"PL" is the Motorola "slang" name for CTCSS (continuous tone coded squelch signal [or system]). In the early days before trunking, all the "biggies" had their slang names for CTCSS:
Motorola - PL (Private Line)
General Electric - CG (Channel Guard)
RCA - QC (Quiet Channel)
I'm sure I'm missing some, and someone like Mike (ka3jjz) will give me a hand. Now, back to the question... for FD, try 155.760, CTCSS 141.3 (4A), and for PD, try 159.090, CTCSS 146.2 (4B). I generally have no problem picking them up from Bryan's Road, but they're so quiet (infrequent transmissions), it's hard to park on the channel to asses the signal strength.
Dewey