I've been monitoring the Providence & Worcester Railroad frequency 160.650 off & on since I was a boy, I listen in particular for the transponder in Uxbridge, MA that reports the condition, number of axles & rate of speed when a train passes it. As if this freq isn't plagued with enough interference, lately there's a continuous data transmission on it. Best way I can describe it is it sounds like a big diesel motor, having been a radio hobbyist all my life I've heard this sound elsewhere so I know it's data of some kind. It's signal strength comes & goes, it's just strong enough to break my squelch every so often & be enough of a nuisance that I've been locking the channel out. So, I haven't been monitoring to see if P&W is still using the freq for FM voice or not, I only hope it's not them "upgrading" to some new data communications system and their not going to use voice any more. Does anyone know anything about this, or even what I'm talking about? Any info would be appreciated, Thanks!