The Tss 4 were the first 750-mm gauge steam locomotives to be equipped with the Klose drive system.

From 1899 the Tss 4s got company from number 42, a Tssd class Mallet tank locomotive.

More Tssd locomotives were procured for the Bottwartalbahn, which meant a departure from the maintenance-intensive Klose drive system.

Nevertheless, the three Tss 4 remained in service until the early days of the Deutsche Reichsbahn, even if in the 1920s the locomotives were often stored or under repair because of their worn out Klose drive.

The arrival in 1923 of the newer Saxon VI K sealed the fate of the Tss 4 on the mainline.

The three tank locomotives were derived from the Ts 4 and adapted to the gauge of 750 mm (2 ft 5+1⁄2 in).

They worked on the second axle, which was firmly located in the outer frame and which was designed without flanges.

The valve gear was of the Klose type and therefore had levers arranged according to the pattern of a double parallelogram.

There was a Ramsbottom safety valve that was initially located on the firebox inside the cab.