For travel in most countries, tickets can be purchased online, by telephone, from a travel agent or other independent booking agent, from a kiosk, from an agent at the station, and, in limited circumstances, on board the train.
A passenger ordering online should print the reservation information, which will be redeemed for tickets at the station. Do not board a train with only a printed reservation, unless that is the explicitly stated policy.
Travelers purchasing tickets from an agent or automated kiosk will receive printed tickets or passes. These are the tickets and must not be lost.
Rail pass holders have freedom to choose when and where they travel and do not need to purchase tickets for individual trains.
In some countries, a seat or sleeping car reservation must be made in addition to the ticket purchase. A rail pass holder often must make a reservation in order to secure a spot on the train; the pass itself is not enough to guarantee passage.
Worldwide, railway companies are unforgiving when it comes to lost tickets, even those purchased online. Amtrak claims that "lost tickets are lost money," and most railway companies require a traveler to purchase new tickets until a refund request can be processed (often taking months).