Is there a possibility to buy RZD sleeper place & ticket from Bulgaria to Czech Republic (the coach goes, according to rzd website, through Serbia, Hungary and Slovakia) on Bulgarian railway station?
Yep, don't see why not. However it will be rather pricey, since it's "global price" fare (e.g. Sofia to Ostrava should be 101,60 euro), much cheaper will be to travel with ZS/BDZ/MAV carriages in trains to which those RZD carriages are attached
Author