To get a little more specific, here are some local details for many of the above posted frequencies:
CSX
160.230 - Philly Subdivision Road Channel
161.100 - Philly Sub "AV" Dispatcher Desk
160.530 - Philly Sub Yard Ops
160.890 - Philly Sub Maintenence of Way (MOW) PBX
160.785 - Philly Sub MOW mobile-mobile
160.875 - Philly Sub police mobile-mobile
Norfolk Southern
160.800 - Road/Yard Ch. 1 (former Conrail)
161.070 - Road/Yard Ch. 2 (former Conrail)
160.860 - Road/Yard Ch. 3 (former Conrail)
160.980 - Road/Yard Ch. 4 (former Conrail)
161.130 - MOW (former Conrail), PBX Base
160.710 - MOW (former Conrail), PBX mobiles
161.430 - MOW mobile-mobile
160.560 - Police Dispatch (NS-1000)
160.690 - Police car-car
Amtrak
160.920 - Northeast Corridor Road Channel
161.295 - Police Dispatch Repeaters
160.365 - Police Repeater inputs
161.205 - Police car-car
173.375 - Police crossband (repeats Wilmington PD in the train station area)
161.445 - Bear, DE Shops
160.650 - Station Services
160.515 - MOW
161.505 - Car Dept. (@ stations)
Since the railroads share the same 97 frequencies (more with narrowbanding) nationwide, the channel designations change as you move around the railroad. Everything listed aboove is local to the Philly metro area (including northern DE).