New Orleans Pacific / Texas & Pacific 4-4-0 "American" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class A-2 (Locobase 8495)

Data from T&P 1 - 1922 & T&P 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection. Works numbers were 1343-1344 in January 1882, 1357-1361 in February.

The first two locomotives were ordered by Pacific Improvement Co; the books show

the latter five had International Improvement Co. as the buyer. At some point, the T&P converted the coal-burners to oil-burning.

The entire class remained in service for more than 30 years. 119 was scrapped in January 1916, 118 followed in August, 120-121 in September. 122 made 37 years before it arrived at the ferro-knackers in July 1919. 117 reached 43 years before its dismantling in July 1925.

Class A-4 (Locobase 8496)

Data from T&P 1 - 1922 & T&P 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Raildata collection.

One notable feature of this design was the widely spread drivers, which allowed a long, narrow firebox to be fit between the frames and the axles. The last of the class was dismantled in January 1926.

Specifications by Steve Llanso of Sweat House Media
Locobase ID8495 8496
RailroadNew Orleans Pacific (T&P)Texas & Pacific (T&P)
Number in Class63
Road Numbers117-123/542-547/117-123186-188
Number Built63
BuilderDanforth, CookeNew York
Valve GearStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft)8 9.37
Engine Wheelbase (ft)21.8323.73
Ratio of driving wheelbase to overall engine wheebase 0.37 0.39
Overall Wheelbase (engine & tender) (ft)46.1248.58
Axle Loading (Maximum Weight per Axle) (lbs)
Weight on Drivers (lbs)47,00060,500
Engine Weight (lbs)75,00095,000
Tender Loaded Weight (lbs)65,00070,000
Total Engine and Tender Weight (lbs)140,000165,000
Tender Water Capacity (gals)40004500
Tender Fuel Capacity (oil/coal) (gals/tons)15001800
Minimum weight of rail (calculated) (lb/yd)3950
Geometry Relating to Tractive Effort
Driver Diameter (in)6363
Boiler Pressure (psi)145150
High Pressure Cylinders (dia x stroke) (in)16" x 24"18" x 24"
Tractive Effort (lbs)12,02015,737
Factor of Adhesion (Weight on Drivers/Tractive Effort) 3.91 3.84
Heating Ability
Firebox Area (sq ft)100155
Grate Area (sq ft)1618
Evaporative Heating Surface (sq ft)10051305
Superheating Surface (sq ft)
Combined Heating Surface (sq ft)10051305
Evaporative Heating Surface/Cylinder Volume179.94184.62
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation23202700
Same as above plus superheater percentage23202700
Same as above but substitute firebox area for grate area14,50023,250
Power L141034635
Power MT384.92337.80


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