The steam locomotive DRG Class 74, also called Prussian T12, a hot steam variant of the wet steam locomotive T 11, was first tested in 1902. From 1905 to 1921, a total of 1014 copies (DR 74 401-543, 545-1321) of this twelve-meter-long and 65-tonne locomotive were produced in the Union Foundry and at Borsig Berlin. Among the structural peculiarities of the series was the installation of the two-cylinder engine between the wheelset and the first coupling axle. The unusually long inlet and outlet pipes of the steam engine have their reason in this arrangement. To improve cornering performance, the DRG Class 74 steam locomotive was equipped with a Krauss-Helmholtz steering rack, a special drawbar connection between the coupling and running axles, which allows opposing movement of the two axles. Except in the passenger traffic of the Prussian state railways, which had at the 1000 pieces from the series 74 in enterprise, the powerful one (in the level could be moved nearly 300 t with 75 km / h, the maximum speed was with 80 km / h) but because of Too few boiler reserves not very very persevering locomotive among others used in the Reich Railway Alsace-Lorraine and the Halberstadt-Blankenburg Railway. In and around Berlin drove the T12 as predecessor of the later of the S-Bahn on the entire urban and ring course net.