Were you not aware there was a train next to the building before you moved in or that it was by a main street? I mean those things are kinda hard to miss. Not sure if it's an issue that can allow you out of your lease since it seems like a lack of due diligence on your end but I would ask building management anyways. If not suck up the fees and find another place. For your next place, google the area, visit the area in the am, eve, and night and insist on seeing the unit as a condition of your lease. My guess would be that even if you move to another apt in the building, it may only be marginally better than your current one. Or just suck it up, you'd be surprised how easily you become used to trains (used to live next to one) and other noise pollution.