2-8-4 Steam Locomotives in Bulgaria

Bulgarian State


Class Details by Steve Llanso of Sweat House Media

Class 36 (Locobase 1598)

[] (viewed 18 July 2003). See also "2-8-4-Bulgaria" in Wikipedia at [], last accessed 18 January 2026. Tube diameters are inner dimensions. Works numbers were 2272-2281 in 1943.

Wikipedia explains the the BDZ--then an ally of the Third Reich--ordered 20 of these eight-coupled tank locomotives in 1941. They planned to operate them on local passenger service. The design's relatively low axle loading combined with "their large coal and water capacities made the new class suitable for a wider range of duties, if required."

Because of the intensity of the titanic battles between Germany and the Soviet Union, Krupp could only produced ten. After World War II, ended the BDZ used the 36s not only for local trains but also for trains enroute to Turkey hauling international expresses.

Their mere existence and paid-for status combined with their youth and well-dimensioned design kept them in service until the 1970s

Principal Dimensions by Steve Llanso of Middle Run Media
Class36
Locobase ID1598
RailroadBulgarian State
CountryBulgaria
Whyte2-8-4T
Number in Class10
Road Numbers36.01-10
GaugeStd
Number Built10
BuilderKrupp
Year1943
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)19.03 / 5.80
Engine Wheelbase (ft / m)39.70 / 12.10
Ratio of driving wheelbase to overall engine wheelbase 0.48
Overall Wheelbase (engine & tender) (ft / m)39.70 / 12.10
Axle Loading (Maximum Weight per Axle) (lbs / kg)36,707 / 16,650
Weight on Drivers (lbs / kg)138,009 / 62,600
Engine Weight (lbs / kg)244,558 / 110,930
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)2376 / 9
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 8.80 / 8
Minimum weight of rail (calculated) (lb/yd / kg/m)58 / 29
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)61 / 1550
Boiler Pressure (psi / kPa)235 / 1600
High Pressure Cylinders (dia x stroke) (in / mm)17.32" x 27.56" / 440x700 (3)
Tractive Effort (lbs / kg)40,609 / 18419.95
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.40
Heating Ability
Tubes (number - dia) (in / mm)127 - 2.126" / 54
Flues (number - dia) (in / mm)38 - 5.63" / 143
Flue/Tube length (ft / m)13.62 / 4.15
Firebox Area (sq ft / m2)166.84 / 15.50
Grate Area (sq ft / m2)43.06 / 4
Evaporative Heating Surface (sq ft / m2)1894 / 176
Superheating Surface (sq ft / m2)700 / 65
Combined Heating Surface (sq ft / m2)2594 / 241
Evaporative Heating Surface/Cylinder Volume168.01
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,119
Same as above plus superheater percentage12,851
Same as above but substitute firebox area for grate area49,793
Power L119,134
Power MT1222.62

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