The only AA I

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...

of the

Royal Bavarian State Railways The Royal Bavarian State Railways (''Königliche Bayerische Staats-Eisenbahnen'' or ''K.Bay.Sts.B.'') was the state railway company for the Kingdom of Bavaria. It was founded in 1844. The organisation grew into the second largest of the German ...

(''Königlich Bayerische Staatsbahn'') was built by the firm of Krauss in 1896. It had been designed by chief mechanical engineer, Richard von Helmholtz, as a 4-2-2-2 tender locomotive. The engine was largely based on the

Bavarian B XI The Class B XI engines of the Royal Bavarian State Railways (''Königlich Bayerische Staatsbahn'') were built between 1895 and 1900 by the firm of Maffei for deployment in Bavaria. The first delivery comprised 39 vehicles with two-cylinder, s ...

, but the driving and

running gear In railway terminology the term running gear refers to those components of a railway vehicle that run passively on the rails, unlike those of the driving gear. Traditionally these are the wheels, axles, axle boxes, springs and vehicle frame of a ...

was modified. The second coupled axle was replaced by a fixed

carrying axle A carrying wheel on a steam locomotive is a wheel that is not driven; i.e., it is uncoupled and can run freely, unlike a coupled or driving wheel. It is also described as a running wheelWörterbuch der Industriellen Technik, Dr.-Ing. Richard Erns ...

, and a dolly axle (''Vorspannachse'') added between the

bogie A bogie ( ) (in some senses called a truck in North American English) is a chassis or framework that carries a wheelset, attached to a vehicle—a modular subassembly of wheels and axles. Bogies take various forms in various modes of transp ...

and driving axle. This could be lowered by a pressure cylinder and was driven by an auxiliary engine with two cylinders. Despite her high maintenance requirement, she was economical to run due to her low steam consumption. In 1907 she was rebuilt after an accident into a 2'B h2 locomotive and redesignated as a Class P 2/4. She was taken over by the Deutsche Reichsbahn and run under operating number 36 861. She was the last Bavarian 4-4-0 locomotive to be retired in 1933. The engine was equipped with a Bavarian 3 T 14.5 tender.

References

* * {{DEFAULTSORT:Bavarian Aa I 4-4-0 locomotives AA I Standard gauge locomotives of Germany Krauss locomotives Railway locomotives introduced in 1896 4-2-2-2 locomotives 2′B h2 locomotives Passenger locomotives

See also

References