Bavarian AA I

The only AA I steam locomotive of the Royal Bavarian State Railways (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, 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 engine was equipped with a Bavarian 3 T 14.5 tender.

BuilderKrauss

BuilderKrauss

Build date1896

Total produced1

Quick facts Bavarian AA Ilater P 2/4 DRG Class 36.8, Type and origin ...

Bavarian AA I later P 2/4 DRG Class 36.8
Type and origin Builder Krauss Build date 1896 Total produced 1
Specifications Configuration: ​  • Whyte 4-2-2-2, later 4-4-0 Gauge 1,435 mm (4 ft 8+1⁄2 in) Leading dia. 1,006 mm (3 ft 3+5⁄8 in) Driver dia. 1,870 mm (6 ft 1+5⁄8 in) Length: ​  • Over beams 16,570 mm (54 ft 4+1⁄4 in) Axle load 14.9 t (14.7 long tons; 16.4 short tons) Adhesive weight 29.8 t (29.3 long tons; 32.8 short tons) Service weight 51.7 t (50.9 long tons; 57.0 short tons) Water cap. 14.5 m3 (3,200 imp gal; 3,800 US gal) Boiler pressure 13 kgf/cm2 (1.27 MPa; 185 lbf/in2) Heating surface: ​  • Firebox 2.26 m2 (24.3 sq ft)  • Evaporative 94.60 m2 (1,018.3 sq ft) Superheater: ​  • Heating area 26.85 m2 (289.0 sq ft) Cylinders 2 Cylinder size 490 mm (19+5⁄16 in) Piston stroke 610 mm (24 in)
Performance figures Maximum speed 90 km/h (56 mph)
Career Numbers K.Bay.Sts.E.: 1400 DRG: 36 861 Retired 1933

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Despite high maintenance requirements it was economical to run due to low steam consumption. After an accident in 1907 it was rebuilt into a 2'B h2 locomotive and redesignated Class P 2/4. It was taken over by the Deutsche Reichsbahn and renumbered 36 861. It was the last Bavarian 4-4-0 locomotive to be retired in 1933.