Serbian State 2-6-6-2 Locomotives in Serbia

Class Details by Steve Llanso of Sweat House Media

Class 551/93 (Locobase 3604)

Data from Wiener (1930) and "Interesting Variety of Types of Locomotives for the Greek, Serbian, Belgian and Russian Governments built by the American Locomotive Company", Railway & Locomotive Engineering, Volume XXVIII [28], No. 12 (December 1915), pp. 406-409. Works numbers were 55117-55126 in April 1915.

Interesting Prairie Mallet that packed a lot of power on a very narrow gauge. R&LE's report focused on the very short turnaround after Serbian representatives placed the order on 8 February 1915: "All drawing room work was done in nineteen working days. The first engine had been designed, built, tested, knocked down and shipped on April 8."

R&LE also noted that the Mallets used outside frames "which was necessitated by a gauge of track of 30 inches."

Wiener noted that the firebox had arch tubes over a grate was that 29 1/8" shorter. His photograph shows a big-barrelled, tiny-drivered workhorse with external steam pipes leading from the dome to the HP cylinders. The HP cylinders received their steam through 7" (178 mm) piston valves, the larger LP cylinders used slide valves.

555 suffered a boiler explosion at some point in its early career. Four--551, 556, 558, 560-- took Austrian State numbers 6101-6104.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID3604
RailroadSerbian State (JDZ)
Number in Class10
Road Numbers551-560/93.001-93.009
Gauge76 cm
Number Built10
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m) 7.55 / 2.30
Engine Wheelbase (ft / m)34.45 / 10.50
Ratio of driving wheelbase to overall engine wheelbase 0.22
Overall Wheelbase (engine & tender) (ft / m)54.40 / 16.58
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)103,000 / 46,720
Engine Weight (lbs / kg)125,994 / 57,150
Tender Loaded Weight (lbs / kg)30,501 / 13,835
Total Engine and Tender Weight (lbs / kg)156,495 / 70,985
Tender Water Capacity (gals / ML)2500 / 9.47
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)5 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)29 / 14.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)35.80 / 910
Boiler Pressure (psi / kPa)200.20 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)12.99" x 20.08" / 330x510
Low Pressure Cylinders (dia x stroke) (in / mm)20.47" x 20.08" / 520x510
Tractive Effort (lbs / kg)22,964 / 10416.31
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.49
Heating Ability
Tubes (number - dia) (in / mm)157 - 2.008" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)15.09 / 4.60
Firebox Area (sq ft / m2)95.05 / 8.83
Grate Area (sq ft / m2)23.14 / 2.15
Evaporative Heating Surface (sq ft / m2)1332 / 123.75
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1332 / 123.75
Evaporative Heating Surface/Cylinder Volume432.46
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation4633
Same as above plus superheater percentage4633
Same as above but substitute firebox area for grate area19,029
Power L12823
Power MT362.54

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