Having difficulty booking tickets from Prague to Warsaw. Neither the Czech railway site nor the Polish booking agency seems to offer Etickets or any way to receive paper tickets in the US.
The Man in Seat 61 says that the Czech site can do it; see his advice at https://www.seat61.com/international-trains/trains-from-Prague.htm#Prague-Warsaw. If you're booking departures that require one connection, it might help to break up the pieces. If it doesn't work for you, then I'd buy the tickets in Prague at the train station or a travel agency.
US agents don't have a "direct connection" to these railway's advance discounts, if any. They only sell full-fare tickets, which go through a few middle-men and currency exchanges.
There are three direct trains from Prague to Warsaw. The first one leaves Prague Main Train Station at 6:22 and arrives in Warszawa Centralna at 14:27. If you buy ticket for tomorrow it cost 1045 czk = US$45.82 If you buy it let's say for August 16th it is 509 czk = US$ 22.32. Go to:
http://www.idos.cz . You choose the train, it says buy and it tells you the price. Then the site automatically changes to cd.cz, you pay and print your ticket.