The Brienz Rothorn Railway (, BRB) is a tourist rack railway in Switzerland, which climbs from Brienz, at the eastern end of Lake Brienz, to the summit of the Brienzer Rothorn. The railway is 7.6 kilometres (4.7 mi) long, is built to 800 mm gauge ( gauge), and uses the Abt double lamella rack system. Unusual for Switzerland, the line is not electrified, and most trains are operated by steam locomotives.