Bonhomie Southwestern 2-6-2 "Prairie" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 4 (Locobase 14308)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Volume 52, p. 350. See also Mississippi Rails website's description at . Works number was 43121 in March 1916.

This logging road was chartered in August 1910 by Mississippi's Tatum Lumber Company. Anchored on the northern end at Hattiesburg, the line angled south to Okahola, then west to Columbia for a total of 35 miles (56.4 km). Mississippi Rails reports two conditions of note in the charter: Finish the road in five years and the road was "not required to operate freight and passenger trains on Sundays, except in emergencies, in the 'promotion of the Christian religion.'".

The Baldwin spec stated that the firebox of this wood-burning logging Prairie was to be placed on top of the frames (perhaps for clearance reasons?). Rail weights on the road were given as 56 lb/yard (28 kg/metre), maximum grades rose at 3%, and the line curved at a relatively gentle 14 degrees (radius of 410 feet/125 metres).

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID14,308
RailroadBonhomie Southwestern
Number in Class1
Road Numbers4
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)10.25 / 3.12
Engine Wheelbase (ft / m)26.83 / 8.18
Ratio of driving wheelbase to overall engine wheebase 0.38
Overall Wheelbase (engine & tender) (ft / m)50.58 / 15.42
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)92,000 / 41,731
Engine Weight (lbs / kg)121,000 / 54,885
Tender Loaded Weight (lbs / kg)80,000 / 36,287
Total Engine and Tender Weight (lbs / kg)201,000 / 91,172
Tender Water Capacity (gals / ML)4000 / 15.15
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)
Minimum weight of rail (calculated) (lb/yd / kg/m)51 / 25.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)44 / 1118
Boiler Pressure (psi / kPa)170 / 11.70
High Pressure Cylinders (dia x stroke) (in / mm)17" x 24" / 432x610
Tractive Effort (lbs / kg)22,778 / 10331.94
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.04
Heating Ability
Firebox Area (sq ft / m2)101 / 9.38
Grate Area (sq ft / m2)18.90 / 1.76
Evaporative Heating Surface (sq ft / m2)1637 / 152.08
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1637 / 152.08
Evaporative Heating Surface/Cylinder Volume259.64
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation3213
Same as above plus superheater percentage3213
Same as above but substitute firebox area for grate area17,170
Power L14235
Power MT304.45

All material Copyright ©
Wes Barris