Tips for train travel from Budpest-Vienna-Prague

a. The advantage to buying now, is the opportunity to get discounts, but they are usually nonrefundable and not changeable, at least without a fee. If you have a set itinerary with hotel bookings, its easy to commit. If you are going seat-of-your-pants, you may not be able to commit, but you can always get seats at the least minute and pay full price. You can buy tickets at www.oebb.at. That is the Austrian Railway site. Tickets there can be bought and printed at home. You may be able to do Budapest to Vienna cheaper if you take trains requiring connections and buying with the Hungarian currency.
b. If you travel using the Austrian direct Railjet trains, Budapest-Keleti, Wien Hauptbahnhof, Prague hl.n. are the main stations that these trains use.

The fastest train between Amsterdam Centraal and Brussels Midi is the Thalys high speed train. Same deal here. Advance purchase tickets get discounts and are nonrefundable. www.thalys.com. It is also possible to take more time with slower local trains that require connections for less money, especially if buying at the station.

I wont pretend to be any expert on the subject, but I have ridden some trains in the region over the years. I arrive in a town and then as soon as convenient I go to the train station to purchase the next leg. No restrictions and some times small discounts since its a few days prior. If I were going to ride a train departing from Budapest I would go to the Hungary site to check the schedule: http://elvira.mavinformatika.hu/ The internet rate is 12 to 19 euro; but it is for a set train on a set date. There is a person very experienced with the internet purchase of Hungarian Train tickets that helps out on the Hungary RS Foru.

Budapest to Vienna is a direct trip with no transfers and can be as little as 3 hours. Don't get hung up on the Rail Jet trains on the Budapest to Vienna leg as the EC trains are as fast or faster. Just choose the fastest train in the time span you want to travel. Travel 2nd class as the advantage of 1st class is pretty negligible.

You would be best to make the Budapest leg on the 15th of July.

I seem to remember paying something in the neighborhood of 30 euro when I purchased the tickets at the station. I'm not going to complain about the difference. You will leave from Keleti station which is described by Fred as very tourist friendly. I agree. For more on Budapest, and more help on the trains you might post in the Hungary forum.

We just bought our tickets as we were leaving, April, 2014. Each was about a 3 hour train ride through a river delta. It wasn't especially interesting countryside, and the old trains' air conditioning didn't work that well--little hot inside. I don't know if 1st Class a/c works better, but it might be worth the higher fare if it is more comfortable.
You'll have to check online to see which train stations are being presently used. Vienna's main train station has been under major construction, and we left for Prague from a station about 1 1/2 miles west--down the tracks.
You're going to visit three absolutely great cities. I suggest taking one of the Free Walking Tours the first day, and take a Night Life Tour or Pub Crawl Tour with the same tour company. You'll have a ball and learn so much more about the city.

If this trip is coming up next week, and if the advance-purchase options are adding and stress or complexity that you don't need right now, then you can easily purchase tickets when you arrive or as you go. A train station (or some travel agencies) in Budapest will sell all of them. Among the three trains, the Thalys is generally the more expensive ticket (€80 per person for "semi-flex" fare in 2nd class) with more potential savings for advance purchase (and discounts for age 60+). In comparison, full fare, 2nd class on the Budapest-Vienna Rail Jet is only €37 per person.

"Budapest-Vienna Rail Jet"

RAIL JET sounds pretty fast, but they are generally 10 minutes slower than the EC trains on the Budapest to Vienna run. Why? Beats me. Also be careful you get a direct train. The good rides will be just under 3 hours. Last time I purchased thicket I believe that all trains heading the same route had the same price, so unless something has changed get the one that is most convenient and don't worry about what it is called. Again, best advice is to check the MAV website. If you have any questions call them. They have been good with me on the phone in the past.

BUT!!!! don't sweat it. Relax, enjoy, unwind. Its all going to be good. Just don't leave until the 14th.