The Brig-Furka-Disentis railway ordered ten rack locomotives from SLM while under construction, the first three of which were delivered directly to the construction sites. They were based on the HG 2/3 of the Visp-Zermatt Bahn, but had a significantly higher power thanks to superheated steam. The four cylinders worked in compound operation, with the gearwheels driven by the low-pressure cylinders and always operated together with the adhesion drive. With the electrification of the railway, the locomotives were retired there in 1940. One was sold to France and four to French Indochina (Vietnam). The latter four came back to Switzerland in 1990 and two of them are now running on the Furka mountain line after being refurbished. 