Prussian G 4²

After gaining experiences with double steam expansion in Prussia with the two omnibus locomotives from 1880 onwards, the G 4¹ was developed into the first series-produced engine with a compound engine. The resulting G 4² was a complete success and not only achieved much higher sales figures than its predecessor, but could also be sold to other railways.

A typical problem for compound steam locomotives was the starting behavior, because the high and low pressure cylinders could only be flown through in one order with normal piping. Under these circumstances, a special starting device had to be developed with which the locomotives could start moving even if the wheels were in an unfavorable position. After solving this problem, the G 4² proved to be very economical, making it particularly suitable for longer runs with heavier freight trains and was mass-produced in large numbers. Since conventional simple locomotives were better able to hold their own on lines with multiple stops, the G 4¹ continued to be produced in smaller numbers.

780 examples were completed for the Prussian State Railways, which were later supplemented by more after acquisitions of private railways. These included the East Prussian Southern Railway, the Werra Railway and the Royal Prussian Military Railway. Larger numbers were also built for the Grand Duchy of Oldenburg State Railways and the Imperial Railways in Alsace-Lorraine, with numbers of 27 and 57 respectively. Other customers with smaller numbers were the Lübeck-Büchener Eisenbahn and the Mecklenburg Friedrich-Franz-Eisenbahn.

As with its sister model, an extraordinarily small number of only six had to be handed in as reparations after the World War, but their number was reduced very quickly in the following years. 295 were to be taken over by the Reichsbahn as numbers 53 001 to 53 295, but in 1925 only 24 were left. The last ones were decommissioned in 1930, if one disregards a few incorporations of railways that were taken over later.