It's worth mentioning that in addition to the rails, the passes are valid for travel on some shipping, ferry, and bus lines. They also offer discounts with other businesses of interest to the traveler, including some ferries the pass doesn't cover entirely, plus hotels, car rental agencies, and even mountain cable cars and bicycle rentals.

It's important to know that the Eurail pass doesn't include England, Scotland, and Wales. If you're traveling to one or more of these countries, you'll need a Britrail pass--they offer plans similar to the Eurail system's.

To maximize your savings, it's important to map your trip well so you don't buy the wrong pass for your trip. Group travelers can save money by purchasing passes together--but they must also use the passes together once they arrive. And certain passengers, such as youths, qualify for discounts.

You should also know that even though the passes theoretically offer free run of the train systems once you've paid the blanket fee, in certain circumstances you may have to pay additional fees.

Our final tips are to remember that you must purchase passes before arriving in Europe, and it's important to make reservations for individual train journeys, especially for sleeper cars and in high-traffic times.