Eurail
The granddaddy of them all, the Eurailpass is valid for consecutive days of travel in all 21 countries in the Eurail network (including: Austria, Belgium, Croatia, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, the Republic of Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Romania, Slovenia, Spain, Sweden, and Switzerland).
Thing is, if you won't be traveling-and using that pass-every day, you'll end up losing money on it. A 15-day first class Eurailpass works out to cost you $49.66 per travel day; a one month second-class Eurailpass costs $39.96 per travel day. If you don't spend those travel days on a train, or if you have any left over at the end, it's money wasted.
Flexipass
If you'll be in Europe for a couple of weeks or months and plan to spend a couple of days exploring each destination city, you might be better off choosing one of the Flexipass options. Flexipasses allow you a certain number of non-consecutive travel days to use at your discretion within a one to two month time period.
Country-specific and regional passes
If you'll be spending most of your travel time in a specific country—say, a semester in France or Germany—consider one of the country-specific or regional passes. France and Germany have a range of dedicated passes available, some of which allow consecutive-day travel and others which let you choose when you hit the road.
The Selectpass, a multi-country rail pass, allows you to choose three to five bordering (or connected by ferry, in certain cases) countries among the standard 18 Eurail countries. A trip to admire the works you've memorized for your art history classes will lead you to France, Italy, and Greece. The first two share a border; Italy and Greece are linked by ferry, and your Selectpass will give you a discount on certain ferry lines (you're still responsible for seasonal surcharges and couple euros' worth of port taxes, though).
Regional passes are perfect for trips that will keep you in one large area, especially if that area is not among the standard 18 Eurail countries. The European East Pass, for example, offers five non-consecutive travel days in Austria, Czech Republic, Hungary, Poland, and Slovakia - which is perfect if you want to spend a month exploring Poland and the Czech Republic. Some of these passes allow you the option to add extra travel days to your pass for an additional cost. Again, planning ahead can pay off well.
Britrail
Great Britain is not included in the Eurail network, but the BritRail Pass (see our separate section to learn more) covers the island and comes in several configurations. Most BritRail passes include airport transfers into London on the Heathrow, Gatwick, or Stansted Express trains. Some of the passes also offer discounts on the Eurostar trains to Paris. Airport transfers are also available separately-in case your flight lands in London but your travels begin elsewhere.
Next page: How railpasses work
