New Orleans Great Northern 4-8-2 "Mountain" Locomotives in the USA

The area around New Orleans is typically soft and spongy. When the New Orleans Great Northern needed a locomotive that was larger and faster than their 2-8-2s, it chose a light Mountain type. Normally, the purpose of the four-wheel leading truck of a locomotive is to assist in smooth running at speed. However, in the case of the New Orleans Great Northern, the purpose was to simply spread out the weight of the locomotive. At 273,000 lbs, the New Orleans Great Northern Mountains were one of the lightest of the type.

In 1929 the Gulf, Mobile & Ohio acquired the New Orleans Great Northern.


CNRoad NumbersYear BuiltBuilder

Class Details by Steve Llanso of Sweat House Media

Class 200 / 500 (Locobase 6909)

Data from GM&O 5 -1945 Locomotive Diagram books supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 67316-67318 in June 1927.

This Mountain trio bore the second lightest weight of any 4-8-2s supplied to a North American railroad, according to Drury. They had 14" (356 mm) piston valves. Firebox heating surface area included 24 sq ft (2.23 sq m) of arch tubes.

The NO&NE merged with the Gulf, Mobile & Northern in 1933 and these engines were renumbered in the 500 series. After World War Two, the GM&N sold the 500 to locomotive rebuilder/reseller Birmingham Rail & Locomotive. Together with Georgia Car & Locomotive, the BR&L found a new owner in the Georgia & Florida in May 1947; the G&F renumbered it 600. In October 1947, the other two engines in the class joined the 600 in October of that year.

After three years of service, all three were scrapped in October 1950.

Principal Dimensions by Steve Llanso of Sweat House Media

Class200 / 500
Locobase ID6909
RailroadNew Orleans Great Northern (GM&O)
Number in Class3
Road Numbers200-202, 500-502
Number Built3
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)16.75 / 5.11
Engine Wheelbase (ft / m)37 / 11.28
Ratio of driving wheelbase to overall engine wheelbase 0.45
Overall Wheelbase (engine & tender) (ft / m)69.94 / 21.32
Axle Loading (Maximum Weight per Axle) (lbs / kg)47,750 / 21,659
Weight on Drivers (lbs / kg)191,000 / 86,636
Engine Weight (lbs / kg)272,500 / 123,604
Tender Loaded Weight (lbs / kg)175,400 / 79,560
Total Engine and Tender Weight (lbs / kg)447,900 / 203,164
Tender Water Capacity (gals / ML)9000 / 34.09
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)16 / 15
Minimum weight of rail (calculated) (lb/yd / kg/m)80 / 40
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)63 / 1600
Boiler Pressure (psi / kPa)225 / 15.50
High Pressure Cylinders (dia x stroke) (in / mm)24" x 28" / 610x711
Tractive Effort (lbs / kg)48,960 / 22207.91
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.90
Heating Ability
Tubes (number - dia) (in / mm)167 - 2" / 51
Flues (number - dia) (in / mm)30 - 5.375" / 137
Flue/Tube length (ft / m)19.83
Firebox Area (sq ft / m2)258 / 23.98
Grate Area (sq ft / m2)59.90 / 5.57
Evaporative Heating Surface (sq ft / m2)2832 / 263.20
Superheating Surface (sq ft / m2)600 / 55.76
Combined Heating Surface (sq ft / m2)3432 / 318.96
Evaporative Heating Surface/Cylinder Volume193.18
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation13,478
Same as above plus superheater percentage15,769
Same as above but substitute firebox area for grate area67,919
Power L115,345
Power MT708.48

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Wes Barris