The first compound locomotives that the VSB procured were ten express locomotives from the years 1890 to 1897. They had the wheel arrangement 2-6-0 and were designated by the VSB as A3T, but are better known under their later SBB designation B 3/4.
After the first batch of ten locomotives, five more were built from 1900. Not only were the cylinders larger, but they also received a new boiler. This had higher pressure and a larger firebox at the expense of the tube heating surface. The first series was phased out between 1913 and 1924, the last disappeared in 1929.