Soviet State 2-10-4 Locomotives in Russia


Class Details by Steve Llanso of Sweat House Media

Class Ta (Locobase 730)

Data from Alco specs card Class 2-10-4 S 166 supplied by Alexander Blessing in his 4 January 2024 email; and "Diagrams [of] Locomotives and 'Passports' [sic]", published in Moskva (Moscow), 1935 p. 84-85, PDF supplied by Teemu Koivmaki in his 5 October 2019 email. (Many thanks to Teemu for sending what might never have fallen into Locobase's hands. An indispensable addition to Locobase's library.). See also Alfred W Bruce, The Steam Locomotive in America - Its development in the twentieth century (New York: W W Norton, 1952), p. 368. (Thanks to Alexander Blessing for his 4 January 2025 email supplying the Alco builder's card noted above. Locobase was able to compare data with the 1935 Soviet diagram book and adjust as necessary.

Five of this arrangement (and five 2-10-2s by Baldwin-see Locobase 728) were built for the Soviet Union. Compared to the Baldwins, these Alcos pressed harder and had a bigger evaporative surface area. Both had impressive superheat ratios. Frebox heating surface area included a combustion chamber, 1.65 sq m (17.75 sq ft) in arch tubes and 7.35 sq m (79.11 sq ft) in syphons, A thwartship-place cylinder over the smokebox implies an Elesco feed water heater. For such a large boiler, the two 305 mm (12") piston valves seem small.

See the Baldwin entry at Locobase 728 for a discussion of Soviet intent.

Principal Dimensions by Steve Llanso of Middle Run Media
ClassTa
Locobase ID730
RailroadSoviet State
CountrySoviet Union
Whyte2-10-4
Number in Class5
Road Numbers10,000
Gauge5'
Number Built5
BuilderAlco
Year1931
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)21 / 6.40
Engine Wheelbase (ft / m)42.19 / 12.86
Ratio of driving wheelbase to overall engine wheelbase 0.50
Overall Wheelbase (engine & tender) (ft / m)85.07 / 25.93
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)250,313 / 113,540
Engine Weight (lbs / kg)365,261 / 165,680
Tender Loaded Weight (lbs / kg)275,578 / 125,000
Total Engine and Tender Weight (lbs / kg)640,839 / 290,680
Tender Water Capacity (gals / ML)11,616 / 44
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)24.20 / 22
Minimum weight of rail (calculated) (lb/yd / kg/m)83 / 41.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)59.80 / 1520
Boiler Pressure (psi / kPa)239.30 / 1650
High Pressure Cylinders (dia x stroke) (in / mm)27.56" x 29.92" / 700x760
Tractive Effort (lbs / kg)77,300 / 35062.73
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.24
Heating Ability
Tubes (number - dia) (in / mm)55 - 2.244" / 57
Flues (number - dia) (in / mm)175 - 3.504" / 89
Flue/Tube length (ft / m)19.03 / 5.80
Firebox Area (sq ft / m2)432.71 / 40.20
Grate Area (sq ft / m2)85.57 / 7.95
Evaporative Heating Surface (sq ft / m2)4102 / 381.13
Superheating Surface (sq ft / m2)1741 / 161.71
Combined Heating Surface (sq ft / m2)5843 / 542.84
Evaporative Heating Surface/Cylinder Volume198.56
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation20,477
Same as above plus superheater percentage26,620
Same as above but substitute firebox area for grate area134,612
Power L125,324
Power MT1115.20

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