All the faders were train tracks

I'm at a mixing desk but every fader is a little section of train track, and the signal is coming in as the sound of wheels over joints. I keep trying to push a train past the bus stop where my dog is sitting, and she just watches me, patient, like she knows I'll get it wrong before I get it right. The monitor speakers are humming in C-sharp, which doesn't mean anything, but it felt like a clue I hadn't earned yet.