Welcome to Signal Problems, a weekly newsletter helping you figure out what is going on with the subway. I’m Aaron Gordon, a freelance writer covering many subjects, one of which is transit for the Village Voice. On Sunday, I was walking by the Prospect Park B/Q/S stop. As you go down Lincoln Road, you can see the tracks to your left from the overpass. The tracks are slightly below ground level, weaved between rows of low apartment buildings. As I passed, a man had his son on his shoulders so the kid could see the approaching Q train. The train rounded the corner slowly but gracefully, as trains do from a distance, and the kid watched it.