In 1870, the Toggenburg Railway received three 0-6-0 tank locomotives from Krauss. They were ordered by the VSB, which was the operator of the TB and were named “Hülftegg”, “Yberg” and “Churfirsten”. The water was carried between the frames and the Allan valve gear was situated on the outside. With a diameter of 1,210 mm, the drivers looked relatively large for these small locomotives.

The first, domeless boilers were later switched for a larger one that had a dome. These locomotives did not only work on the TB line, but also on the VSB network. From 1885 they were designated series V, what was changed to III in the following year. Only one year later, they were again renamed to E3. After their withdrawals in 1909 and 1912, two were used as works locomotives by the SBB until 1929 and 1931.