Two cogwheel steam locomotives in very similar paint scheme, but from different stages in the development of the system. The small 350 horsepower 0-4-2 HG 2/3 # 6 "Weisshorn" was built by the SLM 1902 for the Visp-Zermatt railway (VZ), it has two independent twin drives for the two cogwheels and the two adhesion axles. The control is done by the very seldom used "Belpaire" system. The large 800 horsepower HG 4/4 # 704 on the right was built in 1923 by the SLM for the cog railway Krongh Pha - Da Lat in Indochina (today Vietnam) and has never been used in Switzerland. It is a compound locomotive with separate drives on the 4 coupling axles (high pressure) and the two cogwheels (low pressure) according to the "System Winterthur". The two locomotives were assembled here in Realp, a double heading service on the rack is excluded.
