The estimated cost to operate and maintain PTC is up to $130 million per year.  The implementation of PTC cost over $4.1 billion and, though mandated by Congress, the state and local governments shouldered the bulk of the installation costs.  The implementation cost of PTC and the annual costs of operating and maintaining PTC come on top of the existing $100 billion backlog needed to bring the national public transportation industry into a state of good repair. This is a major challenge for publicly funded transit systems in dire need of upgrades.