The text seeks to analyse the circumstances of the private operator's entry to the line in detail and, in particular, the circumstances and reasons for its exit. After an initial literature review, we describe the situation on the passenger rail transport market in Slovakia, especially the position of the incumbent and the introduction of a non-standard government measure: free fares for students and seniors. Then, we analyse in detail the situation that occurred on the Bratislava–Košice line after RegioJet's entry, especially the development of fares and changes in timetable and the number of services. After a short discussion of the results, we make conclusions and recommendations for further research.