Siberian Articulated Locomotives in Russia

Class Details by Steve Llanso of Sweat House Media

Class unknown (Locobase 20506)

Data from "Mallet Articulated Compounds for the Siberian Railroad", Railroad Gazette, Volume XXXVI [36], No 16 (15 April 1904), p. 285. See also a brief note in James Grant, "Mechanical Equipment on the Tomsk Railway", Railway Mechanical Engineer, Volume 95, No 1 (January 1921), pp. 7-14.

These wood-burners were rated to pull a 500 ton trailing load at 15-20 kph (10-12 mph) up a 1.67% grade. At the time of the RG report just before the beginning of the 1904-1905 Russo-Japanese War, they'd been in service since 1899 and were well-regarded. 80 of the class had either entered service or were in production. James Grant's report published 15 years later gave the final figure of 250 completed by Bransk (sic-Bryansk is the usual transliteration), Putilov, and Kolomensk (sic).

Grant's quite positive appraisal of the design stemmed in part from its reputation as "one of the most successful for freight service on the whole Trans-Siberian system." Slab frames made of 1 1/4" (32 mm) plate meant "breakage is unknown." Likewise, ball and sleeve joints of "special construction" were fitted to the receiver pipes so they too showed "little trouble from steam leakage."

See Locobase 20505 for a more on the Tomsk Railway.

(NB: The tube heating surface area in Locobase's specs is based on the outside diameter of 2". Areas in the RG table were derived from the tubes' inside (fire side) diameters and totalled 1,871 sq ft (173.82 sq m). Adding that to the firebox heating surface area resulted in an evaporative heating surface area of 2,026 sq ft (188.20 sq m).)

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID20506
RailroadSiberian (Tomsk)
Number in Class230
Road Numbers
Number Built230
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m) 8.53 / 2.60
Engine Wheelbase (ft / m)23.29 / 7.10
Ratio of driving wheelbase to overall engine wheelbase 0.37
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)180,999 / 82,100
Engine Weight (lbs / kg)180,999 / 82,100
Tender Loaded Weight (lbs / kg)111,995 / 50,800
Total Engine and Tender Weight (lbs / kg)292,994 / 132,900
Tender Water Capacity (gals / ML)
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)50 / 25
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)47.20 / 1200
Boiler Pressure (psi / kPa)175.50 / 12.10
High Pressure Cylinders (dia x stroke) (in / mm)18.7" x 25.59" / 475x650
Low Pressure Cylinders (dia x stroke) (in / mm)27.95" x 25.59" / 710x650
Tractive Effort (lbs / kg)39,073 / 17723.24
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.63
Heating Ability
Tubes (number - dia) (in / mm)265 - 2.008" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)14.76 / 4.50
Firebox Area (sq ft / m2)155 / 14.40
Grate Area (sq ft / m2)37.67 / 3.50
Evaporative Heating Surface (sq ft / m2)2211 / 205.40
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2211 / 205.40
Evaporative Heating Surface/Cylinder Volume271.81
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation6611
Same as above plus superheater percentage6611
Same as above but substitute firebox area for grate area27,203
Power L12269
Power MT165.82

All material Copyright ©
Wes Barris