It is CSX from Buffalo to Amsterdam then Amtrak to Poughkeepsie then Metro North until the Amtrak line to Penn Station.
CSX Road frequency is 160.800 Buffalo to Amsterdam. Most activity will be on the Road frequency unless they need to talk to the Dispatcher.
CSX Dispatchers are 160.950 Buffalo to W of Rochester, 161.400 W of Rochester to W of Syracuse, 160.560 in the Syracuse area and the 160.890 to Amsterdam.
Amtrak is 160.725
Metro North is 160.950 from Poughkeepsie to Spuyten Duyvil where the Amtrak line to Penn Station diverges and I am not sure of that frequency.
Everything is CSQ. While some railroads may encode PL, operation is generally CSQ for interopability