Being a former train dispatcher, a current emergency services dispatcher, and all-around radio buff let me see if I can help here. I would put these 4 frequencies in-they were the 4 primary road frequencies for Conrail prior to the NS/CSX takeover.
This was listed as Conrail Road Ch. 1. It was the primary road channel for all trains on the Conrail Southern Tier Line between Suffern, NY and Port Jervis, NY. It is now controlled by the NS Southern Tier Dispatcher from Port Jervis, NY west to Binghamton, NY. Between Port Jervis, NY and Suffern, NY it is controlled by the NJT Mainline dispatcher. Being a former NJT train dispatcher on the Mainline I can tell you all trains west of Suffern, NY will switch to it. East of Suffern, NY all trains will switch to 161.400-the NJT Mainline dispatcher.
This was listed as Conrail Road Ch. 2. It is was the primary road channel of the Conrail Lehigh Line between Oak Island, NJ and Allentown, PA. It is now controlled by the NS Lehigh Line Dispatcher and is still the main NS route into and out of the NY/NJ metro area.
This was listed as Conrail Road Ch. 3. It was used by trains running on the various running tracks and secondaries in the central NJ area as well being used as by the many yards in the area as well. It is now controlled by the Conrail Shared Assets North Jersey Dispatcher.
This was listed as Conrail Road Ch. 4. It was used by trains running on the Conrail River Line as well as by trains in Southern NJ. It is now controlled by the CSX NJ Dispatcher on the River Line and by the CSX NI Dispatcher (the old Conrail Trenton Line).
I would also make sure you have these frequencies:
The NYS&W. They run from Little Ferry, NY to Binghamton, NY via their own mainline to Hudson Jct where they then switch onto the NJT/MN line into Port Jervis and on to Binghamton, NY.
The NJT Hoboken Division. The Hoboken Division is all trains on the Morris & Essex Lines, the Mainline, the Bergen County, the Pascack Valley, and the Southern Tier.
The NJT Newark Division. The Newark Division is the Princeton Line, the North Jersey Coast Line, the Raritan Valley Line, and the Atlantic City Line.
As for you not being able to hear much are you using a handheld, base, or mobile scanner? Antenna quality and location will greatly affect your ability to receive radio signals. Nothing beats a good antenna. You can have the best receiving radio in the world, in the best location possible, and if you have a cheap antenna you aren't going to hear as much as if you have a quality antenna on that radio. Of course the opposite is also true. A good antenna can make a mediocre radio perform better. Regardless of what type of radio you're using go to a good ham/scanner/cb radio store....they'll have antennas for all types of scanners as well. $25-$50 will get you a good-quality antenna. www.universal-radio.com
also has some great antennas for scanners.
These frequencies should keep your radio busy!