Those are brass screws (Robertson type) that serve as fix points to solder the rail to. Through the tie and into the plywood.
Home made track gauge using NEM standards.
Closure/guard rail combo that leads to the frog.
The hole is in the stock rail in the points area; to hold the rail in a fixed position without soldering points.
Yes, it is all C215 NS rail from Llagas Creek. Tough stuff, hard to file. I machine whatever is easier to machine than file.