At first I heard a sound, a roaring sound that I assumed was the train. It might have been the train. I heard it again, but it seemed a bit closer this time around. I looked out of my window and saw a flying vehicle, no telling whether it looked human-made or extraterrestrial but what I saw was a dark triangular silhouette with three non-blinking orbs on each corner of the triangle. It seemed to be levitating and slowly moving north without propulsion, though there was that accompanying high pitched roar, and a second low pitched roar that can be heard below the first, humming in dissonance. I had to process the event for a minute because "UFO" didn't really jump in to my mind until I finally ran out of explanations for what it was. So I walked out of my house, followed it, but it was moving too fast for me to catch up with, and I was walking up hill where the houses start to block my view of the object. I don't think the object has left, because every now and then I hear the roaring-humming noises come in and out in different lengths of time, as if patrolling.