BIG - Integrated Ticket
Price: € 4,00
Validity: Until midnight of the day on which the tickets is validated; good for unlimited rides.
Where you can use: - Atac buses - Cotral buses (urban routes) - Cotral Trains: Roma–Lido, Roma–Viterbo (Rome - Sacrofano leg), Roma–Pantano - A and B subways (for one trip , including those requiring switching lines without having to pass through the turnstile) - FS trains (one trip, one direction)
In order to be valid: the BIG ticket must always be stamped at the beginning of the first trip. Validating machines are located: on the buses, trams, the Roma-Pantano and Roma-La Giustiniana trains, subway turnstile entrances, Roma-Lido trains and FS trains. The BIG ticket must be conserved until the carrier has arrived at its destination, and shown, upon request, to the ticket inspector. BIG tickets purchased at the B line subway stations are of a different size than standard tickets and can therefore be validated only at the B line subway stations.
BIT - Timed Ticket
Price: € 1,00
Validity: 75 minutes from the first validation Where you can use: - Atac buses - Cotral buses (urban routes) - Cotral Trains: Roma–Lido, Roma–Viterbo (Rome - Sacrofano leg), Roma–Pantano - A and B subways (for one trip , including those requiring switching lines without having to pass through the turnstile) - FS trains (one trip, one direction)
In order to be valid: the BIT ticket must always be stamped at the beginning of the bus ride or upon entering the subway platform (before the 75-minute expiration, the ticket must be re-stamped in oder to remain valid for the entire trip). Validating machines are located: on the buses, trams, the Roma-Pantano and Roma-La Giustiniana trains, subway turnstile entrances, Roma-Lido trains and FS trains. The BIT ticket must be conserved until the carrier has arrived at its destination, and shown, upon request, to the ticket inspector.
See also:
Roma - ATAC - http://www.atac.roma.it/biglietti/
Metropolitana di Roma - http://www.metroroma.it/Metroroma/
Subway maps (includes Rome trains) - http://subway.umka.org/map-rome.html
RomeBuddy.com - http://www.romebuddy.com/givesadvice/metropasses.html