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 Middle Run Media | |
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Class | T |
Locobase ID | 685 |
Railroad | Assam Bengal |
Country | India |
Whyte | 2-6-2+2-6-2 |
Number in Class | 5 |
Road Numbers | 401-405 |
Gauge | Metre |
Number Built | 5 |
Builder | Beyer, Peacock |
Year | 1927 |
Valve Gear | Walschaert |
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) | |
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 / 1240 |
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 Volume | 167.21 |
Computations Relating to Power Output (More Information) | |
Robert LeMassena's Power Computation | 5400 |
Same as above plus superheater percentage | 6264 |
Same as above but substitute firebox area for grate area | 27,562 |
Power L1 | 7580 |
Power MT | 785.29 |