In 1913 the BLS made a successful takeover of the Lake Thun railway (TSB) (Thun/Scherzligen–Interlaken–Bönigen), and became the operating company for three other companies in the area, the Bern–Neuchâtel railway (BN), the Gürbetal–Bern–Schwarzenburg railway (GBS) and the Spiez–Erlenbach-Zweisimmen railway (SEZ) adding some 130 kilometers to its system.