the Port Reading secondary is near my home and over the past year I've noticed an unusual sound as trains pass. there's a humming/buzzing noise emanating from the wheels on the rail, the pitch of which is speed dependent. it's almost as if there is texture on the wheel face or rail.
I don't think it's related to brakes, as it also occurs as the train is increasing speed.
as I think more about it, I hear it most with the unit tank train. inbound so they're loaded.
any trainmen care to comment on this?
