Disclosed is a system and method for tracking mass transit vehicles, including monitoring a Base Station IDentification (BS ID) of a base station registered with a communication device; identifying a change in said BS ID; determining a current location of said communication device; determining a previous location of said communication device; calculating a distance d between said current location and said previous location; determining a subway exit closest to said current location; determining a distance dc between said current location and said subway exit; when said distance dc is less than an exit threshold, determining a subway entrance closest to said previous location; determining a distance dp between said previous location and said subway entrance; when said distance dp is less than an entrance threshold, determining a direction from said previous location to said current location; and identifying at least one subway train based on said entrance location, said exit location and said direction.