The full situation is this: I was thinking about retrofitting easements into a layout that I already designed without easements. Exactly as you guessed, on either side of the sample curve I mentioned, there are turnouts that I would prefer not to move if possible.
In 3rd Planit (I use version 8.01), I went to the “Custom spiral lengths” window and reduced the “Short spirals” setting to 13 from the default value of 20. I also set the connect tool to use this short spiral length. I then used the “Connect with easements” tool to join the two turnouts and created as wide a radius as possible.
According to the Properties popup window, this spiral section has:
Radius 21.746"
Length 4.934"
Azimuth 270 degrees
Offset 0.047"
The point of this exercise was to see if I could just add easements to the existing design. Compared to the parameters you are using, I am not sure if the minimal easement I have added(offset of just 0.047") will really improve running characteristics. Its clear that I would have to redesign my layout a fair bit to make proper use of easements.
Have you ever held a fishing pole up against the cieling? You will notice it natrully forms a transition curve becuase it gets thinner toward it’s tip.
I draw the straight sectins first. Then using heavy cardboard or whatever you want draw the curves radius and cut it out. Make the radius cutout at least 90 degrees, but if you have two straight sections intersecting at a sharper angle than you need to go to that angle with your cutout.
Place the cutout 1/2" away from the tangents ( straight sections). Draw your radius on the layout with a felt tip pen.
Place some nails or whatever to hold the tip of the fishing pole at the center of your radius (this doesn’t have to be perfect on center) and pull the but (bigger end) of the pole to line it up with your straight section.
You will see a nice transition formed by the pole. Use the felt tip pen to draw your transition. You may have a few rough spots if you run the pen around the poles guides. Just dont draw there.
If your using cork roadbed it’s easy to eyeball the cork to conform to the transition, or the flextrack for that matter.
My layout because of space limitations forces me to go with #5 turnouts 26" Rad. Because of the good transitions my six axle deisels go around at full speed smooth as silk. Transitions DO make a big difference.
Guy’s say " How did you make such dynamite transitions", I hold up the tip end of my fishing pole. The look on there face is priceless.
rxanand wrote: I was thinking about retrofitting easements into a layout that I already designed without easements. On either side of the sample curve I mentioned, there are turnouts that I would prefer not to move if possible… It’s clear that I would have to redesign my layout a fair bit to make proper use of easements.
Yes, rx - The extra length needed is actually the major impact of having easements. Everybody obsesses about the 1/2" +/- offfset, but it is the 8" to 12" half-easement length that has the biggest effect, because (as you noticed) it requires that much more length before you can have a turnout, and thus stretches out the whole track plan. - gerhard_k