Not normal anymore, although I think they still run on some lines.
I have met people who claimed to be able to tell which type of train was coming by sound alone, so they knew whether they needed to duck to avoid getting the brown mist straight in the face.
Well yes, I was told this by somebody who'd found a bag full of what was somehow determined to be human faeces while inspecting part of a tunnel, while waiting for a track possession to inspect the rest of the same tunnel.