In about six months, passengers on public transport in Athens will be able to use smart cards. The cards will be accepted on all forms of public transport and will be priced on a sliding scale for one day, one week, one month or six months. Passengers will validate the cards in special machines installed on all public transport. At present, the system is available only on the trams. The machine will automatically register whenever a passenger with a smart card boards public transport, and will reduce the value of the card by the appropriate amount, depending on whether it is the metro, a bus or the suburban railway.