I'll put this out before I say anything else. I was born in 1984, so everything I know about the Central I've learned from 'fans, books, and a lot of walking.
Every thing I've ever read or heard indicates the Central's mainline from Easton to Lehighton was unchanged and fully active up until they left Pennsylvania. I know about the consolidations of track, but below Lehighton interlocking, the only changes to CNJ iron would have been at Lehighton, where the ramp was built, and at Bethlehem, where the bridge was modified and an interlocking built to let the Valley into Allentown yard. And I'm almost positive the bridge belonged to the Reading.
I'm not saying you're wrong mr. bang, just writing down everything I've heard up to this point.
Mike
telephone, telegraph, and tell a railroader
-S.E. Miller