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Planning concentric curves with easements
The curve easement calculator is not much good if you can’t work with it, but only are allowed to read it.
What happened to the old (Westcott?) article on making templates? I thought it used to be available but can’t find it.
Cal
Unable to open concentric curve easement calculator and I have a PC. Is there an article published about this? Would sure be useful.
To Joe Zebrowski - it may open in Excel as “read only” but it should still allow you to input data and click the “compute” button to operate it. You should also be able to save a copy to your computer and, after that, change it anyway you wish.
Hope this helps.
Van S. Fehr
Again, I could not down load any of the downloads?
I could not run the micro on windows XP. My microsoft excel warned… to run the micro, request the macros to be signed by the author using a certificate issued by a Certificate Authority
Can you do this ? Thanks.
Difficulty opening:
I 've found that some downloadable MS files throw these errors if you try to open them from the link. Here’s solution that works 99 44/100% of the time. Save a copy rather than Open. Once it’s on your computer, it will open on a click of the icon.
I am having trouble using the calculator I change the inputs, push the calcuate button and nothing happens. I am using Excel 2007 will this effect the program.
I’m not sure if this is a windows 7 problem or not, but I went into “Tools” and set macro security to medium instead of high and now the program works.
The failure of “COMPUTE” is an Excel 2007 (and higher) issue, protecting against macros imbedded in the program. You can either lower the security as Rick did or elect to enable macros for this specific application. A P.I.T.A., but the price of security.
Not sure how this works but can’t get to work on excel 2010
either??
An excellent and timely article and Excel tool. I’m trying to fit four tracks around a corner and this provided a lot of help. One question - due to full passenger car lengths and 30 inch minimum radius, I end up with 32 inch long easements. How do I draw these on the layout? (My bending stick for easements is a yardstick!)
ALEX REED:
Try ripping a piece of the thinnest tempered hardboard you can find (1/8" best or 3/16" OK) into about a 1" wide strip, cut to about 8-12 inches longer than your longest easement. Make it match the tangent at the TS end, follow the curve radius at the SC end and pass through 1/2 the offset at mid length. You can use small nails or brads at the TS and SC ends to hold it in place, but don’t force it precisely to the mid point. Then draw your easment along the smooth side.
I had trouble with spreadsheet, but after saving to my pc, it worked fine. Windows XP.
Question: Can an easement be drawn in a CAD program? If so, how? By mathematical formula? This would be awesome if doable. I could print my drawing to scale (in sections if necessary) and use as a template for laying my track.
J D VOSS:
There are several CAD programs specifically designed for model railroad planning (see ads in Model Railroader) and these have built-in “easement” tools. In a general purpose CAD program, like the one I used to draw the illustrations in my article, look for a “spline” tool. It will do an excellent job of drawing easements.
Van - Thanks for your help. Trying to draw easements in my CAD program using spline tool. I specify start point, midpoint, and endpoint of easement, and then 2 tangent points, (end points of easement) but I seem to have a kink where easement meets circular curve? Am I missing something?
JD Voss: Your problem maybe in forcing the spline to match the curvature at SC (and perhaps TS). In CAD program, I use the “snap to” feature to force the spline to match the tangent at point TS, plus three more points on the tangent side of TS. I do the same at SC, plus three more points on the curve side of SC. This avoids the kink you may be seeing and may solve your problem. This, by the way, replicates the “Bent Stick” method used during actual construction. I hope this helps!
Van, awesome, I got it. Thanks very, very much for your help. Your article was very timely for what I was planning. It saved me from making the curves too close, and you showed me how space my curves, as well as to draw easements using a CAD program. I’m using my engineering now more on my model railroad, than in my job. Who’ed ever have believed that! I for one will be looking forward to any more articles you may publish.
Good tools to have handy when planning your pike.