the Brünigbahn, Switzerland, 1961

The 74 km (46 mile) meter gauge Brünigbahn links Luzern with Interlaken in the Bernese Oberland. The line runs via Alpnachstad, Giswil, Meiringen and Brienz, and passes over the Brünig Pass, using sections of rack railway to overcome the gradients, but with most of the line operated by normal adhesion.

The line was opened in stages between 1888 and 1916, and was, between 1903 and 2004, the only narrow gauge line of the Swiss Federal Railways. It was electrified in 1941 and 1942, using the standard Swiss mainline 15 kV  16.7 Hz AC from overhead.

For the newly electrified line, Deh 4/6 class locomotives were built in the early 1940s, one of them in the pic above. These were Bo'2'Bo' type.  More info.

Today the line forms part, along with the Luzern–Stans–Engelberg line, of the Zentralbahn company.