For some lines where the axle load of the standard G 7 variants was too high, the G 73 was designed with an additional leading axle, what gave a 2-8-0 wheel arrangement. It still had the same compound cylinders as the G 72, but the additional axle allowed to use a somewhat heavier boiler, while retaining the lower axle load. Between 1893 and 1895, Hanomag built only 15 since many lines had meanwhile been upgraded for heavier axle loads, allowing to use the G 72.
In World War I, there was a new requirement for freight locomotives with a low axle load. So Maffei, Krauss and Esslingen produced a new batch of 70 which were directly delivered to the army railways. These now had a feedwater heater and a boiler pressure of 14 instead of 12 bars. After the war, 23 were used in Poland as Tr1 and 17 in Belgium as HL 73. In Germany, eleven were taken over by the Reichsbahn, five by the MFFE and four by the LBE. After World War II ended, none were still in service.