Bulgarian State 0-12-0 Locomotives in Bulgaria


Class Details by Steve Llanso of Sweat House Media

Class 4000/45 (Locobase 1599)

[link] (viewed 18 July 2003). See also Desider Ledacs Kiss, "0-12-0 Locomotives for Bulgarian State Rys", Railway Review, Volume 73, No 4 (28 July 1923), pp. 126-127. See also Douglas Self, "The Bulgarian State Class 45" in Self's Twelve-coupled Locomotives at [link], last accessed 13 February 2024. Tube diameters are inner dimension. Trifonov's illustrations showed that the rigid wheelbase measure 4.335 m (14.22 ft), a good thing given the six axles under the boiler.

Tufnell (1986) commented on the relatively antiquated mechanical design of these locomotives, noting that they were "among the last engines to adopt the two-cylinder compound cycle and to use saturated steam."

Six coupled axles on a rigid (ish) frame and rolling on a skinny gauge called for a complex assignment of duties, as outlined by Douglas Self:

" The arrangements for getting round curves were as follows:

The 1st axle had 28 mm of transverse movement.

The 2nd and 5th axles had no transverse movement, defining the fixed wheelbase.

The 3rd axle had 15 mm of transverse movement.

The 4th axle had flangeless wheels.

The 6th axle had 28 mm of transverse movement."

Desider Kiss reported that the reason for not using superheaters lay "in the difficulty in maintaining this device in Bulgaria, where locomotive repair shops are very inadequate." Indeed earlier experience found that "maintenance proved so expensive that, considering the first cost of the locomotive, it was more economical to buy saturated steam locomotives." Moreover, the local Pernik coal had such a low heating value, superheat temperatures would be impossible to achieve.

Eventually they were superheated and simpled, their equal-diameter, 620-mm cylinders being supplied through Lentz poppet valves; see Locobase 5660. The last of these was retired in 1955.

An illustration shows a heavy profile with three small domes, the steam dome centered in the boiler over the third driving axle and two sand domes (one between the first second axles, the other over the fifth). At one end was a large vestibule cab, at the other a grilled pilot and small tapered stack.


Class 45 - superheated (Locobase 5660)

[link] (viewed 18 July 2003). See also Douglas Self, "The Bulgarian State Class 45" in Self's Twelve-coupled Locomotives at [link], last accessed 13 February 2024.(Thanks to Alexander Blessing for his 4 February 2024 email pointing out the correct agent of the superheater upgrade and questioning the overall wheelbase.)

This is the superheated version of the original saturated steam locomotive shown in Locobase 1590. BDZ's shops adopted Lentz poppet valves, wrote Simeon Trifonov, because the compound imposed an unstable motion on the track. Although the demand factors climbed, the amount of raw power now available was considerable. Moreover, the locomotive's adhesion was equal to the demand.

Even so, the overhaul didn't extend the design's life remarkably, as the last engine retired in 1955.

Principal Dimensions by Steve Llanso of Middle Run Media
Class4000/4545 - superheated
Locobase ID1599 5660
RailroadBulgarian StateBulgarian State
CountryBulgariaBulgaria
Whyte0-12-0T0-12-0T
Number in Class1010
Road Numbers4001-4010/45.01-1045.01-10
GaugeStdStd
Number Built10
BuilderHanomagBDZ
Year19221948
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)23.70 / 7.2223.70 / 7.22
Engine Wheelbase (ft / m)23.70 / 7.2223.70 / 7.22
Ratio of driving wheelbase to overall engine wheelbase11
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)37,104 / 16,83037,104 / 16,900
Weight on Drivers (lbs / kg)222,667 / 101,000222,667 / 101,000
Engine Weight (lbs / kg)222,667 / 101,000222,667 / 101,000
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)222,667 / 101,000222,667 / 101,000
Tender Water Capacity (gals / ML)3168 / 123168 / 12
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 5.50 / 5 5.50 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)62 / 3162 / 31
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)52.80 / 134052.80 / 1340
Boiler Pressure (psi / kPa)217.60 / 1500217.60 / 1500
High Pressure Cylinders (dia x stroke) (in / mm)24.41" x 27.56" / 620x700 (1)24.41" x 27.56" / 620x700
Low Pressure Cylinders (dia x stroke) (in / mm)35.43" x 27.56" / 900x700 (1)
Tractive Effort (lbs / kg)39,009 / 17694.2157,525 / 26092.93
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.71 3.87
Heating Ability
Tubes (number - dia) (in / mm)332 - 2.047" / 52142 - 1.85" / 52
Flues (number - dia) (in / mm)34 - 4.92" / 133
Flue/Tube length (ft / m)15.98 / 4.87
Firebox Area (sq ft / m2)148.65 / 13.81148.60 / 13.81
Grate Area (sq ft / m2)49.51 / 4.6049.50 / 4.60
Evaporative Heating Surface (sq ft / m2)2674 / 248.411949 / 181.11
Superheating Surface (sq ft / m2)807 / 75
Combined Heating Surface (sq ft / m2)2674 / 248.412756 / 256.11
Evaporative Heating Surface/Cylinder Volume358.26130.56
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation10,77310,771
Same as above plus superheater percentage10,77313,895
Same as above but substitute firebox area for grate area32,34641,713
Power L1416212,770
Power MT247.25758.61

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