Exactly, @MarkE. The rails are soldered onto the crossties.
The other CNCable part I’m doing is the frog (crossing nose to the Brits) where the two “center” rails cross. Here is my former experiment, this past weekend I machined new frogs to go with my new turnout bases.
The rest of the rails (in my case, at least) are .040" tall and made of nickel silver, thus my choice of 1mm nickel silver sheet for the machined frogs. There are actually many other details to attend to. Here’s a YouTube video from a gentleman who goes about it a little differently and 3D prints alignment jigs. I will be CNC’ing my own alignment jigs to sit on top of the base. The little holes in the midst of my bases are for eventual alignment of the rail jigs.