Lowering your expectations before embarking on a journey with one of these might not be a bad idea. Most of the trains are past their sell-by date and the trip to Zagreb sometimes has you boarding a bus once inside Croatia in order to get to your destination. The journey from Belgrade is a bit weird too and arrives in Banja Luka at 10pm after eight hours in a stuffy carriage, and that's the only option unfortunately. But on the plus side the tickets are cheap and the ride should be trouble free, like most aspects of travel in this part of the world.