Laying out track and switches

My system is to first to drew the 1/2" scale layout until I liked it - biped a bit ago..   Then I spread tracing paper over the top styrofoam sheet.  On the paper I drew out the center lines of the track and switches.  I made a 30" curve on a large piece of cardboard for curves. I used a colored marker to draw the lines using a long measure stick and the curve.  This allowed me to make mistakes on the styrofoam - like the wiggle lines show - whoops.

Once this is done (all most) I will run down the lines on the paper with my  tool  that I use to add nail points on a structure - tool one of the extra photos.  Once done, I will take up the tracing paper and mark that the lines of holes with the pen on the foam.  Nest step is the lay track.

BTW the other extra shows another tool I use - a scan of a Sn3 switch printed at exactly the right length and size.  It makes drawing the track that is attaching to the switch.

Currently before all of this I am making sure of the size of the existing structures from the old ;layout, will actually fit correctly.  Easier to to be sure than removing the track - yuck.