posted July 21, 2016 *** I am going to be a bit slow responding for the next 10 days or so. I am travelling to China and then in your direction :-) so - apologies in advance regards Richard Link to comment Share on other sites More sharing options...
RMweb Gold Vistisen Posted July 21, 2016 RMweb Gold Share Posted July 21, 2016 *** I am going to be a bit slow responding for the next 10 days or so. I am travelling to China and then in your direction :-) so - apologies in advance regards Richard Have a good trip and if it is not a holiday, a productive one Link to comment Share on other sites More sharing options...
RMweb Premium Clive Mortimore Posted July 21, 2016 RMweb Premium Share Posted July 21, 2016 Hi, The correct track centre measurement for 4mm scale is 44.67mm, however this should be increased for sidings etc and especially for curves, 50mm approx sounds reasonably safe for curves but of course if you intend running something like 70ft dreadnoughts or have sharp curves you might need to check it out. You can of course do this in Templot. Hi Stephen The minimum is 44.67mm. Link to comment Share on other sites More sharing options...
RMweb Gold Colin_McLeod Posted July 21, 2016 RMweb Gold Share Posted July 21, 2016 And the cat will not be able to breathe... Which won't be a problem if it's not there. 1 Link to comment Share on other sites More sharing options...
Stephen Freeman Posted July 21, 2016 Share Posted July 21, 2016 Of course if you're running GWR centenary stock, ex-broad gauge routes or some parts of the GCR it clearly needs to be more. As regards the dropper issue, things are pending until I get some more of the etched fishplates (C&L don't seem to do them any more and the Brassmasters aren't suitable for this application), so I'll just have to wait for the EMGS order to arrive. Members should note that they are now back in stock. Link to comment Share on other sites More sharing options...
AndyID Posted July 21, 2016 Share Posted July 21, 2016 Hi Stephen The minimum is 44.67mm. Of course you could argue that, if it's based on the method the prototype uses, it should be six feet plus half the gauge plus the rail width times two. To scale that would be: 24 + (8.25 + 0.8) x 2 = 42.1mm Link to comment Share on other sites More sharing options...
RMweb Gold martin_wynne Posted July 21, 2016 RMweb Gold Share Posted July 21, 2016 (edited) Of course you could argue that, if it's based on the method the prototype uses, it should be six feet plus half the gauge plus the rail width times two. To scale that would be: 24 + (8.25 + 0.8) x 2 = 42.1mm That won't work unless you use narrower trains than the prototype. The track gauge doesn't come into it. A better rule would be -- width of train plus 2ft. (9ft-3in + 2ft = 11ft-3in = 45mm) Martin. Edited July 21, 2016 by martin_wynne 2 Link to comment Share on other sites More sharing options...
AndyID Posted July 21, 2016 Share Posted July 21, 2016 That won't work unless you use narrower trains than the prototype. The track gauge doesn't come into it. A better rule would be -- width of train plus 2ft. (9ft-3in + 2ft = 11ft-3in = 45mm) Martin. I confess. It was a "wind up" aimed at those who insist 16.5 mm represents 4 foot 8.5 inches 1 Link to comment Share on other sites More sharing options...
RMweb Gold martin_wynne Posted July 21, 2016 RMweb Gold Share Posted July 21, 2016 (edited) It was a "wind up" aimed at those who insist 16.5 mm represents 4 foot 8.5 inches I know. Unfortunately I have seen that argument put forward seriously. Always remember this is RMweb. p.s. you got the rail width wrong. It should be 0.92mm. (2.3/4") Martin. Edited July 21, 2016 by martin_wynne 1 Link to comment Share on other sites More sharing options...
gismorail Posted July 21, 2016 Share Posted July 21, 2016 Best of luck in China Richard......... though your only as far as your lap top if you trying to get away from RM web Link to comment Share on other sites More sharing options...
AndyID Posted July 21, 2016 Share Posted July 21, 2016 p.s. you got the rail width wrong. It should be 0.92mm. (2.3/4") Quite so, but I was using SMP rail which is a bit too skinny Link to comment Share on other sites More sharing options...
