I am trying to make reservations on the night train from Split to Zagreb then onto Vienna. Having trouble finding a website to do this. Have emailed back and forth but still confused. We have done a lot of train travel in Western Europe but first time in Eastern Europe. Any help would be appreciated,
Go to Tripadvisor and post on the train forum.
Also look here:
Are you really sure you want to do a night train?
You can buy those two separate, reserved train tickets at train stations and some travel agencies in Europe or for home delivery before you go through the link at the top of http://www.ricksteves.com/travel-tips/transportation/trains/buying-tickets. They go on sale about two months in advance of the travel dates.