Works numbers were:
February 41904-41908; March 41928-41932; October 42607-42611
April 48223-48224; May 48574-48575, 48735,48779; June 48903, 48953, 49084; July 49234
These Mikes were the "Jitneys" to their crews (Charles B Castner in Drury (1993) doesn't say why). Among the lightest Mikes of their time, these well-balance engines served the main freight drags for years. Their relatively small dimensions included a cylinder volume that was served by 15" (381 mm) piston valves. As delivered, these Mikes had 26.6 sq ft (2.5 sq m) of arch tubes. A later retrofit deleted two of the four tubes and installed 73 sq ft (6.8 sq m) of thermic syphons to arrive at the firebox heating surface area shown in the specifications.
Prince observes: "...the L1 Mikado proved to be the most flexible freight engine on the road, operating as needed into Atlanta, Memphis, Martin, and Paducah." Prince added that in later years, the class would work as helpers and west of Nashville.
Their retirements occurred over an 8-year period from 1942-1950.
This was the basic USRA light Mikado (Locobase 40) with its generous grate and 14" piston valves as later modified by the NC & StL to boost its firebox heating surface. Deleting two of the arch tubes made room for 73 sq ft of thermic syphons. For some reason, the 650s wheelbase was slightly extended, especially in the firebox. One of the class -- 656 -- is shown in Locobase 8331 because of its very high superheat ratio.
This appears to be a one-off experiment in which the railroad took one of its Light USRA Mikados and introduced Type E superheating. This required considerable modification of the boiler and the installation of a front-end multiple throttle, reduction of the arch tube area to 14 sq ft in favor of 73 sq ft of thermic syphon. 656 retained most of the rest of the system (same grate, same 14" piston valves).
Although the result presumably generated a good more power., the NC & StL did not modify any others.
After taking ten USRA Light Mikados in 1918, the N, C & St L adopted the power dimensions but had Baldwin redo the boiler to add more superheater area. They had considerable supplementary direct heating surface area in the combustion chamber (52 sq ft /4.8 sq m), thermic syphons (81 sq ft/7.5 sq m), and fire brick tubes (14 sq ft/1.3 sq m). Fourteen-inch (356 mm) piston valves supplied the cylinders. Also fitted with Vanderbilt tenders, Precision power reverse gear, and cast trailing trucks with boosters.
Together with the USRA engines, these L2s "...handled mainline freights systemwide through World War II ..." according to Charles B Castner, writing in Drury (1993). They finished their days as pushers in the Cumberland Mountains.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Nashville, Chattanooga & St. Louis (NC&StL)||Nashville, Chattanooga & St. Louis (NC&StL)||Nashville, Chattanooga & St. Louis (NC&StL)||Nashville, Chattanooga & St. Louis (NC&StL)|
|Number in Class||29||10||1||12|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||15.75 / 4.80||16.75 / 5.11||15.75 / 4.80||16.75 / 5.11|
|Engine Wheelbase (ft / m)||34.33 / 10.46||36.92 / 11.25||36.08 / 11||36.92 / 11.25|
|Ratio of driving wheelbase to overall engine wheebase||0.46||0.45||0.44||0.45|
|Overall Wheelbase (engine & tender) (ft / m)||69.62 / 21.22||71.37 / 21.75||71.37 / 21.75||73.21 / 22.31|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)|
|Weight on Drivers (lbs / kg)||213,000 / 96,615||226,000 / 102,512||220,000 / 99,790||226,600 / 102,784|
|Engine Weight (lbs / kg)||272,000 / 123,377||303,000 / 137,439||290,000 / 131,542||306,200 / 138,890|
|Tender Loaded Weight (lbs / kg)||148,000 / 67,132||191,340 / 86,790||191,340 / 86,790||175,000 / 79,379|
|Total Engine and Tender Weight (lbs / kg)||420,000 / 190,509||494,340 / 224,229||481,340 / 218,332||481,200 / 218,269|
|Tender Water Capacity (gals / ML)||8000 / 30.30||10,000 / 37.88||10,000 / 37.88||10,000 / 37.88|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||13.50 / 12.30||16 / 14.50||16 / 14.50||16 / 14.50|
|Minimum weight of rail (calculated) (lb/yd)||89||94||92||94|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||58 / 1473||63 / 1600||63 / 1600||63 / 1600|
|Boiler Pressure (psi / kPa)||180 / 12.40||200 / 13.80||200 / 13.80||200 / 13.80|
|High Pressure Cylinders (dia x stroke) (in / mm)||25" x 30" / 635x762||26" x 30" / 660x762||26" x 30" / 660x762||26" x 30" / 660x762|
|Tractive Effort (lbs / kg)||49,461 / 22435.16||54,724 / 24822.42||54,724 / 24822.42||54,724 / 24822.42|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.31||4.13||4.02||4.14|
|Firebox Area (sq ft / m2)||328 / 30.48||377 / 35.04||377 / 35.04||351 / 32.61|
|Grate Area (sq ft / m2)||66.70 / 6.20||66.70 / 6.20||66.70 / 6.20||66.70 / 6.20|
|Evaporative Heating Surface (sq ft / m2)||3881 / 360.69||3874 / 360.04||3843 / 357.16||3694 / 343.18|
|Superheating Surface (sq ft / m2)||842 / 78.25||882 / 81.97||1600 / 148.70||1060 / 98.48|
|Combined Heating Surface (sq ft / m2)||4723 / 438.94||4756 / 442.01||5443 / 505.86||4754 / 441.66|
|Evaporative Heating Surface/Cylinder Volume||227.70||210.14||208.46||200.38|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||12,006||13,340||13,340||13,340|
|Same as above plus superheater percentage||14,167||15,875||17,209||16,275|
|Same as above but substitute firebox area for grate area||69,667||89,726||97,266||85,644|