GUWAHATI: The Northeast Frontier Railway (NFR) has extended and introduced special train services to manage increased passenger traffic during the summer rush. Train services of Dibrugarh–Kolkata (05932/05931) and Bhagalpur–Katihar (03407/03408) have been extended for additional trips in both directions. The Dibrugarh–Kolkata special will run from June 6 to July 25, while the return service will operate from June 8 to July 27 with existing schedules. The Bhagalpur–Katihar special will continue operations until June 4 in both directions with three additional trips as per the existing timetable. Additionally, one-way special trains will be operated on June 4 from Guwahati to Tirupati (05630) and Rangapara North to Vijayawada (05862) for a single trip each, a press release said.