radio channels- AM or FM - Trains Magazine

It would be very easy to turn a 100 channel scanner into a "railroad" scanner by simply programming the AAR Channel numbers in to the appropriate scanner channels. I don't recall if there is a "AAR Channel 1", but if there isn't, a body could simply put in an EOT frequency as most scanners like to have a channel 1

VHF High-Band generally isn't as susceptible to interference as some other bands, so you shouldn't have too much trouble leaving all the channels open. When one lights up, you can tell the AAR Channel by looking at the scanner channel.

There are several websites that have state-by-state scanner laws, as well as sites listing all the AAR Frequencies. A search should bring them up. If you don't have a 100 channel scanner, the tactic of searching for local frequencies lists is the method I use most often.