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 | |
|---|---|
| Class | Ta |
| Locobase ID | 730 |
| Railroad | Soviet State |
| Country | Soviet Union |
| Whyte | 2-10-4 |
| Number in Class | 5 |
| Road Numbers | 10,000 |
| Gauge | 5' |
| Number Built | 5 |
| Builder | Alco |
| Year | 1931 |
| Valve Gear | Walschaert |
| 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 Volume | 198.56 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 20,477 |
| Same as above plus superheater percentage | 26,620 |
| Same as above but substitute firebox area for grate area | 134,612 |
| Power L1 | 25,324 |
| Power MT | 1115.20 |