Rail Pass/Ticket Purchasing

If your dates and journeys are set in advance it is generally cheaper to purchase point to point tickets as far in advance as possible (usually 90 days in advance for SNCF) - the cheapest tickets sell out quickly.

For journeys on long-distance trains advance buying gives you huge discounts if you don't mind your ticket being tied to a specific date and hour (50 percent or more is no exception). Best bought directly with the relevant railway company. Most have payment by credit card and a pdf-document for printing at home.
Further practical information on www.ricksteves.com/travel-tips/transportation/trains/buying-tickets

If you are using TGV trains with a railpass in France, you have to commit anyway. You can't just rock up and hop on and wave your pass at the Train Manager.

Railpass holders must purchase reservations for a particular train on a particular day, and those reservations are often subject to a rather low quota. Sometimes you have to be flexible when getting railpass holder reservations.

The regular tickets, both walk up and discounted, include the reservation in the price of the ticket.

There have been instances where some passholders have turned up, found all passholder reservations gone, and had to buy a walk up price ticket to get on a train with a number of empty seats.

Exactly what train journeys are you planning to take? The particulars of buying are different for each.

Rail passes are not a good value for most travelers these days. There are exceptions, particularly if you're going to Switzerland, or if you value flexibility above saving money.

For fast trains in France, it's cheapest to buy in advance online, as long as you can commit to non-refundable and non-exchangeable. tickets. The same is true for some other countries' domestic tickets, such as Italy and Spain and the UK, and for most international routes. For some other routes, the price doesn't change, so you can buy them when you get there.

Rail Europe often marks up tickets - sometimes substantially. They also don't show all trains. Unless you have a special reason to use it, it's better to buy direct from the company operating the train, or resellers like Captain Train that don't mark up tickets.

Again, if you give us your routes, we can give more tailored advice. Once you tell us where you're going, we can give you all the nitty-gritty about your options.

The options vary by country and by speed of train, as well as the distance you plan to travel in one day. Rick’s Train Travel Time & cost Map gives you an overview of faster train travel times in hours, as well as regular (full-price) 2nd-class fares for those faster trains. But if you're ready to reserve online from home, significant advance-purchase discounts are available for fast trains in much of western Europe (not for slower, unreserved regional trains). Those same fast trains may or may not require a paid seat reservation with a rail pass.