Assam Bengal Beyer-Garratt Locomotives in India


Class Details by Steve Llanso of Sweat House Media

Class T (Locobase 685)

Data from Wiener (1930) and from "Assam Bengal Railway-Design 1127", Beyer-Garrrat Patent Articulated Locomotives (Manchester, England: Beyer-Peacock & Company Limited, 1931), archived on flickr's Historical Railway Images at [], et seq, p. 28. Works numbers were 6385-6389 in 1931.

Prairie Garratts bought to work mixed-traffic trains over The Hill over ruling gradients of 1 in 60 (1.67%) and an 11-mile (17.7-km) section between Harangaja and Jatinga up 1 in 37 (2.7%). Described by BP as "a conspicuous example of perseverance and engineering skill overcoming almost insuperable difficulties, the 115 1/4 (185.6 km) miles required 37 tunnels and "numerous bridges" and curves as tight as 382 ft.

Acknowledging that such obstacles required all trains, including those headed by a Garratt, to use "banking" engines, BP was nonetheless able to claim that the average Garratt trainload measured 300 tons or 30% more than "the most powerful EIGHT-coupled locomotives." Moreover, the Garratt's lower axle load and greater flexibility, they claimed, had "added materially to the safe working of this section."

Principal Dimensions by Steve Llanso of Sweat House Media

ClassT
Locobase ID685
RailroadAssam Bengal
CountryIndia
Whyte2-6-2+2-6-2
Number in Class5
Road Numbers401-405
GaugeMetre
Number Built5
BuilderBeyer, Peacock
Year1927
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)17.83 / 5.43
Engine Wheelbase (ft / m)38.67 / 11.79
Ratio of driving wheelbase to overall engine wheelbase 0.46
Overall Wheelbase (engine & tender) (ft / m)59 / 17.98
Axle Loading (Maximum Weight per Axle) (lbs / kg)21,280 / 9652
Weight on Drivers (lbs / kg)127,680 / 57,915
Engine Weight (lbs / kg)202,048 / 91,648
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)202,048 / 91,648
Tender Water Capacity (gals / ML)2400 / 9.09
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 6.70 / 6.10
Minimum weight of rail (calculated) (lb/yd / kg/m)35 / 17.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 1219
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)14" x 24" / 356x610 (4)
Tractive Effort (lbs / kg)29,988 / 13602.34
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.26
Heating Ability
Tubes (number - dia) (in / mm)186 - 1.75" / 44
Flues (number - dia) (in / mm)26 - 5.25" / 133
Flue/Tube length (ft / m)
Firebox Area (sq ft / m2)132 / 12.26
Grate Area (sq ft / m2)30 / 2.79
Evaporative Heating Surface (sq ft / m2)1430 / 132.85
Superheating Surface (sq ft / m2)268 / 24.90
Combined Heating Surface (sq ft / m2)1698 / 157.75
Evaporative Heating Surface/Cylinder Volume167.21
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5400
Same as above plus superheater percentage6264
Same as above but substitute firebox area for grate area27,562
Power L17580
Power MT785.29

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