The only narrow gauge railway operated by the SBB, the Swiss national railways, the SBB Brünig Railway is a metre gauge, rack and adhesion railway using the Riggenbach rack system to overcome grades of up to 12%. It was the first combined rack and adhesion railway in Switzerland.
The line's electrification was completed in 1942, and it uses 15 kV alternating current at a frequency of 16 2/3 Hz. The total route distance is 74 km, stretching between Lucerne in the north and Interlaken Ost in the south, via Meiringen, linking Lucerne with the scenic Bernese Oberland area.
In a partnership with the standard gauge BLS Lötschberg Railway and the narrow gauge Montreux-Oberland Bernois Railway MOB, it does business as the Golden Pass Line, with through ticketing.
It also connects with the Lucerne-Stans-Engelberg Railway (LSE) at Hergiswil, the Meiringen-Innertkirchen Railway (MIB) at Meiringen, and both the rack Brienz Rothorn Railway (BRB) and the Bernese Oberland Railways (BOB) at Interlaken Ost.
Just like the standard gauge SBB equipment, locomotives and cars are painted in either bright red or a deep green (the locomotives generally red) with the white SBB double arrow logo and the word 'Brünig' in white.