Rome has a terrific underground railway system that will get you near most tourist destinations. The Roman Metro has three lines - A, B and C, plus a new branch of the B line, called B1, which goes from the "Bologna" stop to "Conca d'Oro". The combination of A and B lines is X-shaped; the two lines cross at the city's central railway station, which is called Roma Termini. Line C is not yet connected to the rest of the network and has hardly any interest for usual sightseeing. 

In front of Termini station, there's also an important bus terminus. Don't be confused by all those different Bus Route numbers at stops! Just look at the direction the bus is heading, the arrow on the sign will indicate that, than scan the stops listed. If you are waiting for a specific numbered bus, but another route has a stop you reconize as close to your destination, jump on! One of the great things about being daring, and possibly getting lost, is that you cannot get That Lost, and second, you never know what you will find just wandering around. Explore!!!!

Rome has also an extensive network of trams and buses that will come in handy: it's a big city so trying to see everything by foot is simply not feasible. The whole metro, tram, bus, and part of the train network (comprising the Roma-Lido, Roma-Giardinetti and part of the Roma-Viterbo railways) is managed by ATAC, whose site comes with a handy route planner.

Rome's mini electric-bus routes are particularly helpful for visitors going to many of the popular tourist sights. Note that there are differences in routes for weekends and evenings.  Map of the mini electric-bus routes here.

An individual ticket for bus, metro, tram and trains inside the municipality of Rome is 1.50 € and is valid for 100 minutes. If you will be in Rome for an extended period of time, one can buy a seven day Metro and bus pass (called CIS) for 24 €. For shorter stays, one can get a day pass for 6 EURO, or a three-days pass for 16.50 €. However, especially when one stays in a fairly central area and if one likes to walk, buying 2-3 individual tickets a day may be the best bargain. Children less than 10 years old can travel on any bus, tram or metro for free if they are accompanied by an adult person with a valid ticket. Tickets and Passes fares are here.

The 'Roma Pass' is another option; it costs € 36.00 and gives you 3 days of free bus and Metro travel plus free and discounted museum/monument admissions. Alternatively, there is also a 'Roma Pass 48 hours' for € 28.00. A real bargain.  http://www.romapass.it/

You can obviously catch other trains from the Termini station: for example, you can transfer to the Frecciarossa train in order to travel to Florence for the day. The Metro maps are easy to navigate: beware at rush hours that the trains can get very crowded and you'll most likely be pushed into and out of the trains. This is also the time where pick pockets make a killing - so keep your wits about you!

 

Visit this page for 2014 info about mass transit system in Rome: http://davlynmitaly.blogspot.hu/2013/...