German Reichsbahn class 41
Polish State Railways Ot1
For fast freight service, the Reichsbahn chose the 2-8-2 wheel arrangement in order to be able to achieve the required power with an axle load of 18 tonnes. To increase the adhesive weight on main lines, the axle load of the drivers could be changed to 20 tonnes by switching the position of some bolts. With a driving wheel diameter of 1,600 mm, the approved top speed was 90 km/h. The boiler pressure was initially set at 20 bars, but had to be reduced to 16 bars because of the problems with the St 47 K alloy that became brittle over time. After the war, the Reichsbahn and the Bundesbahn fitted their class 41 locomotives with new boilers. The Bundesbahn withdrew the last coal-fired locomotives in 1971, but those which had been converted to burn oil and which were now designated class 042, remained in service until 1977. The East German Bundesbahn even used their locomotives until 1988. Today, a number are still existing, with a few still in working order.
Technical data
General
| Property | as built | reduced boiler pressure | rebuilt Bundesbahn | rebuilt Reichsbahn |
|---|---|---|---|---|
| Built | 1937-1941 | 1957-1961 | 1959-1960 | |
| Manufacturers | BMAG, Borsig, Esslingen, Henschel, Jung, Krauss-Maffei, Krupp, O&K, Schichau | RAW Zwickau, RAW Karl-Marx-Stadt | ||
| Wheel arrangement | 2-8-2 (Mikado) | |||
| Gauge | 1,435 mm (Standard gauge) | |||
Dimensions and weights
| Property | as built | reduced boiler pressure | rebuilt Bundesbahn | rebuilt Reichsbahn |
|---|---|---|---|---|
| Length | 23.91 m | |||
| Wheelbase | 12.05 m | |||
| Total wheelbase | 20.18 m | |||
| Empty mass | 92.6 t | |||
| Service mass | 101.9 t | 109.6 t | 103.2 t | |
| Adhesion mass | 70 t | 77.8 t | 78.8 t | |
| Total mass | 176.1 t | 166 t | 177.4 t | |
| Rigid wheelbase | 5.55 m | |||
| Axle load | 18.2 t | 19.4 t | 19.7 t | |
| Water capacity | 34,000 l | |||
| Fuel capacity | 10 t (coal) | 12,000 l (oil) | 10 t (coal) | |
Boiler
| Property | as built | reduced boiler pressure | rebuilt Bundesbahn | rebuilt Reichsbahn |
|---|---|---|---|---|
| Grate area | 3.89 m² | 3.87 m² | 4.23 m² | |
| Firebox surface | 15.9 m² | 21.22 m² | 21.3 m² | |
| Tube heating surface | 187.25 m² | 156.32 m² | 185 m² | |
| Evaporative heating surface | 203.15 m² | 177.54 m² | 206.3 m² | |
| Superheater surface | 72.22 m² | 95.77 m² | 83.8 m² | |
| Total heating surface | 275.4 m² | 273.3 m² | 290.1 m² | |
Power plant
| Property | as built | reduced boiler pressure | rebuilt Bundesbahn | rebuilt Reichsbahn |
|---|---|---|---|---|
| Driver diameter | 1,600 mm | |||
| Boiler pressure | 20 bar | 16 bar | ||
| Expansion type | simple expansion | |||
| Cylinders | two, 520 x 720 mm | |||
Power
| Property | as built | reduced boiler pressure | rebuilt Bundesbahn | rebuilt Reichsbahn |
|---|---|---|---|---|
| Power source | steam | |||
| Estimated power | 1,625 kW (2,209 PS) | |||
| Top speed | 90 km/h | |||
| Starting effort | 206.9 kN | 165.5 kN | ||
| Indicated power | 1,397 kW (1,899 PS) | 1,453 kW (1,976 PS) | 1,434 kW (1,950 PS) | |
Calculated values
| Property | as built | reduced boiler pressure | rebuilt Bundesbahn | rebuilt Reichsbahn |
|---|---|---|---|---|
| Factor of adhesion | 1 : 3.32 | 1 : 4.15 | 1 : 4.61 | 1 : 4.67 |
| Optimal speed | 48 km/h | 51 km/h | 53 km/h | |
| Power-to-weight ratio | 15.9 kW/t | 13.7 kW/t | 13.3 kW/t | 13.9 kW/t |
| Heating Surface Equivalent | 427.1 m² | 475.2 m² | 480.4 m² | |
| Cylinder volume/HSE | 1 : 716.04 | 1 : 643.58 | 1 : 636.58 | |
| Adhesive weight/Total | 1 : 1.46 | 1 : 1.41 | 1 : 1.31 | |
| Tractive force/Heating surface | 1 : 15.69 | 1 : 12.55 | 1 : 12.65 | 1 : 11.91 |
| Grate area/Heating surface | 1 : 70.79 | 1 : 70.62 | 1 : 68.58 | |
| Firebox/Tube surface | 1 : 11.78 | 1 : 7.37 | 1 : 8.69 | |
| Total/Superheater | 1 : 2.81 | 1 : 1.85 | 1 : 2.46 | |