In the twenties, the Reichsbahn started to experiment with steam turbine locomotives with mechanical power transmission. The main reason was estimated coal savings of 20 to 30 percent. Additionally, they promised a smoother acceleration and the use of a condenser prevented the buildup of limestone in the boiler. They just needed a fan to generate draft in the boiler since there was no exhaust steam from the cylinders that could be used.

The first prototype was the T 18 1001 that was built in 1924 by Krupp with the support of Escher, Wyss & Cie. of Switzerland. It had a 2,000 hp Krupp-Zoelly turbine mounted laterally above the leading bogie that transmitted its power to a crank axle. With a booster valve, it could even generate 2,800 hp for a limited time. For reversing, there was a smaller second turbine. This one was later replaced by a starting and shunting turbine with a reversable gearbox. The condensation device was placed in the tender.

1001 was tested for some time and then used in regular service from Hamm depot. Compared to traditional piston steam locomotives, it saved about 25 percent of coal. According to “Die Lokomotive”, June 1930, the coal savings compared to the P 10 were even 40 percent. Additionally, the condenser meant that it only needed very few water refillings. It was used until 1940 and was destroyed in the war.

A second prototype numbered T 18 1002 was built in 1926 by Maffei. It was also a Pacific, but had a Ljungström turbine and the condenser was not mounted on the tender, but on the locomotive below the running boards. Also this locomotive was used in regular express service, but was stationed at Munich. When this one was retired in 1943, it became clear that it did not achieve considerable coal savings.