I've noticed in the north west of England, especially between Lancaster and Warrington, station staff seen to be using non analogue radio's. They use something that not only allows them to talk to each other, but connect to the PA system to make announcements.
I had:
Preston and Crewe, 453.550 / 94.8Hz,
Lancaster 453.550 / 82.5Hz
Warrington 453.550, never got the tone.
Carlisle is 453.550 / 118.8Hz, I didn't here it the last time passing through.
All the above are Virgin Trains used. Carlisle also has 446.1625 /103.5Hz, the user is Northern Rail.