pewky Posted February 3, 2014 Share Posted February 3, 2014 Dear all, I am planning to build some track and I have chosen the C & L components. Unfortunately I need a diamond crossing. There are few available but I was wondering what do the different ratios mean i.e. 1:5 ; 1:6 etc..? Is that anything to do with the Pythagorean relationship to use to determine the angle? Thank you for your help Luc Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted February 3, 2014 RMweb Gold Share Posted February 3, 2014 Dear all, I am planning to build some track and I have chosen the C & L components. Unfortunately I need a diamond crossing. There are few available but I was wondering what do the different ratios mean i.e. 1:5 ; 1:6 etc..? Is that anything to do with the Pythagorean relationship to use to determine the angle? Thank you for your help Luc It isn't actually a ratio but what amounts to an angle. Crossings (as in common crossings, what some modellers call 'frogs') in pointwork have an angle and the '1 in' figure relates to the distance from the nose of the crossing to the place at which the diverging rails become1foot apart (on the real thing that is). Thus on a 1 in 8 crossing the rails leading out of the common crossing become 1 foot apart at a distance of 8 feet from the nose of the crossing - the 1 foot is measured across the running edges of the rails. Hope that makes sense - but forget the idea of a 'ratio' and think in terms of an angle. Link to post Share on other sites More sharing options...
pewky Posted February 3, 2014 Author Share Posted February 3, 2014 Pythagorean is not correct more to do with trigonometric calculation then? Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted February 3, 2014 RMweb Gold Share Posted February 3, 2014 Pythagorean is not correct more to do with trigonometric calculation then? Or a tape measure (on the full size thing - as we sometimes had to do after a derailment and the pointwork components had little evidence to indicate what the crossing angle might be) the civils have tables etc for all that sort of thing. Link to post Share on other sites More sharing options...
hayfield Posted February 3, 2014 Share Posted February 3, 2014 Luc Are you using a C&L plan? and If so what is the crossing angle? and the other questions scale and gauge Link to post Share on other sites More sharing options...
Debs. Posted February 3, 2014 Share Posted February 3, 2014 Hello Luc., Have you come upon the excellent track-design and layout-planning software named "Templot" Templot is wonderfully useful, works for many gauges and scales and is both free to download and to use and is well supported by fellow users within a friendly Templot Club forum. I think you would surely find it helpful in your design and construction of non-commercially available formations (such as your diamond crossing). Link to post Share on other sites More sharing options...
hayfield Posted February 3, 2014 Share Posted February 3, 2014 Luc I miss-read your posting, if the crossover is going to be close to the turnout the chances are that the crossing angle of the diamond will be the same at the turnout it comes from. The question is what plans are you using. As Debs has advised Templot is a super program for making track building templates (plans) and you can make and print off easily a matching turnout and diamond crossing Link to post Share on other sites More sharing options...
pewky Posted February 3, 2014 Author Share Posted February 3, 2014 Thank you Debs, This will certainky be usefull. But I do not have any personal computer and I believe templot is not yet available for androids platform. Luc Link to post Share on other sites More sharing options...
RMweb Gold martin_wynne Posted February 3, 2014 RMweb Gold Share Posted February 3, 2014 I was wondering what do the different ratios mean i.e. 1:5 ; 1:6 etc..? Hi Luc, There are 2* common ways of measuring crossing angles, called RAM and CLM. Here's some info copied from the Templot forum: RAM = Right Angle Measure = Templot default and some Continental European prototypes: RAM unit angles are traditionally used by modellers because they correspond with normal engineering practice and are easily set out with dividers -- all measurements are either along the rail or at right-angles to it. Templot uses RAM angles by default for this reason. _________________ CLM = Centre Line Measure = most US and UK prototypes: CLM measurements are made along an imaginary centre-line between the vee rails, and at right angles to that centre-line. Neither measurement is along the rail. It's easy to do on the ground with gauging tools which fit across the rails, but more difficult on a drawing board. CLM unit angles are used because the rules-of-thumb formulae which are used by the p.w. gang when setting out pointwork on the ground are simplified, and produce closer approximations to the true mathematical result. Nowadays with everything done on computers there is no real need for unit angles, we could work directly in degrees or radians. But tradition dies hard and the unit numbers are brain-friendly and easy to remember. Note that for increasing length (flatter angles) the difference between CLM and RAM diminishes.For modelling purposes the difference in angle is insignificant, but it makes a measurable difference to the lead length of a turnout. Try swapping from RAM to CLM in Templot to see the difference. *there are other ways, now obsolete. Martin. Link to post Share on other sites More sharing options...
RMweb Premium BR60103 Posted February 4, 2014 RMweb Premium Share Posted February 4, 2014 Should I point out one other horrible thing on the diagrams: The measure isn't from the end of the rails at the pointy bit, but where they would meet if they were filed to a really sharp point. Link to post Share on other sites More sharing options...
Michael Woolford Posted February 4, 2014 Share Posted February 4, 2014 Should I point out one other horrible thing on the diagrams: The measure isn't from the end of the rails at the pointy bit, but where they would meet if they were filed to a really sharp point.The 'pointy bit' on the diagram is the nose and the point at where the two rails would meet is called the intersection point. The reason for having a blunt nose is to due to the fact that if it were a long thin point all the way to the IP, wheels striking the nose would cause it to shatter with the possibility of damage to the wheels as well as the smashed up crossing nose. The nose is also ramped to decrease the impact of wheel striking. Michael Link to post Share on other sites More sharing options...
pewky Posted February 4, 2014 Author Share Posted February 4, 2014 Martin, That s great I should your post as a reference. Do you think C and L use the RAM or the CLM system? David I think this could be negligeable if you compare an 1:5 to an 1:6. Practically the only way to get the udeal fit to your track plan is probanly to build your vee yourself. I hope John yes this could be the case. Thank you all Luc Link to post Share on other sites More sharing options...
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