Why do my ears get pressure when I ride San Francisco BART?

Question

I don't think the elevation is changing; rather, we just go really fast and for some reason the pressure builds quickly and I have to swallow to release the pressure in my ears.

Answer 1

The giant ventilation fans create positive pressure in the wye. The vent pressure is higher at the inlet end of the 3.6 mile Transbay section.

Answer 2

It's b/c of the air pressure. But that actually depends on how far underground or how high the BART actually is. It's kinda like swimming in a pool. When you reach a certain pressure, your ears start to pop. This happens all the time. Hope that helped!