Part 1 - Building a #7 Turnout (Placing and Spiking the Rails)

The NMRA website (https://www.nmra.org) contains a set of recommended practices for building turnouts. Specifically RP-12,  RP-12.x and TN-12 (There is also RP-13.5,6,7,8).  

For quick reference RP-12 and the appropriate RP-12.x document will be used. (For this build RP-12.5 Proto48)

After spiking the straight stock rail, the position of the frog point (red circle in the above photo) is measured from the turnout points and marked. 

The distances for three locations along the curved closure rail are listed in the RP-12.5 document. 

Each location is determined by measuring from the turnout points along the straight stock rail and then from the center of the straight stock rail's railhead over to where the center of the curved closure rail's railhead will be located. (See above circled in red)

Spiking of the rails can begin after the positions are marked and electrical feeder wires are soldered to the frog and rails.

(It is not necessary, but I usually spike the rail leading into the turnout's frog first.)

Once the frog is positioned and the track gauge verified along the frog's rails, the frog is secured with spikes.

After the frog is secured, the curved closure rail is spiked using the marked locations to guide the position of the rail.

The remaining two rails (the straight closure rail and the curved stock rail) are spiked into position based on the track gauge from the corresponding spiked rail.