For those who don't speak Bulgarian, the railway tickets indeed might be tricky to understand if you purchase them at the station. All information is printed in Cyrillic, so it's a powerful argument on why it's better to buy Bulgarian train tickets online.
Rail Ninja offers
you
the
main details about your journey in English (as well as several other languages) and allows you to book your tickets for up to 2 years prior to your rail trip! But if you happen to be on a spontaneous voyage and find yourself struggling at the station with no idea where to
go,
feel
free to ask a nearby local for help. Plus, Google Translate might be a great help in cases like that.