Bulgarian State 4-10-0 Locomotives in Bulgaria

Class Details by Steve Llanso of Sweat House Media

Class 11 (Locobase 1589)

[] (viewed 18 July 2003). Tube diameters are inner dimensions.

Rare 4-10-0 of typical late-30s German design, 10 of which were built by Henschel in 1939 and 12 more delivered by Skoda and Borsig in 1943. The engine had a long, untapered boiler, long sand dome behind the steam dome, smoke-lifting elephant ears, and Walschaerts gear supplying pistons that drove on the second axle. Note the very high boiler demand factor and low factor of adhesion.

Trifonov notes that these were supplied to a requirement to pull heavy passenger trains at 75 km/h (46.6 mph); they could indeed sustain 60 km/h (37.3 mph). After a few years of passenger work, the Class 11s were sent to freight service.

Despite their long service, Class 11s were not popular with their crews. They were complicated and suffered from frailties in their inside valve gear. Yet, when in 1959 some Class 01 drivers were set to repairing the Class 11s as they warranted, reliability shot up.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID1589
RailroadBulgarian State
Number in Class22
Road Numbers11.01-22
Number Built22
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)22.97 / 7
Engine Wheelbase (ft / m)35.76 / 10.90
Ratio of driving wheelbase to overall engine wheelbase 0.64
Overall Wheelbase (engine & tender) (ft / m)64.32 / 19.60
Axle Loading (Maximum Weight per Axle) (lbs / kg)37,479 / 17,000
Weight on Drivers (lbs / kg)187,393 / 85,000
Engine Weight (lbs / kg)238,540 / 108,200
Tender Loaded Weight (lbs / kg)156,484 / 70,980
Total Engine and Tender Weight (lbs / kg)395,024 / 179,180
Tender Water Capacity (gals / ML)7398 / 28.02
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)14.30 / 13
Minimum weight of rail (calculated) (lb/yd / kg/m)62 / 31
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57.10 / 1450
Boiler Pressure (psi / kPa)232.10 / 16
High Pressure Cylinders (dia x stroke) (in / mm)20.47" x 27.56" / 520x700 (3)
Tractive Effort (lbs / kg)59,850 / 27147.54
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.13
Heating Ability
Tubes (number - dia) (in / mm)127 - 1.93" / 49
Flues (number - dia) (in / mm)38 - 5.31" / 135
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)158.39 / 14.72
Grate Area (sq ft / m2)52.40 / 4.87
Evaporative Heating Surface (sq ft / m2)2411 / 224.07
Superheating Surface (sq ft / m2)881 / 81.88
Combined Heating Surface (sq ft / m2)3292 / 305.95
Evaporative Heating Surface/Cylinder Volume153.11
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation12,162
Same as above plus superheater percentage15,446
Same as above but substitute firebox area for grate area46,688
Power L115,615
Power MT918.53

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