The Royal Saxon State Railways grouped all uncoupled locomotives under the designation VIa, i.e. the types that only had one driven axle. As a rule, these were express locomotives with an 2-2-2 wheel arrangement, which is discussed in more detail here.
The majority of these were 40 engines which were procured between 1848 and 1868 in some significantly different versions for the Leipzig-Dresden railway. Another three were built in 1861 and 1862 for the Eastern State Railway in Saxony. Since the locomotives were manufactured by Borsig and Hartmann, they were distinguished by the designations B VIa and H VIa. The Borsig machines were preceded by two from 1849, which only had a wheel diameter of 1,524 mm and a cylinder diameter of 330 mm.
Distinguishing features were the firebox with a rectangular cross-section and the inside frame, because most locomotives at that time had outside frames. The appearance of the wheels earned them the nickname “spinning wheels”. A special feature that other early locomotives also had was a Kirchweger type exhaust steam condenser. The exhaust steam from the steam chests was fed through a pipe into the tender and directly into the water to heat it. However, this technology disappeared again a short time later, as the injectors that were soon introduced only worked with cold water and the steam introduced substances into the water that attacked the metal.
Some of the first examples were retired as early as 1868, when production of the last had just ended. Between 1873 and 1876, four were converted to the 0-4-2 wheel arrangement, with some retaining the tender and the others becoming tank locomotives. Despite their outdated design, the locomotives were able to last so long that in 1890 21 of the 43 engines were still in use. The last two were withdrawn in 1900 and 1902.
