Italian trains have a bad reputation in regards to reliability. To some extent this is true, delays and cancelled trains are quite common. But they are not as bad as their reputation. Most trains are, if not punctual, pretty much on time.
Not only are train tickets cheap but Italy is also a beautiful country. In the northern part of the country, you have a number of railways going across the Alps. The most famous railways are the ones going into Switzerland. The Bernina Express is one of the most beautiful railway lines ever built. It runs from Tirano to Chur in Switzerland.
Another nice railway runs between Luzern and Lugano, although it does use the Gotthard railway tunnel. The Centovalli railway runs between Locarno and Domodossola. In summer, you can combine the Centovalli railway with a cruise on Lake Maggiore.
Traveling by train between the big cities in Italy is generally easy, although once in a while delays happen. At smaller stations it can be difficult to find someone who speaks English so basic Italian knowledge of Italian is very useful if you plan to travel around a lot in Italy. Especially if you are going outside the normal tourist destinations. At the larger stations, you can in most cases buy tickets from ticket machine that support English.
All the main cities have the railway stations in central locations. But in some of the cities the railway station are not in the best of neighborhoods so you may prefer not to sleep close to railway stations.
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