Not train tracks, but I grew up close to SFO (major airport). Most days there was a decent amount of jet noise, never bothered me but after I moved I realized how quiet the middle of the night can be.
I lived in the flight path to Orange County Airport...the planes flew so low over my apartment, it was rad. Once a plane misjudged the landing and took out about 1/3rd of the row of car dealerships right near my apartment. The planes didn't bug me either, I never noticed them when I was looking at the place and I was surprised when I saw one. Like you, it wasn't until we moved that I realized how quiet it was at night. SNA has a curfew though, planes can't land or takeoff between 10 pm and 7 am, at least that was the case when I lived there.