RMweb Gold Vistisen Posted July 21, 2016 RMweb Gold Share Posted July 21, 2016 Quite so, but I was using SMP rail which is a bit too skinny At the risk of REALLY getting things going... If the rails are tilted inwards as they will be in the new DCC track, just where do you measure the track centre from? is the center at the top of rail surface, the bottom close to the sleepers, or in the center of the height? . And that is just your starter for 10. I have a follow up question for when the arguments die down a bit. Link to comment Share on other sites More sharing options...
RMweb Gold Colin_McLeod Posted July 21, 2016 RMweb Gold Share Posted July 21, 2016 I can't tell the difference when I measure the track with my school ruler. Its more than 16mm and less than 17mm so it must be 16.5mm. Correct?? Link to comment Share on other sites More sharing options...
RMweb Gold martin_wynne Posted July 21, 2016 RMweb Gold Share Posted July 21, 2016 At the risk of REALLY getting things going... If the rails are tilted inwards as they will be in the new DCC track, just where do you measure the track centre from? is the center at the top of rail surface, the bottom close to the sleepers, or in the center of the height? At the risk of taking track seriously in this topic, rail gauge is measured 9/16th of an inch below the rail top (14mm). That's because there is a 1/2 inch top corner radius on the rail head (13mm). That scales to 0.19mm below the rail top in 4mm scale. Martin. Link to comment Share on other sites More sharing options...
peterfgf Posted July 22, 2016 Share Posted July 22, 2016 Like the previous poster, at the risk of getting serious, the gauge should be measured with an internal micrometer which has a calibration traceable to national standards at the National Physical Laboratory. Vernier calipers are, at best, good comparators but are second best to calibrated micrometers - even the good ones from Mitutoyo and Radio Spares. The cheap ones available at some stalls in model railway shows are poor and may as well be used as G-clamps. Forget rulers for this sort of measurement. peterfg Link to comment Share on other sites More sharing options...
AndyID Posted July 22, 2016 Share Posted July 22, 2016 Like the previous poster, at the risk of getting serious, the gauge should be measured with an internal micrometer which has a calibration traceable to national standards at the National Physical Laboratory. Vernier calipers are, at best, good comparators but are second best to calibrated micrometers - even the good ones from Mitutoyo and Radio Spares. The cheap ones available at some stalls in model railway shows are poor and may as well be used as G-clamps. Forget rulers for this sort of measurement. peterfg Quite right, and layouts should only be built on a surface table, preferably granite Link to comment Share on other sites More sharing options...
RMweb Gold martin_wynne Posted July 22, 2016 RMweb Gold Share Posted July 22, 2016 Quite right, and layouts should only be built on a surface table, preferably granite Maintained at 68 degrees F. Link to comment Share on other sites More sharing options...
RMweb Gold martin_wynne Posted July 22, 2016 RMweb Gold Share Posted July 22, 2016 Glorious Twelfth comes 3 weeks early on RMweb. Link to comment Share on other sites More sharing options...
AndyID Posted July 22, 2016 Share Posted July 22, 2016 Maintained at 68 degrees F. You mean you've dumped SI already? Link to comment Share on other sites More sharing options...
RMweb Gold martin_wynne Posted July 22, 2016 RMweb Gold Share Posted July 22, 2016 You mean you've dumped SI already? This topic is about bullhead track. BS-95R rail is 5.23/32nds of an inch in height. How SI is that? Link to comment Share on other sites More sharing options...
Bernard Lamb Posted July 22, 2016 Share Posted July 22, 2016 Maintained at 68 degrees F. When quoting NTP for setting up an environment for accurate measurements, in the UK at least, it should be 70 degrees F. Bernard Link to comment Share on other sites More sharing options...
RMweb Gold martin_wynne Posted July 22, 2016 RMweb Gold Share Posted July 22, 2016 When quoting NTP for setting up an environment for accurate measurements, in the UK at least, it should be 70 degrees F. Is this the final proof of global warming? Link to comment Share on other sites More sharing options...
BG John Posted July 22, 2016 Share Posted July 22, 2016 This is model railway track that's being discussed, and according to my 1963ish Model Railways Handbook 7th Edition, the BRMSB standard for OO track centres is 50mm, measured from the centre of the sleepers. I hope that finally resolves this discussion . Link to comment Share on other sites More sharing options...
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