From what I understand, putting a local commuter train system is always much more expensive. As to the concern that the homeless will use it for warmth, this is always a concern, but that has not been a problem in the DC system. The appropriate procedures need to be implemented to verify that no one remains in the system after it closes [[if it closes). As for the people urinating, that's disgusting and needs to be dealt with in the design to ensure that the possibility for this does not exist.

The advantages of the above ground system are that people get the chance to see businesses and attractions that they travel past and may decide to visit later. It also helps to connect the commuters to the community.