Good morning all:
Bruce -- Please forgive my lack of specificity; my ruling curve is O63. This was a regrettable compromise for the space I had available to me, and the broadest curve I could reasonably get away with. The outside staging track, which hugs the mainline curve in one of the pictures above, is O72, as are the wye turnouts in the yard, which also contains a few #7 turnouts. Hence, the aforementioned scale GG1s would only be able to test there. You're welcome to stop by any time! I'll post a track plan in my own thread sometime this week.
As far as prototypicality goes, it has usually been my practice to closely model the wire construction and immediate catenary support structure against a prototype, while employing my own designs for the extended support structure and poles. That allows me to be creative on the extended structure to support catenary-powered trains as needed, while staying faithful to the prototype where the 'shoe meets the wire'. My previous catenary layout got a little out of hand with support structure, so I endeavored to be as efficient as possible with poles and supports. You'll see in subsequent pictures where poles serve multiple purposes, which makes things look more tidy and elegant.
I actually have the old Pennsy mainline about 9.5 minutes north of my house, which is probably one of the reasons I got hooked on heavy electric modelling. Pennsy engineering is the standard and seldom bested even with today's 'technology'.
Randy -- I've not wired a tunnel before, but I concur with Bruce's plan. That seems like a juicy challenge to tackle; the harder the better. And all the more fun when a solution is realized!
I understand both of your views with regard to powering trains with the overhead. To me, an overhead catenary system isn't doing it's job or even worth it's own existence if it's not powering trains. I suppose it's the engineer in me, or a quirk or personality that I get such a charge out of difficult technical challenges and insist on a high level of purposeful operation. It is at the same time frustrating and great fun to get the wire in line, build durable pantographs using conductive grease while ensuring they are sprung properly, reverse-engineering available locomotives where needed to run smoothly off overhead, and generally performing all the wire maintenance or repairs needed, just like the real catenary maintenance crews do. It could scarcely get better than that for me. 
