88957 – Class T12 Steam Locomotive (class 74.4-13)
Greater trainloads as well as a greater train density in Berlin's suburban traffic (but also elsewhere) required the building of a tank locomotive with three driving axles on the Prussian State Railways (KPEV) at the start of the 20th century. As early as 1902 the Union Casting Company in Königsberg delivered the first four 2-6-0T units of the class T 12 – at that time still designated as the T 10 – for test operations on the Berlin city, ring, and suburban lines. These locomotives were equipped with the new superheated steam technology and had Schmidt design smokebox super heaters for this. Mostly identical wet steam units, the class T 11, were built for purposes of comparison. Yet extended test runs proved the superiority of the T 12 with considerable savings in coal and water consumption, thus justifying its construction in the future.
From 1905 on, 41 additional superheated units were delivered, now as the T 12. Among other things, they had a lengthened smokebox, larger cylinder diameters, and a longer ventilation hatch. The final form of the T 12 had definitely been found starting in 1911. By 1916, Prussia's state railroad had already purchased 934 locomotives. Regular production deliveries underwent constant improvements up that time such as the installation of new safety valves, two-stage compressors, Kuhnsche crosshead guides, and surface pre-heaters. In addition, T 12 units went to the Imperial Railways in Alsace-Lorraine, the Lübeck-Büchen Railroad (LBE), the Halberstadt-Blankenburg Railroad (HBE), and in 1921 Borsig delivered another 40 units to the Berlin Regional Railroad Administration. All total 1,014 T 12 locomotives were put into service with Union, Borsig, Hohenzollern, and Grafenstaden participating in their construction. Borsig had the biggest share in this at 732 units.
In 1925, the DRG took over 899 locomotives with the road numbers 74 401-543 and 545-1300 in its final new designation plan. After the "Great Electrification" of the Berlin City Railroad lines, numerous units were superfluous there and went to railroad maintenance facilities all over Germany. There they earned a living in switching work and as road engines. Many locomotives were still in use in both parts of Germany after World War II too. Yet since the DB as well as the DR used their T 12 units mostly in switching work, the conversion to diesel reduced the roster relatively quickly. The last of the "Mohicans" on the DB was road number 74 1070 in Düren, which was retired on May 11, 1966. At about the same time the last T 12 units disappeared on the DR too. Three units were preserved for posterity with road numbers 74 1192 and 1230 in Germany as well as the former road number 74 1234 in Poland.