The pdf below is a chapter from the eBook "Italy from the Inside" by Francesca Tosolini.
It's written in English and this section of the book talks about public transportation -
specifically, how to use the trains in Italy


I have nothing to do with this eBook - but highly recommend the videos, podcasts, and blog posts on the Tosolini website:

There are great Italian language, culture, and travel resources (free) on the site. They also sell the eBook and other informational products.