The trainphone system and antennas was installed on most PRR diesels used in Road service. There were probably a few exceptions. Switchers did not get the system, but there were some Alco switchers I have seen photos of that have Trainphone antennas. They were probably used for transfer runs or something similar. I think some of the early road switchers may have come without it. ON the other hand, I think basically all Cowl units, Fs, Es, PAs, FAs, etc, got them.
I have been told that the system did not work in Electrified territory, but I don't know if the source was good.
And surprisingly, since the use of the system was in the transition era, there were some steam locos that had it installed. The antennas were installed on the tender deck.
The Withers books on Pennsy diesels tell you by unit, whether or not they had train phones or other options.
