BernLötschbergSimplon

Bern-Lötschberg-Simplon-Bahn, commonly abbreviated BLS, was a Swiss railway company that operated the standard-gauge line linking Bern with the Lötschberg and Simplon corridors. The company's primary purpose was to develop and operate a north–south Alpine transit route connecting the Swiss capital with the Valais and, via the Simplon Pass, Italy. The system included the Bern–Lötschberg–Simplon route through the Bernese Oberland and valley regions.

Historically, BLS arose from earlier regional lines that sought a robust alpine corridor. The Lötschberg Tunnel, a key alpine crossing on the route, opened in 1913, establishing a long-standing mountain connection between Bern and the Valais. The Simplon Tunnel, another major component of the corridor, opened in 1906, providing a direct link to Italy. Together these tunnels positioned the Bern–Lötschberg–Simplon line as one of the principal Alpine transits in Switzerland, complementing other routes such as the Gotthard corridor.

In the late 20th and early 21st centuries, Swiss rail restructuring led to a reorganization of the BLS. In 2003–2004 the Bern-Lötschberg-Simplon-Bahn consolidated into a corporate form known as BLS AG, a joint-stock company that continued to operate the network. The BLS group remains a major operator of passenger and freight services in western Switzerland, with the Lötschberg line interfacing with the national network. The Lötschberg base tunnel, opened in 2007, forms a high-speed alternative on the same corridor, while the historic mountain route continues to serve regional and freight traffic.