Don’t buy tickets online.  You’ll end up paying a lot more for them.  You can just buy P2P tickets a day or 2 before you’ need them.  Unless you need a night train reservation, you won’t have any problems getting what you’ll need (including tickets, suppliments and reservations).

If you arrive in a city, and have an idea of how long you want to stay, buy your tickets to leave then.  It’ll save you having to go back to the train station.

I have a question…. you say “unless you need a night train reservation” there shouldn’t be any problems… what if you DO need one? I’m gonna have a Eurail pass, but as far as I can tell I can’t reserve ahead of time online without paying in full…. I’m afraid to just roll up to a trainstation and be like “yeah, I sorta need a night train res for…. tonight!”

Why do you want to buy them on-line?  It’s easy to buy them at the station in Europe and it’s usually MUCH cheaper.  If the trip is within 1 country you can buy the ticket on-line ( at the regular price as opposed to the inflated price railpass websites charge) from the national rail company in that country (sncf.com for France, trenitalia.com for Italy, etc.).  If the trip is within Germany buy from http://reiseauskunft… You can sometimes buy international tickets that either start or end in Germany from that website.

Freicht:  same applies to reservations.  They are much, much cheaper to buy at the train station than to buy from a website.  While you can usually get reservations up to about an hour before train time, it’s best to buy them about a day in advance for day trains and 3 or so days in advance for overnight trains.  You can buy reservations for any train in Europe at most of the major rail stations, so you can buy all the reservations for your whole trip at once when you 1st arrive in Europe if you have a set itinerary.  If you want more flexibility use Nivid’s suggestion and buy the reservation you’ll need when you’re going to leave a city before you leave the train station when you arrive in that city.

Oh really? I didn’t know that… So if I landed in Stockholm, I could pay for reservations for within, say, Germany too? And THAT wouldn’t have extra fees? I guess it just seems counter-intuitive to me that it would cost more to reserve from one company’s website than it would to reserve at their competitor’s window, or whatever…

  I’ve not tried it in Sweden.  There may have extra fees, but they will be very minimal.   Sometimes there will be a separate “international” window.

Hmm good point