So I live in Indiana. I listen to the NFS Huntington district. Freq: 160.380. Sometimes I hear tones that sound almost like dialing on a phone. Or just a single long tone. Anybody know what these mean? I can try to record some of them.
They're DTMF tones train crews and/or maintainers use to contact the dispatcher. Since the dispatchers typically don't monitor each and every base station on their territory, in very laymen's terms the tones activate on the dispatcher's console so they know to answer the radio on that base. The dispatcher doesn't hear the tones.