Welcome to BYC! I live in the suburbs of Denver, and my chickens do just fine in the schizophrenic weather. Just don't get silkies or frizzles unless you plan on having a heater in your coop. I keep Naked Necks and they do great! As for the train, I live near a train and it doesn't phase them, neither does the lawnmower, leaf blower, wood chipper, or any of the loud tools my neighbor uses right next door on the other side of the fence from their coop. Have fun!!
