Bombay, Baroda & Central India - Rajputna Malwa 4-6-4 Locomotives in India

Class Details by Steve Llanso of Sweat House Media

Class superheated (Locobase 20464)

Data from "Tank Locomotives for the Bombay, Baroda & Central India Ry.,(Metre Gauge Section)", Locomotive Magazine, Volume XXII [22] (15 March 1916), pp. 42-43

After the first twelve double-ender tanks were built in the BB&C's Ajmer shops (Locobase 20463), the railway installed its own design of superheater (derived from the Schmidt firetube version) in the remaining four.

The quartet used the same Belpaire firebox and running gear, but increased cylinder diameter by an inch (25.4 mm) while dropping the boiler pressure setting by 35 psi (2.41 bar). Opinions varied on how to take advantage of the greater effectiveness in superheated steam and this choice sought to reduce maintenance demands while recouping some of the lost tractive effort through greater cylinder volume. Engine weight increased by a mere 438 lb (199 kg).

Class unknown (Locobase 20463)

Data from "Tank Locomotives for the Bombay, Baroda & Central India Ry.,(Metre Gauge Section)", Locomotive Magazine, Volume XIX [19], No 250 (14 June 1913), p. 120.

Continuing the line of locomotives such as the 4-6-0s in Locobase 20114 and the 4-4-0s in Locobases 20115-20116, these tanks were built in BB&CI's Ajmer shops under the direction of locomotive superintendent W S Fraser. Fitted with a Belpaire firebox, these were driven by outside cylinders supplied through slide valves actuated by Walschaert gear.

The railway proudly noted that "these engines are being entirely constructed in the Ajmer works, even the steel castings for the wheel centers, frame stretchers, etc., being of Indian manufacture." England supplied only the raw materials and "such fittings as ejectors, injectores, and lubricators."

After the first twelve, the shops installed their own design of superheater (derived from the Schmidt firetube in another four. See Locobase 20464.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID20464 20463
RailroadBombay, Baroda & Central India - Rajputna MalwaBombay, Baroda & Central India - Rajputna Malwa
Number in Class412
Road Numbers
Number Built412
BuilderBB&CI AjmerBB&CI Ajmer
Valve GearWalschaertWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)
Engine Wheelbase (ft / m)
Ratio of driving wheelbase to overall engine wheelbase
Overall Wheelbase (engine & tender) (ft / m)
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)
Engine Weight (lbs / kg)107,520 / 48,770107,072 / 48,567
Tender Loaded Weight (lbs / kg) / 24,385
Total Engine and Tender Weight (lbs / kg)
Tender Water Capacity (gals / ML)1680 / 6.361680 / 10.91
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) 3.30 / 3 3.30 / 4
Minimum weight of rail (calculated) (lb/yd / kg/m)
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)48 / 121948 / 1219
Boiler Pressure (psi / kPa)145 / 10180 / 12.40
High Pressure Cylinders (dia x stroke) (in / mm)16" x 22" / 406x55915" x 22" / 381x559
Tractive Effort (lbs / kg)14,461 / 6559.4115,778 / 7156.79
Factor of Adhesion (Weight on Drivers/Tractive Effort)
Heating Ability
Tubes (number - dia) (in / mm)155 - 1.75" / 44
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)10.32 / 3.1510.32 / 3.15
Firebox Area (sq ft / m2)83 / 7.7183 / 7.71
Grate Area (sq ft / m2)
Evaporative Heating Surface (sq ft / m2)699 / 64.94816 / 75.81
Superheating Surface (sq ft / m2)142 / 13.19
Combined Heating Surface (sq ft / m2)841 / 78.13816 / 75.81
Evaporative Heating Surface/Cylinder Volume136.53181.35
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation
Same as above plus superheater percentage
Same as above but substitute firebox area for grate area14,08114,940
Power L154203939
Power MT

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Wes Barris