# main class
class TransportationSystems():
    def __init__(self):
        self.highways = Highways()
        self.railways = Railways()
        self.lightrail = LightRail()
        self.airport = AirportTransportation()

    def busSystem(self):
        pass

    def portAndHarbor(self):
        pass

    def ferrySystem(self):
        pass


# helper classes
class Highways():
    def __init__(self):
        pass

    def roadways(self):
        pass

    def bridges(self):
        pass

    def tunnels(self):
        pass

class Railways():
    def __init__(self):
        pass

    def tracksAndRoadbeds(self):
        pass

    def bridges(self):
        pass

    def tunnels(self):
        pass

    def systemFacilities(self):
        pass

class LightRail():
    def __init__(self):
        pass

    def tracksAndRoadbeds(self):
        pass

    def bridges(self):
        pass

    def tunnels(self):
        pass

    def facilities(self):
        pass

class AirportTransportation():
    def __init__(self):
        pass

    def facilities(self):
        pass

    def runways(self):
        pass

