Nitish Kumar is pressing the Congress-led central government to give "a special status" to help Bihar develop economically.
Nitish Kumar, accompanied by hundreds of slogans-shouting party leaders and supporters, walked from his official residence here to the Gandhi Maidan to stage a day-long sit-in.
Police said JD-U supporters halted over two dozen long-distance trains, stranding passengers at Patna, Gaya, Jehanabad, Bhagalpur, Nalanda, Muzaffarpur, Madhepura, Saharsa and Darbhanga railway stations.