I recently moved to the top floor of a three story home that is near an infrequently used express track (primarily on weekends during construction on the local line/once or so an hour). A train passing under causes the house to rumble hard and generally wakes me. It's an old home, and it seems prone to vibration.
To minimize the train vibration in my bed (metal frame with four legs on risers, wooden slats, foam mattress), I put folded-in-two yoga mats beneath each pair of risers. Each riser also has two dense hockey pucks beneath the bed legs. I added a fully inflated air mattress between my bed and foam mattress. Beneath my bed are boxes of books for added weight; two ten-pound weights are on the bed-frame. No part of the bed is touching the wall.
It's helped with the train vibration, but it hasn't helped with what seems to be the entire upper floor shaking very rapidly and constantly. It tends to start in the evenings during the weekdays. This past weekend, it was on the entire time. My landlord (lives on the first floor; I'm on the third) said he's never heard of nor experienced something like that in the years he's been there.
My second floor neighbor doesn't seem to be experiencing anything (but he also mentioned that his family's encounters with the trains seems to be far milder than mine). He also mentioned that he doesn't have any vibrating machines in use (fan, AC, etc.)
We had some boiler repairs recently (I don't know what was done), but the vibration continues even when the radiators aren't fussing about. It's still active when our refrigerator dies down. I tried recording it with the VibSensor app and got rates of 9.7-10hz, but I'm not sure if that's the app just picking up itself. No music, broadcasted or performed.
The room's former occupant (who I don't think spent much time in the apartment during the winter) doesn't recall any such vibrations.
Is this something new? Is something broken? Could it be something 'normal' and otherwise present but now accentuated because it's colder outside? How do I stop it? I'm very sensitive to my environment, but my landlord is at least in his late fifties, so I'm concerned he might not pick up on the vibrations.