In the era of trainphones and the PRR, was every loco fitted with trainphones, i.e. the “handrail antenna” along the top of the loco?
You may have seen this already, but Jerry Britton’s Keystone Crossings website has probably the best collection of Pennsy material on the web. Here’s the write-up on Trainphone:
http://kc.pennsyrr.com/faqs/trainphone.php
Based on photographs in my collection, it appears that Trainphone was most often applied to mainline locos and cabins. Switchers were rarely so equipped, and neither were most 2-8-0s or 2-8-2s (although many still ventured out onto Pennsy’s busy 4-track main in local service). It looks as if class N6 cabins never got Trainphone either. The N5 variants were hit-or-miss. However, ALL road diesels up through the GP30 appear to have received Trainphone.
Trainphone was not actively used in the electrified zones, but I have seen Trainphone-equipped locos and cars under the catenary. When in doubt, refer to prototype photos for each locomotive or cabin.
Thanks! That was quite informative! 
John