Bavarian AA-I / P 2/4

Bavarian AA I (later P 2/4) DRG Class 36.8

Numbers:	1400 DRG 36 861
Quantity:	1
Years of manufacture:	1896
Retired:	1933
Wheel arrangement:	4-2-2-2, later 4-4-0
Axle arrangement:	2'aA1 n2v, later 2'B h2
Rail gauge:	1,435 mm
Length over buffers:	16,570 mm
Service weight:	51.7 t
Adhesive weight:	29.8 t
Axle load:	14.9 t
Top speed:	90 km/h
Driving wheel diameter:	1,870 mm
Leading wheel diameter	1,006 mm
No. of cylinders:	2
Cylinder bore:	490 mm
Piston stroke:	610 mm
Boiler overpressure:	13 bar
Grate area:	2.26 m²
Superheater area:	26.85 m²
Evaporative heating area:	95.60 m²
Tender:	Bavarian 3 T 14,5
Water capacity:	14.5 m³

Lok History. Synopsis

The only AA-I steam locomotive of the Royal Bavarian State Railways (Königlich Bayerische Staatsbahn) was built by the firm of Krauss in 1896, with factory no. 3200. 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, but the driving and running gear was modified. The second coupled axle was replaced by a fixed carrying axle, and a dolly axle (Vorspannachse) added between the bogie and driving axle. This could be lowered by a pressure cylinder and was driven by an auxiliary engine with two cylinders. The equipment was operated from the driver's cab by two levers on the steering post, one of which controlled the steam supply to the auxiliary machine, the other the pressure cylinder. Both levers were so interdependent that the steam supply to the engine could only be fully opened after the loading of the dolly axle had been carried out, and vice versa the load could only be lifted after partial shut-off of the steam supply to the auxiliary power unit.If the dolly axle was slowly lowered onto the track, the sand spreader was activated automatically. The engine was equipped with a Bavarian 3 T 14.5 tender.

Despite her high maintenance requirement, she was more economical to run than the BXI due to her low steam consumption (6.97 kg / km vs 7.77 kg / km of the B XI). She was assigned to the Bw Munich, where it was deployed in the service plan of the B XI. In the process, it has transported express and passenger trains to various cities as well as the Orient Express from München to Simbach.

In 1907 she was rebuilt after an accident (30.11.1905 near Türkenfeld) into a 2'B h2 locomotive and redesignated as class B XII , then later P 2/4. The conversion was already planned for before the accident. It received cylinders of 490 mm and a stroke of 610 mm and also got a superheater. After the conversion, the coupling axes of the P 2/4 were fixed in the frame. The coupling wheel diameter was increased by 10 mm. The bogie wheels had a diameter of 1006 mm, the side play of the bogie was ± 25 mm. After the reconstruction and a short test in Munich, P 2/4 was assigned to BW Augsburg. Later, in summer of 1908, it was assigned to the Bw Simbach, where it remained until it was handed over to Bw Mühldorf in 1929. The reconstructed P 2/4 was nicknamed "Hirsch" (The Deer) because she was a very good and fast locomotive. The P 2/4 was able to pull trains from 240 to 250 t on the 10⁰/₀₀ slopes at 40 km/h, which corresponds to an output of about 650 HP. Even on level ground, she could still pull trains up to 300 t with 75 to 80 km/h. Because of its reliability she was often seen in front of the Orient Express, which then crossed Simbach.

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.

Lok Photos

This section is based on Bavarian AA-I. For full article and a list of authors please refer to the original Wikipedia article.
More resources:

Bayern Report, nº 6. Die Gattungen B X, B XI, AA I, S 2/5 Vaucl., CIV bis C VI, BB I, E I, E I Vaucl., und G 4/5 N. - Ludwig v. Welser, München, Eisenbahn Journal, ISBN 3-922404-94-4
Lokomotiven der Bayersichen Eisenbahnen. Band 1: Geschichte der Bayerischen Eisenbahnen. Beschreibungen der Scnellzug-, Personenzug- und Güterzuglokomotiven. - Lothar Spielhoff, München, Verlag Jürgen Pepke. 2009. ISBN 978-3-940798-13-8

H0 SCALE MODELS LIST (2-rail DC/DCC only, operating state before 1925 - Epoch I and IIa)
LOCOMOTIVE						MANUFACTURER
Class	Railway Company	Epoch	Operating Number	Operating Year	Livery	Manufacturer	Mft. Code	Issue Year	Analog/ Digital	Decoder	Lights	Sound	Smoke	Remarks
AA-I	K.Bay.Sts.B.	I	"1400"	1895	Green / Black	MICRO-METAKIT MICRO FEINMECHANIK	91001H 91001HL	1991	Analog	No	No	No	No
P 2/4	K.Bay.Sts.B.	I	"1400"	1907	Green / Black	MICRO-METAKIT MICRO FEINMECHANIK	na	2011	Analog	No	No	No	No	Prototype, never made it in production

Colour Codes

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