I've decided to try a represent multiple eras on the layout. While I am a huge Pennsy fan, the real Pennsylvania Railroad was long gone before I was even born. When I first went to Horseshoe Curve, Conrail was running the show. Since 1999, the line has been owned and operated by Norfolk Southern.
I Already have a fleet of modern-era freight cars and some Conrail and NS units. All I need to do is take the Pennsy stuff of the layout and put the Conrail/NS equipment on. I can even throw Amtrak into the mix if I so choose. Fellow Pennsy modeller Dave Vollmer does exactly that on his layout.
Okay, there is one little flaw in this plan. My trackplan calls for four tracks; Conrail removed one track in 1981. Oh well, when faced with choosing between accurate for the Pennsy or accurate for Conrail/NS, I choose Pennsy.
I've already started repainting some of my Cherokee Foothills locomotives into Conrail blue. I will post some photos when they're all done.