Bavarian State 0-10-0 Locomotives in Germany

Class 5/5 / BR 57.5 (Locobase 10817)

Data from Christian Lindecke's Lokodex website ([], last accessed 27 October 2009). See also "Balanced Compound Freight Locomotive, Bavarian State Railways," Railway Master Mechanic, Vol XXXVI, No 4 (April 1912), pp. 145- as well as the Maffei advertisement promoting its appearance at the 1911 Turin International Exposition, which appears at []

This rugged, powerful design was required to ascend grades of 1-1.1% at a minimum speed of 15-16 mph (25 kph). It was a well-balanced and equalized design that could reach 60 kph (37 mph) on level ground with heavy trains.

Steam admission was simplified by simply enormous piston valves of diameters measuring 390 mm (15 1/4") for the HP cylinders and 425 mm (17 3/4") for the LP side. The real novelty lay in the provision of a annular receiver that served both pistons on a side. Note that the stroke for the LP cylinder ran 30 mm longer than did that of HP cylinder.

A similar arrangement from Baldwin -- the Vauclain compound system -- did not vary strokes as this setup did.

The RMM report notes several advantages of such an arrangement: "Two simple steam pipes suffice, however, with the new valve. The simplicity realized is considerable. Mechanically there is a gain represented by the reduction of four valve motions and valves to two. Not only does this save in the matter of first cost, but obviously there is a saving due to the reduction in the weight and frictional resistance of the moving parts. Again, receiver pipes are done away with, and the parts in the smoke-box are reduced. Thermally, the arrangement steams-jackets part of the valve chest and the interior of the valve itself, the steam pressure that is constantly maintained therein being from one-fourth to one-third of the initial pressure of the first expansion."

The design proved to be quite powerful and successful and the K Bay ordered 80 more to a a somewhat larger design in 1923-1924; see Locobase 15204.

Class 5/5 / BR 57.5 (Locobase 15204)

Data from Albert Gieseler's website at [] . Maffei delivered 40 in 1923-1924.

Locobase 10817 describes the 1911 design that the K.Bay.St put into service on 1.1% grades pulling heavy freights. After Maffei delivered the second batch in 1920, the builder and the railway tweaked the design. First to go were the annular piston valves and stroke lengths that differed from HP to LP cylinders. Cylinder stroke was equal for all four cylinders and the cylinder diameter increased. Then taking the firebox as it was and the boiler's diameter as it was, Maffei swapped out 30 tubes in favor of four more superheater flues.

Although combined heating surface dropped by about 3%, the superheater ratio increased and the increased cylinder volume led to a higher starting tractive effort.