Baden II d

In view of the increasing loads in express train service around the turn of the century, the Grand Duchy of Baden State Railways launched a tender for a heavy express locomotive, in which seven designs took part. The requirement was to transport trains weighing 200 tonnes up gradients of 0.33 percent at a speed of 100 km/h. The contract went to Maffei, which also later developed the express trains for Baden.

In 1902, at the time of delivery, they were the largest of their kind in Europe with an operating weight of around 75 tonnes, which rested on a chassis with the axle configuration 4-4-2 (Atlantic). They were powered by a saturated compound engine, the four cylinders of which all acted on the first coupled axle. In contrast to the later Maffei express locomotives, the frame was not yet designed as a bar construction, but as a plate frame, as was usual at the time. Due to the elongated firebox, the distance between the rear coupled axle and the trailing axle was very large. The latter was designed as an Adam's axle, since the ash pan would not have allowed space for a drawbar.

Due to the long wheelbase and a large driving wheel diameter of 2,100 mm, the locomotives were remarkably smooth running right from the start. During test runs in 1904 with a train of four cars, top and average speeds of 144 and 116 km/h were reached. The first was broken three years later by the Bavarian S 2/6, which was also a Maffei design, but unlike the II d it was only developed as a one-off for test purposes.

The first production batch of twelve engines was manufactured by Maffei and delivered in 1902, another came in 1905 from the Karlsruhe mechanical engineering company and comprised six units. After the First World War, a total of ten engines had to be handed over to France. This left only seven units, as one engine had to be scrapped as early as 1903 due to an accident. The locomotives that remained in Germany were still intended to be redesignated as class 14⁴, but they could not expect a long life due to their only two coupled axles and were therefore retired in 1925. The now French locomotives remained in service for another nine years.