Great Indian Peninsula 2-8-4 Locomotives in India

Class Details by Steve Llanso of Sweat House Media

Class Y (Locobase 6746)

Data from [] (visited 11 Aug 2005). See also "New Locomotives for the Great Indian Peninsula Ry," The Locomotive Magazine, Vol XII (15 May 1906), p. 73

The diagram shows the classic Belpaire firebox on this big engine, which was produced to tackle the increased train loads scaling the famous Bhore Ghat inclines. The Ghat range separates Central India from Bombay (later renamed Mumbai) and at the time of the construction of the GIPR, the only possible way to scale them was to saw back and forth up the incline through the use of reversing stations (or switchbacks).

A tank engine lent itself to this duty because it was easier to operate in both directions and this class was seen as the largest possible exemplars of such haulers. They were rated at 350 tons moving at 10 mph up the 1 in 37 (2.7%) grade and the LM report predicted that "...this ability to deal with a heavy load unaided will obviate the necessity for a considerable amount of 'double heading' now resorted to to cope with the traffic."

Principal Dimensions by Steve Llanso of Middle Run Media

Locobase ID6746
RailroadGreat Indian Peninsula (GIPR)
Number in Class
Road Numbers322
Number Built
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.50 / 4.72
Engine Wheelbase (ft / m)35 / 10.67
Ratio of driving wheelbase to overall engine wheelbase 0.44
Overall Wheelbase (engine & tender) (ft / m)35 / 10.67
Axle Loading (Maximum Weight per Axle) (lbs / kg)36,064 / 16,358
Weight on Drivers (lbs / kg)144,032 / 65,332
Engine Weight (lbs / kg)212,912 / 96,575
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)212,912 / 96,575
Tender Water Capacity (gals / ML)
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)60 / 30
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)51 / 1295
Boiler Pressure (psi / kPa)180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)20" x 26" / 508x660
Tractive Effort (lbs / kg)31,200 / 14152.10
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.62
Heating Ability
Tubes (number - dia) (in / mm)
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)12.50 / 3.81
Firebox Area (sq ft / m2)173 / 16.08
Grate Area (sq ft / m2)32 / 2.97
Evaporative Heating Surface (sq ft / m2)2079 / 193.22
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)2079 / 193.22
Evaporative Heating Surface/Cylinder Volume219.91
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5760
Same as above plus superheater percentage5760
Same as above but substitute firebox area for grate area31,140
Power L14765
Power MT291.74

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Wes Barris