While these are applicable ideas, I don't think I would use them. (Of course, you are free to if you want.) Magic is a chaotic, unstable force, and I seriously doubt that there would be widespread magical machinery. I should think that they'd overload, or simply cease to function, especially near the ley lines. However, I could see maybe some of the magically attuned races might be able to handle it, and you can never have too many ruins and remnants of a past civilization. Some of them might even still function haphazardly.