Prussian T 9³

Since there was not much confidence in the running characteristics of the 0-6-2 chassis of the T 9¹, 235 examples of the T 9² with a wheel arrangement of 2-6-0 had already been bought between 1892 and 1900. The T 9³ was a heavier development that was procured in large numbers from 1900 onwards.

From the outside, the most distinguishable feature was the boiler now being situated higher than before. Despite a smaller grate and a slightly smaller evaporative heating surface, the power could be increased by 10 hp. The cylinder diameter was increased by 20 to 450 mm, while the piston stroke remained at 630 mm. The chassis has also been improved and the leading axle wasn't longer designed as a simple Adams axle. Now the leading axle and the first driving axle formed a Krauss-Helmholtz bogie, which allowed to increase the maximum speed to 65 km/h.

The Prussian State Railways alone procured 2,052 machines, including eight more from the East Prussian Southern Railway. There were also 132 for the Reichseisenbahnen Alsace-Lorraine and ten for the Mecklenburg State Railways. The Reichsbahn was able to take over 1,544 engines and classified them as 91 303 to 91 1844 and 91 2001 to 91 2010. In the period that followed, their number hardly decreased, they were even filled up during the Second World War with locomotives which went to Belgium after the First World War and had now returned.

After the war, the engines went to both German railway administrations, where their number quickly decreased due to the often insufficient power and speed. In the west their service ended in 1964 and in the east in 1970. In recent years, the engines of the Reichsbahn were mainly used as industrial locomotives. In other countries, the remaining engines where operated as ÖBB series 691, CSD series 335.1 and PKP TKi3.