Bavarian BB II
German Reichsbahn class 987
The problem on the Bavarian local railways was that there were very tight curves in some cases, and there were also many inclines and therefore increasingly more powerful locomotives were needed for the ever increasing requirements. For this reason, the BB II was developed, whose coupled axles were not in a common frame for better running characteristics in curves.
As a Mallet-type tank locomotive with only two axles each in the frame and in the bogie, it was ideal for the winding lines. Due to the lack of carrying axles, the running properties at line speed proved to be insufficient. In addition, the locomotive tended to slip and was therefore not always able to fully utilize its power.
Production consisted of a batch of 29 machines between 1899 and 1903 and a second batch from 1908, in which only two examples were made. The latter were slightly longer and heavier than the previous ones. They were all taken over by the Reichsbahn in 1925 and designated as class 987. However, due to the shortcomings described, most of them were already retired in the 1930s. The remaining ones were sold to various works railways from around 1940, where the smooth running of the machines was not a problem. The former 98 727, which was sold to Südzucker AG in 1943, is now being kept operational by the Darmstadt-Kranichstein Railway Museum. Due to the advertising character of its former operator, it was nicknamed “Zuckersusi” (“Sugar Susi”).
Technical data
General
- Built
- 1899-1908
- Manufacturers
- Maffei
- Wheel arrangement
- 0-4-4-0T (Four Coupled Mallet)
- Gauge
- 1,435 mm (Standard gauge)
Dimensions and weights
- Length
- 10.01 m
- Wheelbase
- 5.20 m
- Service mass
- 42.6 t
- Adhesion mass
- 42.6 t
- Rigid wheelbase
- 1.60 m
- Axle load
- 10.7 t
- Water capacity
- 4,300 l
- Fuel capacity
- 2 t (coal)
Boiler
- Grate area
- 1.4 m²
- Evaporative heating surface
- 67.7 m²
- Total heating surface
- 67.7 m²
Power plant
- Driver diameter
- 1,006 mm
- Boiler pressure
- 12 bar
- Expansion type
- compound
- Cylinders
- four, HP: 310 x 530 mm and LP: 490 x 530 mm
Power
- Power source
- steam
- Indicated power
- 280 kW (381 PS)
- Top speed
- 45 km/h
- Starting effort
- 73.8 kN
- Starting effort simple
- 88.5 kN
Calculated values
- Factor of adhesion
- 1 : 5.67
- Optimal speed
- 23 km/h
- Power-to-weight ratio
- 6.6 kW/t
- Adhesive weight/Total
- 1 : 1.00
- Tractive force/Heating surface
- 1 : 22.76
- Grate area/Heating surface
- 1 : 48.36