As already described for the G 8, this did not have a particularly high output due to the limitation of the axle load to just over 14 tonnes. Therefore, the G 81 was developed on the basis of this, which was only suitable for main lines, but was significantly more powerful.
Initially, this variant was only referred to as the “augmented standard design” until it was given a separate designation. Between 1913 and 1921, 5,155 examples were built, making them the most numerous Länderbahn steam locomotive. 4,958 of these went to the Prussian State Railways, the rest were ordered by other railways at home and abroad.
The most important difference to the G 8 was a larger boiler, the pressure of which was also increased from 12 to 14 bars. The cylinders had the same dimensions as the last series of the predecessor, but could convert more power due to the higher pressure. Overall, the indicated power was increased from 1,100 to 1,260 hp, while the service mass and thus the adhesive weight increased by more than ten tonnes.
Sectional drawing with dimensions
Die Lokomotive, January 1916
The Reichsbahn took over 3,111 locomotives from Prussia and ten from the Reichseisenbahnen Alsace-Lorraine, which were classified together in the class 5525-56. Twelve more from Mecklenburg became the class 5558. Between 1934 and 1941, 691 locomotives were fitted with a leading axle, which improved running smoothness and allowed a top speed of 70 km/h. These became the class 562-8.
As with other classes, more came to the Reichsbahn in 1935 after the Saarland was incorporated into the Reich, just as some engines returned from Poland during World War II.
After the war, a total of around 1,000 pieces were taken over by the two German railways. In 1968 there were still 200 of these. They were therefore given the computer-compliant class number 055 on the Bundesbahn, but were also retired by the end of 1972. In the last years, these locomotives have mainly been used for shunting services, as they were too slow for freight trains on main lines, but also too heavy for many branch lines.