I forgot to take pictures of how to build the wire subassemblies. I can do that later if there's interest; i'm going to need plenty more of them.
First, clip your wire subassembly to the inner rail, to make sure you're happy with where it's going to go.
Once you're satisfied with it's placement, bend all the vertical drops to the proper angle, so the top messenger wire has the right arc to it around the curve. Then retouch all the top solder joints to adjust the position and angles, so the entire wire subassembly maintains the exact curve shape when you unclip it from the rail.
Then use some wood blocks to support it across it's length at the right height, and solder the ends into the cross spans.
Add in the compound cross drops and other complex work as needed over switches.
Use some unpowered cars with properly sprung and working pans to test your work as you go.
Don't forget to put in the insulators.
The PRR had pull-offs in all kinds of weird places, so don't be afraid to use them to keep things lined up.
Make sure to keep the wire tight, and things should fall into place.
While i'm in the picture-posting mood:
Always keep plenty of power around, just in case.
Mmmm, steamy goodness.