The Aussig-Teplitz railway was built in northern Bohemia in 1858 primarily to transport the lignite mined there. After the first passenger locomotives had been delivered by Borsig, in 1859 the first freight locomotive with a 0-6-0 wheel arrangement was also delivered by Borsig. Since this locomotive was classified as too powerful for its time, initially only four more units were ordered between 1864 and 1867, which, however, were supplied by the Wiener Neustadt locomotive factory Sigl. They were classified in type IIa and remained the only ones of their kind at ATE until 1870. Only after the extension of the main line did the construction of 32 further units begin at Hartmann in Chemnitz and at Sigl, which became class IIb.

Characteristics of the locomotives were the disc wheels and the outside frame. The cylinders were on the outside under the frame, while the valve gear was on the inside. Although the lignite available on site was burned, a firebox placed between the wheels was large enough. Since increased sparks had to be expected from the lignite, all ATE locomotives were fitted with a large spark-arresting chimney.

The locomotives were mainly used to transport lignite and fulfilled this role well into the twentieth century. After Bohemia became part of the newly founded Czechoslovakia in 1918, the ATE initially continued to exist. Only in 1924 it was nationalized and incorporated into the CSD. At that time, 36 of 37 examples were still running, which now became the class 320.1. They eventually retired from service by 1938.