As we boarded a night train headed to Belgrade, Serbia, we hoped for a smooth ride and plenty of sleep. The train was relatively empty so we found an empty cabin that we could stretch out on for the first leg. After three hours, around midnight, we had to transfer trains in Doboj, Bosnia, and Herzegovina (and transfer character sets - note the Cyrillic), and we were happy to find that we would again get our own cabin with space to sleep.