Data from Christian Lindecke's German locomotive website -- [], accessed 24 October 2006.
Two of the famed P8 class of Prussian Ten-wheelers were converted to short-tender locomotives in 1950 by Krupp. A Professor Moelbert of Hanover's technical university apparently combined the facts of hundreds of redundant P8s and the need for commuter-service power in suggesting the modification. The conversion involved adding a four-wheel truck (bogie) under the firebox.
The overhaul proved too expensive to pursue on any scale and the two locomotives remained alone in their class until they were retired ten years later
Principal Dimensions by Steve Llanso of Middle Run Media | |
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Class | BR 78 umbau |
Locobase ID | 7907 |
Railroad | Deutsche Bundesbahn |
Country | Germany |
Whyte | 4-6-4T |
Number in Class | 2 |
Road Numbers | DB 78 1001-DB 78 1002 |
Gauge | Std |
Number Built | 2 |
Builder | |
Year | 1951 |
Valve Gear | Heusinger |
Locomotive Length and Weight | |
Driver Wheelbase (ft / m) | 11.81 / 3.60 |
Engine Wheelbase (ft / m) | 57.61 / 17.56 |
Ratio of driving wheelbase to overall engine wheelbase | 0.20 |
Overall Wheelbase (engine & tender) (ft / m) | 57.61 / 17.56 |
Axle Loading (Maximum Weight per Axle) (lbs / kg) | 38,140 / 17,300 |
Weight on Drivers (lbs / kg) | 112,656 / 51,100 |
Engine Weight (lbs / kg) | 241,847 / 109,700 |
Tender Loaded Weight (lbs / kg) | |
Total Engine and Tender Weight (lbs / kg) | |
Tender Water Capacity (gals / ML) | 3168 / 12 |
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 5 / 5 |
Minimum weight of rail (calculated) (lb/yd / kg/m) | 63 / 31.50 |
Geometry Relating to Tractive Effort | |
Driver Diameter (in / mm) | 68.90 / 1750 |
Boiler Pressure (psi / kPa) | 174 / 1200 |
High Pressure Cylinders (dia x stroke) (in / mm) | 22.64" x 24.8" / 575x630 |
Tractive Effort (lbs / kg) | 27,287 / 12377.19 |
Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.13 |
Heating Ability | |
Tubes (number - dia) (in / mm) | |
Flues (number - dia) (in / mm) | |
Flue/Tube length (ft / m) | 15.42 / 4.70 |
Firebox Area (sq ft / m2) | |
Grate Area (sq ft / m2) | 27.76 / 2.58 |
Evaporative Heating Surface (sq ft / m2) | 1542 / 143.28 |
Superheating Surface (sq ft / m2) | 634 / 58.90 |
Combined Heating Surface (sq ft / m2) | 2176 / 202.18 |
Evaporative Heating Surface/Cylinder Volume | 133.45 |
Computations Relating to Power Output (More Information) | |
Robert LeMassena's Power Computation | 4830 |
Same as above plus superheater percentage | 6231 |
Same as above but substitute firebox area for grate area | |
Power L1 | |
Power MT |