The Altenbeken–Kreiensen railway is part of a former long-distance route in Germany from the Ruhr area via Altenbeken, Höxter-Ottbergen, Holzminden, Kreiensen and Seesen towards Berlin.

To connect with the Brunswick area the line bypassed the town of Einbeck with two tunnels and a long climb.

The line lost importance because more traffic shifted to the north-south direction over the decades after 1945 as a result of the division of Germany.

The Paderborn–Holzminden–Kreiensen service ended with the handover of passenger operations between Paderborn and Holzminden on the line to NordWestBahn in December 2003.

The eastern section was operated every two hours by Deutsche Bahn with Alstom Coradia LINT diesel single-units.

With the timetable change on 15 December 2013, both services were combined as RB 84 (Paderborn–Höxter-Ottbergen–Kreiensen) in the OWL diesel network and operated by NordWestBahn.