Whats the distance of train station a to train station b
O O O O B-SL_SOURCE_IN_GET_LOCATION_SL_POINT_ON_MAP I-SL_SOURCE_IN_GET_LOCATION_SL_POINT_ON_MAP I-SL_SOURCE_IN_GET_LOCATION_SL_POINT_ON_MAP O B-SL_DESTINATION_IN_GET_LOCATION_SL_POINT_ON_MAP I-SL_DESTINATION_IN_GET_LOCATION_SL_POINT_ON_MAP I-SL_DESTINATION_IN_GET_LOCATION_SL_POINT_ON_MAP