The Langenthal-Jura Railway was a former railway company in Switzerland. It merged in 1958 with the Langenthal–Melchnau-Bahn to form Oberaargau-Jura Railways, which then operated the then still 11 km-long, metre-gauge LJB line from Langenthal to Niederbipp. After further mergers, the Langenthal–Oensingen railway line has been part of the Aare Seeland mobil (ASm) since 1999.

The Langenthal–Melchnau railway line is a metre-gauge line between Langenthal and St. Urban in Switzerland; it originally ran to Melchnau. It was built by the former Langenthal–Melchnau-Bahn. The line runs through the cantons of Bern and Lucerne and is now owned and operated by Aare Seeland mobil.