"In fact, I got free wi-fi in Embarcadero station while the train was idling there. What wi-fi can make it that far? Two serious stories below Market Street. Hmmm."
BART has its own wi-fi for the company, but you would've had to known what to set it to. T-Mobile, Verizon and AT&T wireless cards work down there on the same signal as the cell phones. Powell St. Station has the best signal throughout the station.