This study evaluated the accessibility of public transportation systems and the impact on the improvement of rail transit in selected Southeast Asian cities. Results clearly showed that the present public transportation network development varies greatly among the cities studied. The urban railway development significantly improved accessibility as a whole, but there are underserved areas indicating poor accessibility. Hence, it is essential to consider these results when setting up urban rail transit routes in the future. This research is carried out with the cooperation of  Kasetsart University, Thailand, De la Salle University, Philipines and, Vietnamese German University, Vietnam.