Purchase a reservation at most major international train stations in Europe, as well as many manned stations (but not all). Typically 2 to 5 Euros to guarantee a seat on a daytime train. You don’t have to have a reservation, but you risk standing if that train is sold out.

However… I’m not sure I’d want a pass for your itinerary. Passes don’t cover Eurostar (London to mainland Europe) and a quick look at advance purchase, midweek prices one-way to Amsterdam are only £51 adult, or £45 for students or under 26 years old. That would only leave Ams-Ber, Ber-Prg for train segments (right? … or were you planning to take train from Prague to Greece?). Otherwise, I’m assuming PRG-SKG flight, SKG-LON flight. See whichbudget.com for flight hops.

Some trains require reservations so You have to buy a reservation if you take that specific train. Trains are seldom full and there’s usually another train in an hour if one is full, so I only buy a reservation if the specific train requires one. Train stations, as Don states, are the cheapest places yo buy reservations.

If you’re willing (and able) to buy tickets in advance from the individual national rail company websites you can probably find specials that will be cheaper than a railpass for this trip. Here are the links for the websites: http://www.eurotrip…. Some of these sites don’t sell international tickets (one European country to another), others don’t take North American issued credit cards, e-tickets are not available for all trains and some tickets must be picked up in a specific country—— total result of this is that you will have to commit to advance purchase of non-refundable tickets and do a fair amount of work, and have a little luck, but if you’re successful, point to point tickets may be cheaper than a rail pass.