Bavarian S 2/5 (Vauclain)

In order to gain experience with steam locomotive designs from the USA, the Bavarian State Railways ordered four locomotives from Baldwin in 1899 and 1900. These were the two type E I Consolidations and the two type S 2/5 Atlantics. What both had in common was the four-cylinder Vauclain compound engine and the bar frame. The S 2/5 was based on the Milwaukee Road class A-1, but to save weight the drivers were made smaller by six inches.

The special feature of the Vauclain drive was that all four cylinders were outside the frame and were easily accessible. Although this design did not become established in Europe, the Bavarian State Railway adopted the bar frame for all later four-cylinder locomotives. This made maintenance of the cylinders located within the frame easier. The bar frame was later also used on the standard locomotives of the Reichsbahn, even though in principle only a few southern German influences were allowed on these. The two S 2/5 remained in service between Munich and Salzburg for more than 20 years, but were decommissioned in 1923 and were therefore no longer renumbered as Reichsbahn class 14.