Planning July prague Vienna romania trip. Thinking take night train Vienna to Brasov and then work east to Bucharest later and fly home from Bucharest. Assume 2nd class sleeper train. Have Me Wife and 9 and 11 year old girls (2 adults 2 kids) There appear to be two trains one requiring a switch one not. early vs late. Can I book in advance? What are the fees including supplemental? Is there a way to get a compartment/section for just the four of us?