Firebox fitted with combustion chamber, which contributed to the firebox heating surface area as did 14 sq ft of arch tubes and 73 sq ft of thermic syphons. These were the standard USRA Light Mountain design. According to Charles B Castner, writing in Drury (1993), these J1s were immediately successful on the Chattanooga Division. Baldwin delivered 8 more with revised boilers and fireboxes in 1922 and 1925; see Locobase 212.
Although bumped from the premium runs by the J2 and J3 4-8-4s, the class ran until 1949-1951.
After Alco's Richmond works supplied five USRA Light Mountain locomotives to the N, C & St L in 1919 (see Locobase 8329). When the 4-8-2 proved its worth, the road turned to Baldwin for more Mountains. Although the power dimensions were the same, the boiler saw a drop in small tubes in favor of more superheater flues. The firebox was fitted with combustion chamber, which contributed 107 sq ft (9.95 sq m) to the firebox heating surface area as did 27 sq ft (2.5 sq m) of arch tubes - the total was 348 sq ft.
Within a few years the supplementary heating area would be changed by removing two of the four arch tubes (leaving 14 sq ft (1.25 sq m) of arch tubes) and adding 76 sq ft of thermic syphons to arrive at a total of 411 sq ft of direct heating surface.
They served the NC & St L for more than 25 years before heading to the scrapyard in September 1949 (6) and October 1950 (556 and 558).
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Nashville, Chattanooga & St. Louis (NC&StL)||Nashville, Chattanooga & St. Louis (NC&StL)|
|Number in Class||5||8|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||18.25 / 5.56||18.25 / 5.56|
|Engine Wheelbase (ft / m)||40 / 12.19||40 / 12.19|
|Ratio of driving wheelbase to overall engine wheebase||0.46||0.46|
|Overall Wheelbase (engine & tender) (ft / m)||75.83 / 23.11||77.33 / 23.57|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)|
|Weight on Drivers (lbs / kg)||224,500 / 101,832||224,500 / 101,832|
|Engine Weight (lbs / kg)||327,000 / 148,325||340,000 / 154,222|
|Tender Loaded Weight (lbs / kg)||192,000 / 87,090||192,000 / 87,090|
|Total Engine and Tender Weight (lbs / kg)||519,000 / 235,415||532,000 / 241,312|
|Tender Water Capacity (gals / ML)||10,000 / 37.88||10,000 / 37.88|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||16 / 14.50||16 / 14.50|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||94 / 47||94 / 47|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||69 / 1753||69 / 1753|
|Boiler Pressure (psi / kPa)||200 / 13.80||200 / 13.80|
|High Pressure Cylinders (dia x stroke) (in / mm)||27" x 30" / 686x762||27" x 30" / 686x762|
|Tractive Effort (lbs / kg)||53,883 / 24440.95||53,883 / 24440.95|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.17||4.17|
|Firebox Area (sq ft / m2)||408 / 37.92||411 / 38.20|
|Grate Area (sq ft / m2)||70.30 / 6.53||70.30 / 6.53|
|Evaporative Heating Surface (sq ft / m2)||4181 / 388.57||4039 / 375.37|
|Superheating Surface (sq ft / m2)||966 / 89.78||1080 / 100.37|
|Combined Heating Surface (sq ft / m2)||5147 / 478.35||5119 / 475.74|
|Evaporative Heating Surface/Cylinder Volume||210.31||203.17|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||14,060||14,060|
|Same as above plus superheater percentage||16,731||17,013|
|Same as above but substitute firebox area for grate area||97,104||99,462|