I make my turnouts on the bench using templates. I mount the rail on PCB board ties. This is more comfortable that crawling around on the layout. Here we are going to "gang" three turnouts. This gives smoother trackwork.
The three HO Atlas turnouts are going to be replaced with handlaid track. When you design a layout make sure you leave clearance for switchstands like at "S".
A template was made by rubbing a crayon over the track.
Mark the tie locations and glue down the PCB ties.
The turnout is built from the first outside straight stock rail inward.
The stock rail at 1 is located by it's function as a point rail. The point rail at 2 is fitted from that stock rail. The turnout spirals out using the rail relationships as the arrows indicate
Our turnout article shows my method for mounting the ganged turnouts
(Click pictures to enlarge)