In 1999, it merged with the Biel–Täuffelen–Ins railway (Biel-Täuffelen-Ins-Bahn; BTI), the Solothurn-Niederbipp Railway (Solothurn-Niederbipp-Bahn; SNB) and the Oberaargauische Automobilkurse (OAK) to form Aare Seeland mobil (ASm), which now operates the 22 km-long, metre-gauge line from Langenthal to Niederbipp and Melchnau respectively.

The Oberaargau-Jura-Bahnen (OJB) (Melchnau-Langenthal-Niederbipp) based in Langenthal was formed in 1958 from the merger of the Langenthal-Jura-Bahn (LJB) and the Langenthal-Melchnau-Bahn (LMB).

Passenger services to Melchnau were replaced by buses, which allowed a significant reduction of travel time as they used a more direct route to Langenthal.

An early sign of the later merger was a formal agreement that was contracted on 5 April 1984 between the BTI, the OJB, the SNB, the Oberaargauischen Automobilkurse (a bus company; OAK), the Ligerz-Tessenberg-Bahn (a funicular railway; LTB) and the Bielersee-Schiffahrts-Gesellschaft (Lake Biel Ferry Company; BSG) to form Oberaargau-Solothurn-Seeland-Transport (OSST).

The OSST partners, BTI, RVO, SNB and OAK, were merged into Aare Seeland mobil (ASm) in 1999.

The SNB, which was opened on 9 January 1918, included another transporter wagon yard, located in Niederbipp, which was also used by the LJB.

A dual gauge track was laid in the shared facility in Niederbipp, which was commissioned on 7 March 1970 and runs along the SNB to the Oberbipp siding to a tank farm.

The new program was called Star (for: Schmalspur-Triebzug für attraktiven Regionalverkehr—"narrow-gauge multiple unit for attractive regional transport").